$350-500 used is the sweet spot for the PST. I use mine for outreach at street festivals and observatory events. For that purpose it’s all you need. The average person isn’t going to care if it’s double stacked or at a larger aperture. They’ll see the sun in H-alpha and that’ll be a memory they keep. If you plan to image and be outside every day. Go nuts. Also remember if you live in the snow belt, we go weeks at a time barely even seeing the sun. So the value proposition changes if you live in the sun belt too 😆
Thank you Ed for taking the time to keep us well informed and entertained. Reliable information is getting hard to come by... You have taught me so much! Clear skies 😊
I bought my PST about one year after they first came out. Since then, it has been my most-used telescope by far as it sits ready to grab-and go all the time. The scope was de-rusted twice by Coronado/Meade and the changes implemented on it, as in the newer models, make it a lot better than it was. I have the third party solution for the rusted lens and it was cheap and easy to install. I have owned 60mm and 90mm Ha telescopes in the past and the one that is still with me is the venerable PST.
I've had my PST for 11 years and as a fairly casual sun observer, I don't see myself needing a more expensive solar scope anytime soon. I love the thing.
Bingo. I think too many people are in a rush to spend a fortune on a specialty product used on solely one object. Once you say it out loud “I’m only going to look at the sun with this!” and realize competitors are asking 3-4x what the PST costs, you come to your senses 😉
I had a PST for a while,. even met someone who had set up two PSTs side by side as a binocular solar telescope. I also had the original Coronado 40mm etalon and BF10 diagonal and used it on a Televue 76, a Televue 60 and a Tak 60FS. I called it my Ultraportable Solar Observatory and brought it to the NEAF Solar Star Party for years. When I retired, I wanted something more but the prices had skyrocketed. I have a Televue 85 that I got the Lunt 60 etalon and BF1200 diagonal for and I have been enjoying the much improved views. I don't care for double-stacking, I've tried that with a 60mm Lunt scope years back and I prefer the single-stack image. It is on an alt-az mount with slow motion controls so I can just carry it outside quick, use the Televue Sol Searcher to find the sun in an instant and enjoy a lengthy observing session. But the PST is not a bad way to break in. At today's prices, the advice to go used is a good one, save some now and then spend the rest on a better system if your interest grows.
I’ve had one of these for years. I bought it about a month before Meade bought Coronado. I love it and it piggy backs on whichever telescope I have the white light filter on. Makes a great combo.
I have a pst single and while it doesn't get much use, it's certainly more interesting with the solar maximum we're in... For the upcoming eclipses I have some white light film filters for my 6" and my c130, but I found that I needed an additional yellow - orange filter and adjustable polarizing filterto get the color and brightness closer to what my eyes/brain expect. I do like the better resolution provided by the bigger aperture for visual! I didn't have an eyepiece cam until this year so now I can give that a try on both rigs. On a smaller scope I'll be using a herschel wedge with a CaK filter on another refractor to try imaging with too. Getting pretty excited about that! 😁 To much to try and enough time... (as usual)
I just had my focuser repaired. Mine is quite old. Cost was about $200 and was worth it because they went over it and replaced a filter as well. Took about two months including transit time to Canada.
I love every review of yours. I wish i could watch a few everday but i understand it takes alot of effort to bring such a quality review for us to watch. Thanks for the trouble you go through. Regards
The only way I have observed the sun is eyepiece projection. A cheap 10mm eyepiece, bounced off a first surface mirror and a homemade screen, always completely safe.
I bought a second-hand SolarMax 40, which it turned out the owner was selling because the internal filters were degrading (although not noticeably to me at the time). I later bought a second-hand PST which I still have, and use double-stacked with the etalon from the other telescope. That was still OK and conveniently screws into the front of the PST, although the image is pretty dim with the double stack. Imaging with these scopes is difficult, and in my experience requires you take multiple images (or videos) and mosaic them together to get a full-disc image. The illumination is far from uniform across the field due to the small exit aperture, so flat-fielding each image is essential before joining them into a mosaic. If done carefully the result can be very pleasing, but it's a lot of effort and requires a level of skill that not all amateurs possess. I sometimes use the PST without the extra etalon just to look at the Sun in H-alpha, which is easy and the views are good. I would regard the PST as a very useful entry to solar viewing in H-alpha. If you decide it's not for you, or if it is but you want to upgrade, you'll probably be able to find a buyer for the PST without too much trouble.
I use solar film on my 100mm f5 Helios achromatic refractor. Using a green filter highlights the sunspots and allows imaging with a camera. Hydrogen alpha filters or calcium filters can easily be attached. An IR cut filter is essential for imaging.
A friend of mine had the PST and he liked it, but said forget about using much higher than 50x magnification for close ups because contrast starts to get a little hard to maintain. The double aperture rule doesn't apply with these and it being an achromat explains it. I got the 50mm Lunt for under a $1000 and am happy with it.
Thanks for another great review. I have a Lunt 40mm solar scope and have obtained surprisingly good whole disc images using a Player One Apollo Mini camera.
Great video, Ed! I went back and forth the PST and the Lunt 40 and ended up settling for the Lunt 40 and I'm happy with it. They also just released a double stack filter for it. it comes with a Tele Vue Sol Searcher which is super handy.
I'm interested in doing solar photography and have yet to figure out which one to get. This was a great video to give me an idea as to where I need to start.
Some PSTs, like mine, have a very bright image--bright enough that even during the middle of the day, my eye takes a minute or two to adjust to the brightness. I do recall observing through other PSTs, and yes, they had much dimmer images (and they were not double-stacked). The image in my PST is also more contrasty and detailed than I remember in other PSTs. Perhaps they suffered from the "rust" issue (either the objective lens in older PSTs or internal ITF in newer ones), which among other things, does dim the image. The 40mm aperture in the case of my particular PST (and that of some others I've heard about) is more than adequate in terms of light gathering. And because I'm getting such great views, I can't imagine that too much light is getting through--it's more like all the light that should be getting through actually is getting through.
It's true the aperture is too small but not only that but the focal length is very short resulting in a small image of the sun. And I had to use a higher power eyepiece but doing so dim the sun image and made it less contrasty. Also I didn't hear you mention the problem with the filters having a rust issue, and many had to be fixed, I would be wary of that on the used market getting a rust personal solar telescope. Maybe I didn't do something right but I sold my PST and wouldn't buy another one, they're just too small for a bright usable image, IMO.
From everything I have gathered online (and the bias of personally owning a Lunt), the Lunt 40 is a step above the PST, with a better bandpass (0.7 vs 1.0 Angstrom, lower meaning more contrast in the h-alpha features) and able to focus cameras without additional modifications. At a cheaper price too, so I'd recommend people research both.
I got the Lunt 50mm. It’s a work of art. Way better than the pst. Came with a hard case, pressure tuner and I upgraded to a Feathertouch focuser. Take away the focuser upgrade and it’s still about the same price. I feel like Lunt keeps their entry prices low because they know you’ll upgrade eventually and go with another Lunt. Customer service is unmatched as well.
For a long time the Lunt 40 wasn't even available new. It had been discontinued a long time ago and was brought back fairly recently. I bought my PST (barely) used for cheap during that time and I haven't regretted it, but I'm glad the Lunt 40 is back on the market.
I’d never suggest a double stacked PST, at that cost… it’s too much. Still, a used single stack PST for $350-500 is a stellar (all puns intended) deal!
Timely, thank you Ed! I have been considering getting into solar observing and feel like anything short of h-alpha would leave me wanting more. I have stayed away from filters and used equipment since there is basically no scope for error (safety wise) and I just can't trust pre-owned equipment for this. Will look into the PST!
I agree that anything less would leave you wanting more. That said, white light solar filters offer a different and, to my eye, clearer view of sunspots, as well as granulation, which you can't see distinctly in an H-alpha telescope. Granulation is easier to see with a medium/deep green filter (on the eyepiece), by the way, in addition to the solar film on the aperture.
@@rbrtck Thank you for your perspective! Am I correct in understanding that in buying a dedicated h-alpha scope such as this one (or the Lunt 40/50), there will be no way to see the sun in white light? If so, perhaps I can augment that purchase with filters for my existing scopes to achieve what you said. In refractors, I currently have a StellarVue SV80ST and ES ED127. Do you have filter recommendations for these? I am generally concerned about safety so the highest quality/reliability would be ideal.
@@mxms533 Correct, as dedicated H-alpha solar scopes, the Coronado PST and Lunt LS40THa/LS50THa can only be used to observe in H-alpha. Between them, I only have experience with the PST, and luckily for me, the PST I happen to own is truly exceptional--by far the best I've observed with. It's kind of ridiculous, actually, because it has no discernible "sweet spot", and I don't have to keep tuning it to see everything--I see everything at once over the entire image of the Sun very clearly. I haven't adjusted the tuning in years. The other PSTs I've used were decent, but they weren't like the one I have, and PSTs seem to have a lot of issues in general. If I had to guess, based on design, specs, and anecdotes from others, I'd say that you'll probably have better luck with one of the Lunt solar scopes. By the way, the basic Celestron or Meade 8-24mm zoom eyepiece goes great with the PST, and I can't imagine why it wouldn't be the same for the Lunt scopes, as well. I don't use that eyepiece for observing the night sky (I have better eyepieces for that), but it just works so well for H-alpha (as well or better than many of my otherwise superior eyepieces), in my experience, and gives you many magnifications in one package, of course. As for white light, to be honest, many people seem to abandon or mostly abandon observing the Sun in white light once they've made the move to H-alpha. I still observe in white light occasionally, when there are some nice, big sunspots I want to get a good, detailed look at, but the vast majority of my solar observing is done in H-alpha with my PST. You can see sunspots in H-alpha, but their details get swamped by everything else that is going on in the image, and the 40mm aperture is another limiting factor. So what I said about the advantages of white light observing is true, but I just wanted to offer a bit more perspective. If you're still interested in this, then your refractors are of course more than good enough for this purpose. As a personal preference, I would recommend a Baader AstroSolar visual white light solar filter. This is based on image quality, primarily. I made my own filter cell with the film that fits very tightly for safety, but Baader offer their own cells with the film installed (the film doesn't even have to be flat, and the image quality is superb regardless, in my opinion). I can't vouch for their cells myself, but they are a reputable manufacturer and their filter cells generally receive excellent reviews.
@@mxms533 Here is some additional information for completeness. An economical way to observe the Sun in H-alpha using larger, regular telescopes is to buy the DayStar Quark. While it has some limitations in comparison to dedicated H-alpha scopes, at about $1300, it's a lot cheaper than buying a larger H-alpha scope, and with larger apertures than the 40-50mm of the entry-level H-alpha scopes, you get better resolution, of course. It's an interesting and popular alternative, and you get to use your current very nice refractors and all that comes with this. I highly recommend using a front-mounted energy-rejection filter with this setup, by the way, to protect your telescope and the Quark from excessive heat. If you're interested, I can go into more depth, and of course you might want to look this up for yourself, as well. Regarding white light observing, I recommended the Baader AstroSolar visual film filter because it is both rather economical and of very high quality in terms of image. It also actually presents the Sun in white light, as in it looks white and is full-spectrum. Other polymer film-based filters color the Sun quite a bit (typically orange), and do not offer nearly the same image quality, in my opinion. But there are some alternatives. There are glass filters (like the one that Ed showed) that likewise present the Sun as white (maybe some don't, so check) and provide a high quality image. But they are heavier, quite a bit more expensive, and in my opinion aren't quite as good optically as the AstroSolar film. Another alternative (the last one for direct viewing, I think) is to use a Herschel wedge/prism. This old technology actually provides the highest white light image quality and most faithful representation of the Sun's spectrum, albeit it has some drawbacks, as well. One drawback is cost, as it is the most expensive solution, and not everyone is willing to spend so much on observing the Sun in white light, unless they are a sunspot connoisseur/fanatic (not that there is anything wrong with that, of course) or want to take the highest quality photos in white light. Another drawback is that most of the Sun's energy is blasted out of the device (watch out!), which tends to keep getting warmer anyway; some even absorb the heat with a heavy heat sink instead. For those who want only the best white light image quality, the Herschel wedge is where it's at, no question about it, but for most people the Baader AstroSolar film is the best fit, as it works nearly as well for a small fraction of the price and has none of the drawbacks (and it spares your telescope from the heat of the Sun by reflecting nearly all of its energy away before it enters). Finally, there is the even older method of solar projection (used by Galileo and his contemporaries, with Thomas Harriot probably being the first among them all). That's still great for observing solar eclipses today, and you can see sunspots, although I think you are going for direct views instead for greater detail. I just thought I'd mention it, both for completeness and because of your emphasis on safety. There is no safer way to observe the Sun in white light, besides using a camera instead of your eye, anyway. It's not 100% safe for your telescope and eyepiece, though. You have to make sure that there is only glass and metal--no plastic--in or near the light path, for one thing, or else something might actually melt. In my opinion, just start with the AstroSolar filter (if you can find one, with the two solar eclipses coming soon). It's only like ~$60 for your 80mm refractor, and will give you fine, safe views for both your eye and telescope. If it'll make you feel safer, you could tape the filter to the dew shield, although that shouldn't be necessary.
In most PSTs I've used, I did indeed had to tune the etalon to be able to view everything, and not all at the same time. There is also a "sweet spot" where contrast and detail are at their best. In my PST, however, I can see everything all at once with no tuning or noticeable sweet spot. I'm not here trying to brag, especially since I merely stumbled into buying this exceptional PST, sight unseen (but for a very good price), by pure, dumb luck. I'm just pointing out that some PSTs are considerably better than others. I presume that the tremendously more expensive solar scopes from Coronado are more consistently of high quality (at least I hope they are). With the entry-level Coronado PST, it's a real crap-shoot as to what level of quality you'll get.
Hi Ed, and thanks for the review. I have a solar filter for my 8se. Though it may not be the best application for solar, i can see the upcoming eclipse next month. Anything to give my 8se double duty is a win win.
Hi Ed. Always enjoy your reviews, since the beginning. I bought a Daystar Quark last year, very impressed, though the only h-alpha I’ve tried. It’s a “bit” pricier than the PST but relative to other solar scopes I find it to be a deal. Great results in my Televue 85.
Don’t you think you should mention the “rust” issue? I had to send mine back twice when the coating on the objective degraded. The second time Meade obscured the issue by adding a small filter to the scope’s interior where it couldn’t be seen. That rusted too, and I replaced it with a filter from a third party. The local observatory has a PST with an objective so rusty that the sun is really dim through it. I would be surprised to find any used PST that wasn’t either repaired, maybe more than once, or rusty to the point of uselessness. These things are notorious.
This is why I don't recommend the PST anymore. I have owned several, and half of them had bad ITF filters. The rust on the objective I think has been fixed, but the ITF failure has been reported many times.
The 3rd party vendor solution for the rusting problem is cheap and easy to implement. Also, there has been no rusting on this new lens in the 3 years I have had it. A great buy with that caviat.
I have a white light solar filter for my SCT and am ordering a H-Alpha eyepiece filter. Hopefully this will let me see more interesting views of the sun.
My caution about the PST is that they are well known to have ITF filters that fail. A replacement costs about $125. I have owned several used PSTs and half of them had ITF filters that had failed. I have owned Lunt telescopes and have never had an ITF filter fail.
@@edting It is hard to know whether or not PSTs of recent manufacture have this issue but for people shopping on the used market, it can be a major problem to know if the ITF is failing and many sellers may not be willing to open the body or remove the eyepiece holder to check. It is something that someone in the market for a used PST should know. The good news is that the aftermarket replacement is sealed around the edge and should last far longer.
I bought my first telescope last week. A Bresser Messier 8” Dobson. Still waiting on it tho but it comes with at solar filter too. Can we trust they are good enough or should i invest in a better one maybe? Well explained as always Ed, keep up The good work👍😊
I would make sure your solar filter is secure with some tape. You don't want to accidentally touch it in some way. It's the Sun, better safe than sorry... Clear skies!
Im Getting More And More Involved With Solar Viewing,And Have Just Recently Switched From My 6se,To My 72ed,I Can See More Detail Now,Im Starting Small.I Dont Care For The White Light Filters At All,And Would Never Be Able To Do A Solar Scope Justice😂l Would Love One,But As My Dad Said,Money Doesnt Grow On Trees,lol..Great Video Ed,Thank You,God Bless And Clear Skies🙏🏻❤️🔭✨🌏
Great review Ed another thing to consider with Coronado PST's is the differing quality you get between each scope, the first PST I had was ok but I always found the image to be very dim when viewing. Also tuning the etalon to see the proms was sometimes challenging to so I'd say that scope was just ok. I got myself another one with a CaK Pst & viewing through the second PST was much brighter making the scope itself much easier to live with & I still own that one. Obviously the CaK cannot be used visually but holds it's own when imaging the Sun. I do have the Lunt 35 to which again has a different viewing experience to either of the PST's with it being brighter still but imaging with it was much more fiddly with the helical focuser. I will say I did view the Sun with 102 Lunt a few years ago & that made all the solar scopes I've owned look like toys in comparison but then I don't have 5K plus to own one either.
That's true, all of the PSTs I've ever looked through have presented noticeably different views. I consider myself lucky as hell to have apparently stumbled upon the best PST in existence when I bought one for myself. I never have to tune my PST, I just leave it at the best setting, and I see prominences and surface detail clearly all at once over the entire image. If it even has a "sweet spot" I have never been able to notice it, and I've tried. Other PSTs most definitely and obviously have a sweet spot, which is sometimes circular and sometimes more like a band. And if I want to see everything there is to see, I have to play with the tuning ring. I would guess, based on my own experience and that of many others anecdotally, PSTs like the one I have are extremely rare. In fact, it's the only one I know of. These scopes are definitely a crap shoot when you buy them. Pretty much all of them work, but some work much better than others, and finding one like mine is far, far from the norm. I'd expect that the consistency and quality of the far more costly solar scopes from Coronado would be much higher. The PST is really just meant to get people hooked, and for all of its issues and flaws, it does a pretty good job of that. It worked on me, although my particular PST is so good that I haven't even thought of upgrading.
@@rbrtck The one I have now is much better tuned it once & now I don't ever have to touch it again, it did come with a double stack for it but to be honest I can't see any benefit using it other than make the Sun look darker, also it causes uneven illumination so I generally don't use it. Also there's earlier PST's that suffered with rusty objectives which I think now has been sorted but there are a few scopes out there that still suffer have it as either owners don't realise it or just haven't bothered to get them repaired so always a good idea to have a look there if buying second hand. I'd still say like Ed says recommend buying one, but if second hand try before you buy & have a good look at it first.
@@dumpydalekobservatory That's true, although even later (and I believe current) PSTs still have a "rust" issue with the internal ITF. This is an energy rejection filter mounted at the base of the eyepiece holder. It's not the ultra-red 5mm blocking filter right under the eyepiece that you can easily see, it's a reflective filter underneath that and just above (optically immediately behind) the pentaprism. You have to disassemble the scope to get a look at it. I believe that the early PST objective lenses all had energy rejection (UV and IR) coatings (as they should) that eventually "rusted" due to exposure to moisture and/or oxygen from the sides, where they leaked under the protective top layer. This was exacerbated by use, since things heat up when you're observing the Sun, which eventually compromises the seal (seems to be the case because the "rust" grows from the edge toward the center). Coronado (now owned by Meade) eventually gave up on this configuration and replaced the objectives with regular achromat doublets. That "solved" this issue for the objective, but the energy rejection was still needed for eye safety, so that was moved to an internal ITF (the one I mentioned above), which is similar to the original objective lenses, and similarly can "rust" over time, especially with a lot of usage and exposure to a humid environment. Fortunately, this gradual failure mode is fail-safe, meaning that a "rusty" ITF still blocks UV and IR just as well as ever, but it gradually loses the ability to transmit all other wavelengths, including H-alpha, which ruins the image. And obviously, moving the energy-rejection filter to near the end of the optical path means that the etalon, collimating lens, pentaprism, and other optics are now all exposed to the full power of the Sun, which is not good for them (especially the critical, all-important, rather delicate, unique-to-solar-scopes etalon). This design change did reduce the number of repairs Coronado had to make because most people can no longer see the problem, so they aren't aware that there even is one! 🙄 The image just keeps getting worse, and their etalon might be suffering, too, from all of the heating and cooling cycles. Fortunately, there are replacement ITFs available. A similar but better one is offered by Maier for about $75 (the last time I checked). It's more robust and higher quality, but is of a similar design and technology as the OEM ITF, so it's probably susceptible to "rusting", as well. There is also a substitute from BelOptik that costs like three times more, but is based on completely different and far more robust technology, and should be a permanent solution. My PST has an internal ITF, but so far I haven't had to replace it yet, even after frequent use for many years. I think it helped that I made my own energy-rejection filter that I screwed onto the front of the telescope as soon as I bought it. Well, I didn't make it, I just screwed on a Hoya 52mm UV/IR-cut filter and a Hoya #25 (Wratten) red filter that I bought used (but in perfect condition). These are camera filters, but they work great with the PST, and together they reject everything except for visible red light, before it even enters the scope (as it should be).
I'd love to hear some more about this "rust" problem I hear about these scopes getting... I've been debating getting a 40mm Lunt, but I'm a poor 'ol farm boy who's usually forced to buy used and the Lunt just doesn't come up very often. I do see lots of PST tho, so have been considering one of these instead. That's until I started noticing ads with "no rust" or "has minor rust issue". I haven't really researched about the problem or possible corrective actions but it did give me pause until I figure out what possible issues there may be.
I’ve heard the later PSTs made in Mexico aren’t as susceptible to it, the early US made ones seem to be more prone - or it could be that they’re just older in general and thus rust sooner because they were made longer ago 🤷♂️
One thing that was not highlighted was the 'rust' issue. Do the newer models suffer from it? and what should the end user do to protect it or prevent it, if out of guarantee/warranty?
There is still a "rust" issue with the internal ITF (a filter) that isn't readily seen without disassembling the PST. This can be fixed with a replacement part (one of which is more costly but permanent) somewhat easily, but it's still an issue.
Oh, and as for prevention, I've used my PST regularly for years now, and have had no "rust" issue with the internal ITF thus far. I couldn't say for sure, but possibly this was in part because I screwed 52mm UV/IR-cut and Wratten #25 red filters onto the front, as a makeshift energy-rejection filter. They're both camera filters from Hoya, and I bought them used (in perfect condition), so they didn't cost much, and far as I can tell, they don't noticeably impact image quality. In any case, it's generally good practice to keep as much energy away from the delicate etalon as possible, and more costly solar telescopes all have energy-rejection filters on the front instead of a smaller (and therefore cheaper) one inside like the PST. Ironically, the PST could use one even more because it has a tiny 20mm etalon that receives light that is concentrated from a 40mm objective lens (four times its area!). You don't have to do this, but it makes me feel better, and maybe it actually helps.
I think the Daystar Hydrogen Alpha filter is an interesting alternative. Even though it is currently priced at $1,295, you can safely attach it to say an 80 mm APO refactor, and use your equipment like a dedicated solar scope. That might be a topic for another video. And notice that you get four times the light gathering capacity of the 40 mm Coronado. Here is another suggestion: why not give a preview of your next video, like a coming attraction. That might build an audience. Always enjoy your reviews, thanks
I'm trying to get my hands on a Quark. The issue with doing a "coming soon" clip is, three years from now when people are viewing this stuff out of order, it may not make any sense.
@@edting I plan to get a Quark Chromosphere model when we move to a house with a bigger yard, hopefully later this year. Except for DayStar I find the solar telescope market to be out of my price range.
@@edting One question: why is densely settled United Kingdom doing something about Light Pollution while the Eastern US is doing nothing about it? Someone at the top in the UK is taking an interest and they must have the means to solve the problem. With the equipment that we have today, everyone should be able to enjoy Astronomy.
I made my own solar finder a small PVC tube with a paper target at the back it works well A simple question what camera do you use for that colour image or did you use black and white and false colour it I have a great deal of trouble with my Lunt taking pictures
I used the ASI120MM. Yes, it's a monochrome camera. I added the color afterwards to simulate what I saw in the eyepiece. Keep at it. I find solar imaging to be quite difficult.
Great video! What's the best way of checking one after purchasing it second hand? I mean, making sure it is safe before putting our eyeballs into the eyepiece? Thanks!
Ed what are your thoughts about getting an h-alpha filter for your eyepiece, and using that in combination with (or without) solar film? I have a 6" Thousand Oaks filter and a small sheet of film that I use for my finderscope, but they can really only show sunspots as black on white, and would love to see corona's and details that the H-Alpha allows. Thanks! Jay in Allen, TX
This is safe to do if and only if you use the certified solar film on your telescope's aperture, not just in the eyepiece, of course. But if you're thinking about using a narrowband H-alpha *nebula* filter screwed onto your eyepiece in addition to that, then there is no such filter that has a bandpass nearly narrow enough to enable you to observe prominences and surface details that an H-alpha *solar* telescope like the PST can reveal. That requires multiple filters of several types plus an etalon to accomplish. So there is no point to doing this (except for turning the Sun red), if that's the idea you have in mind. Alternatively, there is the DayStar Quark, which lets you view the Sun's features in ultra-narrowband H-alpha on a regular telescope (within certain limits), just like in a solar telescope. But it has some limitations to balance out its high value for allowing larger telescopes to be used for a relatively low price. And as for the Sun's corona, there really isn't a way to view that unless the Sun's entire disk is occulted by something in space. Here on Earth, the only way most people ever get to directly view the corona is during a *full* solar eclipse by the Moon (no telescopes or filters needed); by the way, prominences are also often visible at this time, as long as the Moon doesn't block them. Telescopes in space can image the corona by occulting the Sun's disk with an object (like a metal plate). But you're not going to see it in your telescope on Earth just any time you want, unfortunately. Well, if you're at high altitude, like the peak of a tall mountain, and use a coronagraph/coronameter with a polarizer, maybe you could get a view of the Sun's corona, but it's probably not going to work from your backyard, put it that way.
The Daystar Quark can be used for that, but you have either to stop down your telescope (only suitable for refractors) or to use an ERF in front of it (can work with reflectors, but is expensive). Using a white light solar filter with the Quark will not work and using only the Quark on a reflector might damage the secondary. For observing the corona you need a coronagraph and a location with extremely clear air, preferable on a high mountain.
The image is made at a very specific frequency, so the objective is likely just a singlet lens. There is no CA because there is only one color to see :)
Those who have taken apart and modded the PST say that the objective lens is a cemented doublet that appears to be optimized for H-alpha viewing (some say, but I don't know about the latter). While chromatic aberration is, as you pointed out, not an issue, and spherical aberration is not an issue at 40mm and f/10, there are still off-axis aberrations such as astigmatism and coma to correct, and for that purpose, one or more additional lenses are required. There are some H-alpha telescopes that have singlet objectives, but they have additional matched lenses later in the optical path that correct aberrations while serving other purposes. Lens design is not all about chromatic aberration.
@@rbrtck The field of view is by definition only 1/2 a degree (diameter of the Sun) so coma is a non-issue even with a singlet lens. As long as the singlet is well made SA will also not be an issue, particularly since it will be a very shallow lens at f/10. Such a lens as a member of an achromat would stretch to near f/20. I see no reason to use anything but a singlet.
@@ultrametric9317 Maybe it was even cheaper and easier to source a generic, mass produced 40mm cemented achromat doublet (and add coatings to it) than an appropriate singlet, and we got better off-axis correction and maybe even very slightly better on-axis correction (however insignificant or unnecessary these might be) as bonuses. It depends on what one finds on the market. I'm just guessing in the case of the PST, but there could be valid rather than pointless, thoughtless reasons. Possibly. 🤷
Don't buy that thing. Awful. They didn't get anything right. There's a reason those things are being blown out at Costco, B&H, Amazon, and others. If you want an Explore Dob, get the new First Light series.
@@ruud9767 Good point. While spherical aberration is not an issue at 40mm and f/10 (although it would be with larger apertures and faster focal ratios), there are still off-axis aberrations such as astigmatism and coma to consider. Some dedicated solar telescopes do have singlet objective lenses, and in those cases, off-axis aberrations are corrected by additional matched lenses farther along the optical path. For the entry-level PST, it was easier and probably cheaper to use a cemented achromatic doublet. This also has the advantage of correcting most aberrations before they reach the etalon, which is mounted behind the objective lens (and some other lenses, like the collimating lens). In larger, higher-end H-alpha scopes, the etalon is preferably mounted in front of the objective lens (but behind the energy-rejection filter, of course), which makes it more effective at what it does. This is not done in the PST and similar scopes because the etalon is smaller than the objective lens in order to reduce its cost. An achromatic doublet also does not require customized optics--it does a good enough job of correcting aberrations for a low-end solar telescope, and it is pretty much a standard, drop-in solution. Higher-end scopes can have higher-end, more optically customized designs to gain the subtle but noticeable advantages of using a singlet objective lens and front-mounted etalon.
@@ruud9767Correct, there are spherical aberration and coma, and one non-aspherical lens cannot even remove the first one. Btw., the achromat can only be really well corrected for spherical aberration at one wavelength, usually the e-line of mercury.
@@MikeLikesChannel This is not because they were made in the US, per se, but because these were made before the "rust" problem with the objective lens was fixed (sort of--more like moved). The other internal "rust" problem is still a thing with PSTs in general, specifically with the ITF (induced transmission filter), although it is harder to notice because it is normally hidden from view. This problem gradually degrades the image as it gets worse over time. My PST has always been protected with a makeshift energy-rejection filter (a 52mm Hoya UV/IR-cut filter and a Hoya #25 red filter that I screwed onto the front), and stored in a relatively dry environment, so I have not noticed any image degradation or "rust" on the ITF after years of use, but for when it inevitably happens, at least there are some quality replacements available. One is another ITF from Maier that has better specs and should last longer, and the other is a different type of filter from BelOptik that gets the same job done. The latter costs about three times more but is very robust and stable, and should practically never "rust" or otherwise degrade.
My mom must have told my dad not to look at his Sun because never came back, anyway why do solar scopes have such perverted names Coronado- similar to cornhole and Lunt not even going to go into that one.
I keep window shoping these.. and getting agrivated with the price.. It's madness you could pay for someones surgery or something! It always turns into.. "how to make your own etalon" Seems like it's wizardry, everyone is just a consumer and no one cares to know how this stuff works!
1) Due to the cost of filters, even a completely DIY with parts you have laying around is still going to cost you about the same as a used PST. 2) If you screw up, you burn your eyeball. As in actually burn it -- search UA-cam for the astronomer lighting a pig eye on fire by holding it in front of an unfiltered telescope.
I have one and I love it. Solidly built, easy to carry and easy to use.
$350-500 used is the sweet spot for the PST. I use mine for outreach at street festivals and observatory events. For that purpose it’s all you need. The average person isn’t going to care if it’s double stacked or at a larger aperture. They’ll see the sun in H-alpha and that’ll be a memory they keep.
If you plan to image and be outside every day. Go nuts. Also remember if you live in the snow belt, we go weeks at a time barely even seeing the sun. So the value proposition changes if you live in the sun belt too 😆
Bought a brand new PST in 2018 for $500. It was on sale. Mounts very nice on Televue mount. Kids like seeing the Sun "on fire." Thanks for the video.
Thank you Ed for taking the time to keep us well informed and entertained. Reliable information is getting hard to come by... You have taught me so much! Clear skies 😊
As opposed to 'Impersonal Solar Telescope'. You know, the one that ignores you when you say 'hello' and doesn't return your phone calls.
I bought my PST about one year after they first came out. Since then, it has been my most-used telescope by far as it sits ready to grab-and go all the time. The scope was de-rusted twice by Coronado/Meade and the changes implemented on it, as in the newer models, make it a lot better than it was. I have the third party solution for the rusted lens and it was cheap and easy to install. I have owned 60mm and 90mm Ha telescopes in the past and the one that is still with me is the venerable PST.
I've had my PST for 11 years and as a fairly casual sun observer, I don't see myself needing a more expensive solar scope anytime soon. I love the thing.
Bingo. I think too many people are in a rush to spend a fortune on a specialty product used on solely one object. Once you say it out loud “I’m only going to look at the sun with this!” and realize competitors are asking 3-4x what the PST costs, you come to your senses 😉
I’ve had my PST (second hand) for a decade or so and I never thought about upgrading it until now. Thanks, Ed!
I had a PST for a while,. even met someone who had set up two PSTs side by side as a binocular solar telescope. I also had the original Coronado 40mm etalon and BF10 diagonal and used it on a Televue 76, a Televue 60 and a Tak 60FS. I called it my Ultraportable Solar Observatory and brought it to the NEAF Solar Star Party for years. When I retired, I wanted something more but the prices had skyrocketed. I have a Televue 85 that I got the Lunt 60 etalon and BF1200 diagonal for and I have been enjoying the much improved views. I don't care for double-stacking, I've tried that with a 60mm Lunt scope years back and I prefer the single-stack image. It is on an alt-az mount with slow motion controls so I can just carry it outside quick, use the Televue Sol Searcher to find the sun in an instant and enjoy a lengthy observing session. But the PST is not a bad way to break in. At today's prices, the advice to go used is a good one, save some now and then spend the rest on a better system if your interest grows.
I’ve had one of these for years. I bought it about a month before Meade bought Coronado. I love it and it piggy backs on whichever telescope I have the white light filter on. Makes a great combo.
Thank you for this! Nothing like an honest, *informed* opinion on very pricy items! Cheers!
I have a pst single and while it doesn't get much use, it's certainly more interesting with the solar maximum we're in... For the upcoming eclipses I have some white light film filters for my 6" and my c130, but I found that I needed an additional yellow - orange filter and adjustable polarizing filterto get the color and brightness closer to what my eyes/brain expect. I do like the better resolution provided by the bigger aperture for visual! I didn't have an eyepiece cam until this year so now I can give that a try on both rigs. On a smaller scope I'll be using a herschel wedge with a CaK filter on another refractor to try imaging with too. Getting pretty excited about that! 😁 To much to try and enough time... (as usual)
Great video, Ed! Seeing the solar prominences during totality yesterday in my 8 inch Dobsonian made me want to get a dedicated solar viewing scope.
I just had my focuser repaired. Mine is quite old. Cost was about $200 and was worth it because they went over it and replaced a filter as well. Took about two months including transit time to Canada.
I love every review of yours. I wish i could watch a few everday but i understand it takes alot of effort to bring such a quality review for us to watch.
Thanks for the trouble you go through.
Regards
Thanks, I put a lot of pressure on myself to get it (at least sort of) right.
The only way I have observed the sun is eyepiece projection. A cheap 10mm eyepiece, bounced off a first surface mirror and a homemade screen, always completely safe.
Perfect, thanks Ed!
I bought a second-hand SolarMax 40, which it turned out the owner was selling because the internal filters were degrading (although not noticeably to me at the time). I later bought a second-hand PST which I still have, and use double-stacked with the etalon from the other telescope. That was still OK and conveniently screws into the front of the PST, although the image is pretty dim with the double stack.
Imaging with these scopes is difficult, and in my experience requires you take multiple images (or videos) and mosaic them together to get a full-disc image. The illumination is far from uniform across the field due to the small exit aperture, so flat-fielding each image is essential before joining them into a mosaic. If done carefully the result can be very pleasing, but it's a lot of effort and requires a level of skill that not all amateurs possess.
I sometimes use the PST without the extra etalon just to look at the Sun in H-alpha, which is easy and the views are good. I would regard the PST as a very useful entry to solar viewing in H-alpha. If you decide it's not for you, or if it is but you want to upgrade, you'll probably be able to find a buyer for the PST without too much trouble.
I use solar film on my 100mm f5 Helios achromatic refractor. Using a green filter highlights the sunspots and allows imaging with a camera.
Hydrogen alpha filters or calcium filters can easily be attached.
An IR cut filter is essential for imaging.
A friend of mine had the PST and he liked it, but said forget about using much higher than 50x magnification for close ups because contrast starts to get a little hard to maintain. The double aperture rule doesn't apply with these and it being an achromat explains it. I got the 50mm Lunt for under a $1000 and am happy with it.
Haha funny enough, I just bought one of these right before you posted this. I've been using and abusing that little PST since it arrived.
Thanks for another great review. I have a Lunt 40mm solar scope and have obtained surprisingly good whole disc images using a Player One Apollo Mini camera.
I've been meaning to try out the Player One cameras...
Great video, Ed! I went back and forth the PST and the Lunt 40 and ended up settling for the Lunt 40 and I'm happy with it. They also just released a double stack filter for it. it comes with a Tele Vue Sol Searcher which is super handy.
Really useful review, Ed!
Thank you, I put a lot of effort into these videos.
I'm interested in doing solar photography and have yet to figure out which one to get. This was a great video to give me an idea as to where I need to start.
I still find it amazing that more astrophotographers don’t image the sun, it doubles the utilization of your gear and keeps you busy during the day.
I think it’s because of a thing called a job in the day, yeah I’m gonna go with that 😄👍🏼
Some PSTs, like mine, have a very bright image--bright enough that even during the middle of the day, my eye takes a minute or two to adjust to the brightness. I do recall observing through other PSTs, and yes, they had much dimmer images (and they were not double-stacked). The image in my PST is also more contrasty and detailed than I remember in other PSTs. Perhaps they suffered from the "rust" issue (either the objective lens in older PSTs or internal ITF in newer ones), which among other things, does dim the image. The 40mm aperture in the case of my particular PST (and that of some others I've heard about) is more than adequate in terms of light gathering. And because I'm getting such great views, I can't imagine that too much light is getting through--it's more like all the light that should be getting through actually is getting through.
It's true the aperture is too small but not only that but the focal length is very short resulting in a small image of the sun. And I had to use a higher power eyepiece but doing so dim the sun image and made it less contrasty. Also I didn't hear you mention the problem with the filters having a rust issue, and many had to be fixed, I would be wary of that on the used market getting a rust personal solar telescope.
Maybe I didn't do something right but I sold my PST and wouldn't buy another one, they're just too small for a bright usable image, IMO.
From everything I have gathered online (and the bias of personally owning a Lunt), the Lunt 40 is a step above the PST, with a better bandpass (0.7 vs 1.0 Angstrom, lower meaning more contrast in the h-alpha features) and able to focus cameras without additional modifications. At a cheaper price too, so I'd recommend people research both.
I got the Lunt 50mm. It’s a work of art. Way better than the pst. Came with a hard case, pressure tuner and I upgraded to a Feathertouch focuser. Take away the focuser upgrade and it’s still about the same price. I feel like Lunt keeps their entry prices low because they know you’ll upgrade eventually and go with another Lunt. Customer service is unmatched as well.
For a long time the Lunt 40 wasn't even available new. It had been discontinued a long time ago and was brought back fairly recently. I bought my PST (barely) used for cheap during that time and I haven't regretted it, but I'm glad the Lunt 40 is back on the market.
I’d never suggest a double stacked PST, at that cost… it’s too much. Still, a used single stack PST for $350-500 is a stellar (all puns intended) deal!
Wow how do you manage to focus a camera on a lunt I have only been able to do that with a BW camera
Timely, thank you Ed! I have been considering getting into solar observing and feel like anything short of h-alpha would leave me wanting more.
I have stayed away from filters and used equipment since there is basically no scope for error (safety wise) and I just can't trust pre-owned equipment for this. Will look into the PST!
I agree that anything less would leave you wanting more. That said, white light solar filters offer a different and, to my eye, clearer view of sunspots, as well as granulation, which you can't see distinctly in an H-alpha telescope. Granulation is easier to see with a medium/deep green filter (on the eyepiece), by the way, in addition to the solar film on the aperture.
@@rbrtck Thank you for your perspective! Am I correct in understanding that in buying a dedicated h-alpha scope such as this one (or the Lunt 40/50), there will be no way to see the sun in white light? If so, perhaps I can augment that purchase with filters for my existing scopes to achieve what you said. In refractors, I currently have a StellarVue SV80ST and ES ED127. Do you have filter recommendations for these? I am generally concerned about safety so the highest quality/reliability would be ideal.
@@mxms533 Correct, as dedicated H-alpha solar scopes, the Coronado PST and Lunt LS40THa/LS50THa can only be used to observe in H-alpha. Between them, I only have experience with the PST, and luckily for me, the PST I happen to own is truly exceptional--by far the best I've observed with. It's kind of ridiculous, actually, because it has no discernible "sweet spot", and I don't have to keep tuning it to see everything--I see everything at once over the entire image of the Sun very clearly. I haven't adjusted the tuning in years. The other PSTs I've used were decent, but they weren't like the one I have, and PSTs seem to have a lot of issues in general. If I had to guess, based on design, specs, and anecdotes from others, I'd say that you'll probably have better luck with one of the Lunt solar scopes. By the way, the basic Celestron or Meade 8-24mm zoom eyepiece goes great with the PST, and I can't imagine why it wouldn't be the same for the Lunt scopes, as well. I don't use that eyepiece for observing the night sky (I have better eyepieces for that), but it just works so well for H-alpha (as well or better than many of my otherwise superior eyepieces), in my experience, and gives you many magnifications in one package, of course.
As for white light, to be honest, many people seem to abandon or mostly abandon observing the Sun in white light once they've made the move to H-alpha. I still observe in white light occasionally, when there are some nice, big sunspots I want to get a good, detailed look at, but the vast majority of my solar observing is done in H-alpha with my PST. You can see sunspots in H-alpha, but their details get swamped by everything else that is going on in the image, and the 40mm aperture is another limiting factor. So what I said about the advantages of white light observing is true, but I just wanted to offer a bit more perspective. If you're still interested in this, then your refractors are of course more than good enough for this purpose. As a personal preference, I would recommend a Baader AstroSolar visual white light solar filter. This is based on image quality, primarily. I made my own filter cell with the film that fits very tightly for safety, but Baader offer their own cells with the film installed (the film doesn't even have to be flat, and the image quality is superb regardless, in my opinion). I can't vouch for their cells myself, but they are a reputable manufacturer and their filter cells generally receive excellent reviews.
@@mxms533 Here is some additional information for completeness. An economical way to observe the Sun in H-alpha using larger, regular telescopes is to buy the DayStar Quark. While it has some limitations in comparison to dedicated H-alpha scopes, at about $1300, it's a lot cheaper than buying a larger H-alpha scope, and with larger apertures than the 40-50mm of the entry-level H-alpha scopes, you get better resolution, of course. It's an interesting and popular alternative, and you get to use your current very nice refractors and all that comes with this. I highly recommend using a front-mounted energy-rejection filter with this setup, by the way, to protect your telescope and the Quark from excessive heat. If you're interested, I can go into more depth, and of course you might want to look this up for yourself, as well.
Regarding white light observing, I recommended the Baader AstroSolar visual film filter because it is both rather economical and of very high quality in terms of image. It also actually presents the Sun in white light, as in it looks white and is full-spectrum. Other polymer film-based filters color the Sun quite a bit (typically orange), and do not offer nearly the same image quality, in my opinion. But there are some alternatives. There are glass filters (like the one that Ed showed) that likewise present the Sun as white (maybe some don't, so check) and provide a high quality image. But they are heavier, quite a bit more expensive, and in my opinion aren't quite as good optically as the AstroSolar film.
Another alternative (the last one for direct viewing, I think) is to use a Herschel wedge/prism. This old technology actually provides the highest white light image quality and most faithful representation of the Sun's spectrum, albeit it has some drawbacks, as well. One drawback is cost, as it is the most expensive solution, and not everyone is willing to spend so much on observing the Sun in white light, unless they are a sunspot connoisseur/fanatic (not that there is anything wrong with that, of course) or want to take the highest quality photos in white light. Another drawback is that most of the Sun's energy is blasted out of the device (watch out!), which tends to keep getting warmer anyway; some even absorb the heat with a heavy heat sink instead. For those who want only the best white light image quality, the Herschel wedge is where it's at, no question about it, but for most people the Baader AstroSolar film is the best fit, as it works nearly as well for a small fraction of the price and has none of the drawbacks (and it spares your telescope from the heat of the Sun by reflecting nearly all of its energy away before it enters).
Finally, there is the even older method of solar projection (used by Galileo and his contemporaries, with Thomas Harriot probably being the first among them all). That's still great for observing solar eclipses today, and you can see sunspots, although I think you are going for direct views instead for greater detail. I just thought I'd mention it, both for completeness and because of your emphasis on safety. There is no safer way to observe the Sun in white light, besides using a camera instead of your eye, anyway. It's not 100% safe for your telescope and eyepiece, though. You have to make sure that there is only glass and metal--no plastic--in or near the light path, for one thing, or else something might actually melt. In my opinion, just start with the AstroSolar filter (if you can find one, with the two solar eclipses coming soon). It's only like ~$60 for your 80mm refractor, and will give you fine, safe views for both your eye and telescope. If it'll make you feel safer, you could tape the filter to the dew shield, although that shouldn't be necessary.
In most PSTs I've used, I did indeed had to tune the etalon to be able to view everything, and not all at the same time. There is also a "sweet spot" where contrast and detail are at their best. In my PST, however, I can see everything all at once with no tuning or noticeable sweet spot. I'm not here trying to brag, especially since I merely stumbled into buying this exceptional PST, sight unseen (but for a very good price), by pure, dumb luck. I'm just pointing out that some PSTs are considerably better than others. I presume that the tremendously more expensive solar scopes from Coronado are more consistently of high quality (at least I hope they are). With the entry-level Coronado PST, it's a real crap-shoot as to what level of quality you'll get.
Hi Ed, and thanks for the review. I have a solar filter for my 8se. Though it may not be the best application for solar, i can see the upcoming eclipse next month. Anything to give my 8se double duty is a win win.
Hi Ed. Always enjoy your reviews, since the beginning. I bought a Daystar Quark last year, very impressed, though the only h-alpha I’ve tried. It’s a “bit” pricier than the PST but relative to other solar scopes I find it to be a deal. Great results in my Televue 85.
I'm trying to get my hands on a Daystar Quark for review.
@@edtingid be glad to loan you my quark For review, I’d you’d like. I’m in Massachusetts, fairly local.
Don’t you think you should mention the “rust” issue? I had to send mine back twice when the coating on the objective degraded. The second time Meade obscured the issue by adding a small filter to the scope’s interior where it couldn’t be seen. That rusted too, and I replaced it with a filter from a third party. The local observatory has a PST with an objective so rusty that the sun is really dim through it. I would be surprised to find any used PST that wasn’t either repaired, maybe more than once, or rusty to the point of uselessness. These things are notorious.
This is why I don't recommend the PST anymore. I have owned several, and half of them had bad ITF filters. The rust on the objective I think has been fixed, but the ITF failure has been reported many times.
The 3rd party vendor solution for the rusting problem is cheap and easy to implement. Also, there has been no rusting on this new lens in the 3 years I have had it. A great buy with that caviat.
I have a white light solar filter for my SCT and am ordering a H-Alpha eyepiece filter. Hopefully this will let me see more interesting views of the sun.
I wouldn't do that unless you have a suitable companion full aperture solar filter. Please please be careful out there!
@@edtingThe full aperture solar filter must be some type of ERF, as a white light solar filter would reduce the light too much.
If the view in double stack modus is too dimm, maybe you can try a brighter ITF filter such as the beloptic ITF .
My caution about the PST is that they are well known to have ITF filters that fail. A replacement costs about $125. I have owned several used PSTs and half of them had ITF filters that had failed. I have owned Lunt telescopes and have never had an ITF filter fail.
Yes, thank you. I should have mentioned that.
@@edting It is hard to know whether or not PSTs of recent manufacture have this issue but for people shopping on the used market, it can be a major problem to know if the ITF is failing and many sellers may not be willing to open the body or remove the eyepiece holder to check. It is something that someone in the market for a used PST should know. The good news is that the aftermarket replacement is sealed around the edge and should last far longer.
The last time I pointed a scope at the sun was the Venus transit... so that's been a few yrs. Given that I can't justify one of these scopes at all!
I bought my first telescope last week. A Bresser Messier 8” Dobson. Still waiting on it tho but it comes with at solar filter too. Can we trust they are good enough or should i invest in a better one maybe? Well explained as always Ed, keep up The good work👍😊
I would make sure your solar filter is secure with some tape. You don't want to accidentally touch it in some way. It's the Sun, better safe than sorry... Clear skies!
Im Getting More And More Involved With Solar Viewing,And Have Just Recently Switched From My 6se,To My 72ed,I Can See More Detail Now,Im Starting Small.I Dont Care For The White Light Filters At All,And Would Never Be Able To Do A Solar Scope Justice😂l Would Love One,But As My Dad Said,Money Doesnt Grow On Trees,lol..Great Video Ed,Thank You,God Bless And Clear Skies🙏🏻❤️🔭✨🌏
Great review Ed another thing to consider with Coronado PST's is the differing quality you get between each scope, the first PST I had was ok but I always found the image to be very dim when viewing. Also tuning the etalon to see the proms was sometimes challenging to so I'd say that scope was just ok. I got myself another one with a CaK Pst & viewing through the second PST was much brighter making the scope itself much easier to live with & I still own that one. Obviously the CaK cannot be used visually but holds it's own when imaging the Sun. I do have the Lunt 35 to which again has a different viewing experience to either of the PST's with it being brighter still but imaging with it was much more fiddly with the helical focuser. I will say I did view the Sun with 102 Lunt a few years ago & that made all the solar scopes I've owned look like toys in comparison but then I don't have 5K plus to own one either.
That's true, all of the PSTs I've ever looked through have presented noticeably different views. I consider myself lucky as hell to have apparently stumbled upon the best PST in existence when I bought one for myself. I never have to tune my PST, I just leave it at the best setting, and I see prominences and surface detail clearly all at once over the entire image. If it even has a "sweet spot" I have never been able to notice it, and I've tried. Other PSTs most definitely and obviously have a sweet spot, which is sometimes circular and sometimes more like a band. And if I want to see everything there is to see, I have to play with the tuning ring.
I would guess, based on my own experience and that of many others anecdotally, PSTs like the one I have are extremely rare. In fact, it's the only one I know of. These scopes are definitely a crap shoot when you buy them. Pretty much all of them work, but some work much better than others, and finding one like mine is far, far from the norm. I'd expect that the consistency and quality of the far more costly solar scopes from Coronado would be much higher. The PST is really just meant to get people hooked, and for all of its issues and flaws, it does a pretty good job of that. It worked on me, although my particular PST is so good that I haven't even thought of upgrading.
@@rbrtck The one I have now is much better tuned it once & now I don't ever have to touch it again, it did come with a double stack for it but to be honest I can't see any benefit using it other than make the Sun look darker, also it causes uneven illumination so I generally don't use it. Also there's earlier PST's that suffered with rusty objectives which I think now has been sorted but there are a few scopes out there that still suffer have it as either owners don't realise it or just haven't bothered to get them repaired so always a good idea to have a look there if buying second hand. I'd still say like Ed says recommend buying one, but if second hand try before you buy & have a good look at it first.
@@dumpydalekobservatory That's true, although even later (and I believe current) PSTs still have a "rust" issue with the internal ITF. This is an energy rejection filter mounted at the base of the eyepiece holder. It's not the ultra-red 5mm blocking filter right under the eyepiece that you can easily see, it's a reflective filter underneath that and just above (optically immediately behind) the pentaprism. You have to disassemble the scope to get a look at it.
I believe that the early PST objective lenses all had energy rejection (UV and IR) coatings (as they should) that eventually "rusted" due to exposure to moisture and/or oxygen from the sides, where they leaked under the protective top layer. This was exacerbated by use, since things heat up when you're observing the Sun, which eventually compromises the seal (seems to be the case because the "rust" grows from the edge toward the center). Coronado (now owned by Meade) eventually gave up on this configuration and replaced the objectives with regular achromat doublets. That "solved" this issue for the objective, but the energy rejection was still needed for eye safety, so that was moved to an internal ITF (the one I mentioned above), which is similar to the original objective lenses, and similarly can "rust" over time, especially with a lot of usage and exposure to a humid environment.
Fortunately, this gradual failure mode is fail-safe, meaning that a "rusty" ITF still blocks UV and IR just as well as ever, but it gradually loses the ability to transmit all other wavelengths, including H-alpha, which ruins the image. And obviously, moving the energy-rejection filter to near the end of the optical path means that the etalon, collimating lens, pentaprism, and other optics are now all exposed to the full power of the Sun, which is not good for them (especially the critical, all-important, rather delicate, unique-to-solar-scopes etalon). This design change did reduce the number of repairs Coronado had to make because most people can no longer see the problem, so they aren't aware that there even is one! 🙄 The image just keeps getting worse, and their etalon might be suffering, too, from all of the heating and cooling cycles.
Fortunately, there are replacement ITFs available. A similar but better one is offered by Maier for about $75 (the last time I checked). It's more robust and higher quality, but is of a similar design and technology as the OEM ITF, so it's probably susceptible to "rusting", as well. There is also a substitute from BelOptik that costs like three times more, but is based on completely different and far more robust technology, and should be a permanent solution.
My PST has an internal ITF, but so far I haven't had to replace it yet, even after frequent use for many years. I think it helped that I made my own energy-rejection filter that I screwed onto the front of the telescope as soon as I bought it. Well, I didn't make it, I just screwed on a Hoya 52mm UV/IR-cut filter and a Hoya #25 (Wratten) red filter that I bought used (but in perfect condition). These are camera filters, but they work great with the PST, and together they reject everything except for visible red light, before it even enters the scope (as it should be).
Thank you.
I’ll second the idea that everyone should get into solar.
Ahh Mr Ting always has a sunny disposition.
I’d also like to hear your thoughts on the Cemax eyepiece set from Coronado. They seemed to me like ordinary plossls.
I'd love to hear some more about this "rust" problem I hear about these scopes getting...
I've been debating getting a 40mm Lunt, but I'm a poor 'ol farm boy who's usually forced to buy used and the Lunt just doesn't come up very often. I do see lots of PST tho, so have been considering one of these instead.
That's until I started noticing ads with "no rust" or "has minor rust issue". I haven't really researched about the problem or possible corrective actions but it did give me pause until I figure out what possible issues there may be.
While I've heard of the rust issue, I've never experienced it myself. People are right, I should have mentioned it.
I’ve heard the later PSTs made in Mexico aren’t as susceptible to it, the early US made ones seem to be more prone - or it could be that they’re just older in general and thus rust sooner because they were made longer ago 🤷♂️
"The light gathering ability is the Achilles' heel." On the other hand, you are looking at the sun!
Ed. What are your thoughts of home observatory domes? Are they worth it?
Whether to dome or not is a personal decision! Search your soul and seek the answer...
One thing that was not highlighted was the 'rust' issue. Do the newer models suffer from it? and what should the end user do to protect it or prevent it, if out of guarantee/warranty?
There is still a "rust" issue with the internal ITF (a filter) that isn't readily seen without disassembling the PST. This can be fixed with a replacement part (one of which is more costly but permanent) somewhat easily, but it's still an issue.
Oh, and as for prevention, I've used my PST regularly for years now, and have had no "rust" issue with the internal ITF thus far. I couldn't say for sure, but possibly this was in part because I screwed 52mm UV/IR-cut and Wratten #25 red filters onto the front, as a makeshift energy-rejection filter. They're both camera filters from Hoya, and I bought them used (in perfect condition), so they didn't cost much, and far as I can tell, they don't noticeably impact image quality.
In any case, it's generally good practice to keep as much energy away from the delicate etalon as possible, and more costly solar telescopes all have energy-rejection filters on the front instead of a smaller (and therefore cheaper) one inside like the PST. Ironically, the PST could use one even more because it has a tiny 20mm etalon that receives light that is concentrated from a 40mm objective lens (four times its area!). You don't have to do this, but it makes me feel better, and maybe it actually helps.
The issue with the aperture isn't the light gathered; it's the sun after all. The issue with the aperture is the resolution.
I think the Daystar Hydrogen Alpha filter is an interesting alternative. Even though it is currently priced at $1,295, you can safely attach it to say an 80 mm APO refactor, and use your equipment like a dedicated solar scope. That might be a topic for another video. And notice that you get four times the light gathering capacity of the 40 mm Coronado.
Here is another suggestion: why not give a preview of your next video, like a coming attraction. That might build an audience. Always enjoy your reviews, thanks
I'm trying to get my hands on a Quark. The issue with doing a "coming soon" clip is, three years from now when people are viewing this stuff out of order, it may not make any sense.
@@edting I plan to get a Quark Chromosphere model when we move to a house with a bigger yard, hopefully later this year. Except for DayStar I find the solar telescope market to be out of my price range.
@@edting One question: why is densely settled United Kingdom doing something about Light Pollution while the Eastern US is doing nothing about it? Someone at the top in the UK is taking an interest and they must have the means to solve the problem. With the equipment that we have today, everyone should be able to enjoy Astronomy.
Ed, can you send me greetings? I’m from Costa Rica and I have been following you since 10 years. Nice videos
I made my own solar finder a small PVC tube with a paper target at the back it works well
A simple question what camera do you use for that colour image or did you use black and white and false colour it I have a great deal of trouble with my Lunt taking pictures
I used the ASI120MM. Yes, it's a monochrome camera. I added the color afterwards to simulate what I saw in the eyepiece. Keep at it. I find solar imaging to be quite difficult.
Great video! What's the best way of checking one after purchasing it second hand? I mean, making sure it is safe before putting our eyeballs into the eyepiece? Thanks!
Thanks for the video!
Do you think the eyepiece quality would make a difference in the image?
On this product, not so much. The PST is a budget product. If you have other scopes, you can rationalize the purchase of a high quality eyepiece.
@@edting
Sounds good, thank you!
Hey Ed. I'm curious about solar observing. Curious what your thoughts are on the Daystar Quark. Thanks.
I expect to play with a Quark within the next month or so.
The real issue is the BF5 exit hole. BF10 or BF15 are much nicer.
Ed what are your thoughts about getting an h-alpha filter for your eyepiece, and using that in combination with (or without) solar film?
I have a 6" Thousand Oaks filter and a small sheet of film that I use for my finderscope, but they can really only show sunspots as black on white, and would love to see corona's and details that the H-Alpha allows.
Thanks!
Jay in Allen, TX
Too dangerous to filter at the eyepiece alone. Easy to make a deadly (to your optic nerve) mistake
I wouldn't mess with it. Safety first, please!
This is safe to do if and only if you use the certified solar film on your telescope's aperture, not just in the eyepiece, of course. But if you're thinking about using a narrowband H-alpha *nebula* filter screwed onto your eyepiece in addition to that, then there is no such filter that has a bandpass nearly narrow enough to enable you to observe prominences and surface details that an H-alpha *solar* telescope like the PST can reveal. That requires multiple filters of several types plus an etalon to accomplish. So there is no point to doing this (except for turning the Sun red), if that's the idea you have in mind.
Alternatively, there is the DayStar Quark, which lets you view the Sun's features in ultra-narrowband H-alpha on a regular telescope (within certain limits), just like in a solar telescope. But it has some limitations to balance out its high value for allowing larger telescopes to be used for a relatively low price.
And as for the Sun's corona, there really isn't a way to view that unless the Sun's entire disk is occulted by something in space. Here on Earth, the only way most people ever get to directly view the corona is during a *full* solar eclipse by the Moon (no telescopes or filters needed); by the way, prominences are also often visible at this time, as long as the Moon doesn't block them. Telescopes in space can image the corona by occulting the Sun's disk with an object (like a metal plate). But you're not going to see it in your telescope on Earth just any time you want, unfortunately. Well, if you're at high altitude, like the peak of a tall mountain, and use a coronagraph/coronameter with a polarizer, maybe you could get a view of the Sun's corona, but it's probably not going to work from your backyard, put it that way.
The Daystar Quark can be used for that, but you have either to stop down your telescope (only suitable for refractors) or to use an ERF in front of it (can work with reflectors, but is expensive). Using a white light solar filter with the Quark will not work and using only the Quark on a reflector might damage the secondary. For observing the corona you need a coronagraph and a location with extremely clear air, preferable on a high mountain.
The image is made at a very specific frequency, so the objective is likely just a singlet lens. There is no CA because there is only one color to see :)
Those who have taken apart and modded the PST say that the objective lens is a cemented doublet that appears to be optimized for H-alpha viewing (some say, but I don't know about the latter). While chromatic aberration is, as you pointed out, not an issue, and spherical aberration is not an issue at 40mm and f/10, there are still off-axis aberrations such as astigmatism and coma to correct, and for that purpose, one or more additional lenses are required. There are some H-alpha telescopes that have singlet objectives, but they have additional matched lenses later in the optical path that correct aberrations while serving other purposes. Lens design is not all about chromatic aberration.
@@rbrtck The field of view is by definition only 1/2 a degree (diameter of the Sun) so coma is a non-issue even with a singlet lens. As long as the singlet is well made SA will also not be an issue, particularly since it will be a very shallow lens at f/10. Such a lens as a member of an achromat would stretch to near f/20. I see no reason to use anything but a singlet.
@@ultrametric9317 Maybe it was even cheaper and easier to source a generic, mass produced 40mm cemented achromat doublet (and add coatings to it) than an appropriate singlet, and we got better off-axis correction and maybe even very slightly better on-axis correction (however insignificant or unnecessary these might be) as bonuses. It depends on what one finds on the market. I'm just guessing in the case of the PST, but there could be valid rather than pointless, thoughtless reasons. Possibly. 🤷
Is this fabry-perot interferometry?
Yo Ed can you review the explore scientific 10” truss tube dobsonian?
Don't buy that thing. Awful. They didn't get anything right. There's a reason those things are being blown out at Costco, B&H, Amazon, and others. If you want an Explore Dob, get the new First Light series.
@@edting could explain why it was only $650 lol
$650, $599, bah! I've seen it on Amazon for as low as $188.
@@edting woah… that’s really cheap
That fence kills me, guy needed a string line to level things out 😂sorry.
Real ones know this so the 2nd upload
Thanks Ed. I have a question: if the telescope lets through only one wavelength, why is it fitted with an achromat?
You know, that is an outstanding question!
@@edting Possibly using two elements allows suppressing other aberrations. With four surfaces you can do more than with two.
@@ruud9767 Good point. While spherical aberration is not an issue at 40mm and f/10 (although it would be with larger apertures and faster focal ratios), there are still off-axis aberrations such as astigmatism and coma to consider. Some dedicated solar telescopes do have singlet objective lenses, and in those cases, off-axis aberrations are corrected by additional matched lenses farther along the optical path. For the entry-level PST, it was easier and probably cheaper to use a cemented achromatic doublet. This also has the advantage of correcting most aberrations before they reach the etalon, which is mounted behind the objective lens (and some other lenses, like the collimating lens).
In larger, higher-end H-alpha scopes, the etalon is preferably mounted in front of the objective lens (but behind the energy-rejection filter, of course), which makes it more effective at what it does. This is not done in the PST and similar scopes because the etalon is smaller than the objective lens in order to reduce its cost. An achromatic doublet also does not require customized optics--it does a good enough job of correcting aberrations for a low-end solar telescope, and it is pretty much a standard, drop-in solution. Higher-end scopes can have higher-end, more optically customized designs to gain the subtle but noticeable advantages of using a singlet objective lens and front-mounted etalon.
@@ruud9767Correct, there are spherical aberration and coma, and one non-aspherical lens cannot even remove the first one. Btw., the achromat can only be really well corrected for spherical aberration at one wavelength, usually the e-line of mercury.
Can you see flares moving ?
No, they move too slowly. Come back day after day and you can see changes though.
Thank you, Ed@@edting
pretty sure you shot this one a long time back and reuploaded with edits, yea? @Ed Ting I distinctly remember viewing this video, Deja Vu is strong.
Yes, I screwed up the upload a couple of months back. It should be in the description.
Roger that! Thanks @@edting for all the work you put in - makes the hbby infinitely more fun with your insights.
The Made in USA PST are the best one's
The US made ones are prone to rusting. Not good.
The best PST I have ever used, by very far, is the one I'm lucky enough to own, and it was made in Mexico.
@@MikeLikesChannel This is not because they were made in the US, per se, but because these were made before the "rust" problem with the objective lens was fixed (sort of--more like moved). The other internal "rust" problem is still a thing with PSTs in general, specifically with the ITF (induced transmission filter), although it is harder to notice because it is normally hidden from view. This problem gradually degrades the image as it gets worse over time.
My PST has always been protected with a makeshift energy-rejection filter (a 52mm Hoya UV/IR-cut filter and a Hoya #25 red filter that I screwed onto the front), and stored in a relatively dry environment, so I have not noticed any image degradation or "rust" on the ITF after years of use, but for when it inevitably happens, at least there are some quality replacements available. One is another ITF from Maier that has better specs and should last longer, and the other is a different type of filter from BelOptik that gets the same job done. The latter costs about three times more but is very robust and stable, and should practically never "rust" or otherwise degrade.
I have the Lunt 40, I think it's better. I'll throw it on a tripod with a ballhead or my skyguider pro
Good video, but that was a 'yes' that sounded a lot like 'no'.
Used tricky for many reasons. Lunt a much better company nowadays
My mom must have told my dad not to look at his Sun because never came back, anyway why do solar scopes have such perverted names Coronado- similar to cornhole and Lunt not even going to go into that one.
I keep window shoping these.. and getting agrivated with the price.. It's madness you could pay for someones surgery or something!
It always turns into.. "how to make your own etalon"
Seems like it's wizardry, everyone is just a consumer and no one cares to know how this stuff works!
1) Due to the cost of filters, even a completely DIY with parts you have laying around is still going to cost you about the same as a used PST. 2) If you screw up, you burn your eyeball. As in actually burn it -- search UA-cam for the astronomer lighting a pig eye on fire by holding it in front of an unfiltered telescope.