Excellent overview of telescopes and the strengths and weakness of each (refractor, reflector, catadioptric). This is a video I would recommend to those thinking of getting a telescope for observing the night sky.
Absolutely fantastic presentation. I'm enthralled as well as having learnt not just the how it works but why it works that way. Great upload . Thank you.
With respect to refractors (i own both refractors and Newtonians), anything above an F/8 ratio should have little to no chromatic aberration whatever magnification you use. Coatings have improved a lot over the years where they can reduce it considerably on faster F/ratios. There are also filters that can help with it but if you are cheap, just use a Yellow filter. And here's one that's rarely mentioned, not everyone sees it, even on planets like Jupiter. As for Newtonians, you will see diffraction spikes created by the spider legs on bright objects and short F/ratio Newtonians can overwhelm images in astrophotography. They also need a parabolic mirror (which increases the price) unless its an F/8 or more, though the F/ratio varies depending on the aperture size. I owned a 6inch dob but got rid of it because it never showed me anything my 90mm refractor showed me. The 90mm is easily portable, whereas the dob was heavy, very heavy. There were many nights where the refractor had a cleaner image than the dob, despite being climatized and collimated. Refractors handle the atmosphere better than Newtonians. It doesn't matter how good coatings are, even ignoring the central obstruction on a Newtonian, glass transmits more light than mirrors ever could and refractors being a closed system benefits it even more, no tube currents, nothing to effect the light path right up to the eyepiece. I am of the opinion that if you buy anything less than an 8inch dob, then it should be a refractor and i never recommend dobs to new astronomers because i have seen too many sent back because of their size. A 60mm or more refractor (Yes, a 60mm, they can show a surprising amount of stuff in the night sky like the full Messier catalogue, Jupiter and Saturn's rings and the moon) but a 70mm or more is better but refractors can get heavy after 102mm aperture, or at least the tripods can. Couple of pointers: Plastic lenses aren't always that bad, 62degree Aspheric's are hard to beat for the price. If a telescope comes with an eyepiece like H20mm, SR4mm, anything where the numbers begin with a capital H or SR, move on. If a telescope has 0.965 eyepieces, move on. Avoid Bird Jones type telescopes. These telescopes claim to be 6 or 8 inches in aperture, use spherical mirrors but are very short in length and use rubbish barlow lenses to increase the focal length. Just remember that aperture, not magnification reveals detail but not all apertures of equal size are not equal. Aperture is not king (as people would have you think), clear skies are and no amount of aperture will improve the view, you will always be limited to your local atmosphere.
@@1997saltydog I have been using a Celestron Astromaster 90, its f/11 and gives nice crisp views and 1.63 field of view with a 32mm plossl or 24mm 68degree eyepiece. I have the AZ version as i am not a fan of EQ mounts, i find them frustrating for panning around the sky. It also comes with the Celestron NexYZ Universal Smartphone Adapter which is expensive if bought on its own. I made some modifications but these are not required, i just love to tinker and set things up to how i want it and you can ignore the rest of my comment if you want but i am just putting it out there in the unlikely even that it helps someone. I bought and use telescope tube rings rather than the built in dovetail bar because refractors can get bottom/focuser heavy with larger eyepieces, the tube rings made it more flexible to slide it up and down the mount. There is a cheaper option and thats to just buy an extra long dovetail bar and screw on the bottom of the telescopes dovetail, i didn't think of this until after i had bought the tube rings and saw that others had took this route. Newtonion telescopes are the opposite, they can get top/focuser heavy and sometimes require a counter weight at the bottom. I changed the 1.25inch diagonal and because i am not a fan of Red Dot Finderscopes, i have a 70/400mm refractor (not the Celestron Travelscope) with a cheap 23mm 62degree Aspheric eyepiece to give a nice almost 4 degrees field of view as both a widefield telescope and a finderscope piggybacking on top of the 90mm. I have been thinking of changing it to a 30mm or 50mm right angle finderscope, as 70mm is overkill but it serves more than one purpose, its nice to both easily see a widefield of view as well as a high mag by switching between both telescopes. As i say, these are just personal preferences, even with a large dob/Newtonian telescope, the field is not that wide and to view low power, wide fields, a 60/70/80 or 90mm short tube between 400mm to 600mm focal length is needed. I don't use the NexYZ Smartphone Adapter, i use a 1.25'' Phone Clip Holder Telescope Eyepiece i bought off eBay, it clips onto the camera of your phone, slide it into the diagonal. This is the easiest and quickest way to take photos or record video through a telescope with a phone and if your phone has a Pro mode, even better. More people should know about these eyepiece phone clips. One thing that happens to most people in this hobby if you become hooked, like moving into a new home, you modify it to your own requirements.
@@allnamesaretaken I've been having a hard time picking a telescope with all the trade offs to consider with refractors and reflectors. I've been on the fence between an 8" and 10" dob, leaning towards an 10". I've also considered a mak-newtonian to mitigate the coma issue but they're more expensive and take way longer to acclimatize (1+ hour) than normal newtonians. I've probably spent a disgusting amount of time researching the right telescope for me. I'm probably overthinking it and I could just get accessories to fix whatever I don't like. Every time I remembered your comment, I was wondering why you were the only person I've encountered so far that had a negative view of them but then I looked back at your comment and you said you had a 6" one which makes sense now. Dobs I guess are supposed to be a go big or go home (and get a refractor) sort of thing. I was wondering why you didn't get the 8". The 8" is only 6 lbs heavier than the 6". 8" is supposedly the sweet spot for portability and performance. The 10" though is 12 lbs heavier than the 8" so this is where people start drawing the line in terms portability.
Just watched this but only 3 years lateOh my.What I say is better late than never.While jumping in after being gone since my late 40's it is very nice to watch some on the spot perfect advice giving destinations with the explained comments. I thank you sir for a first class presentation!!! The Fish from upstate NY USA
I built my 1st one and still use to this day, got my 1st mirror from a shadow graph then made the curved one myself, I was amazed that it worked so damn well
Thank u so much this was very helpful. I have been using a really good pair of Nikon binoculars and I’m finally ready to graduate to a telescope. The night sky is so beautiful and majestic! I saw 3 falling stars last night 🥰
Good general intro to scopes, and especially the emphasis upon STARTING WITH A GOOD PAIR OF BINOCS before throwing lots of money around. Nice job. And the commercial about the books, Tyson et al., at the end is icing on the cake.
Great work! Just one minor point. I found some of the information somewhat dated. Field Guide s & star charts have been eclipsed by apps like Star Walk & devices like Celestron s Sky Scout, or Meade's My Sky. Binoculars used to to be the standard starting point in our hobby, but the lower cost of small wide field telescope s $ eyepieces have superceded them to some degree. Everyone should have a small binocular, or monocular in any event though. As for the rest of the tutorial, right on the $. All of this meant respectfully & IMHO. Thank you for your work, really enjoyed it. Brought back great memories of my first Edmund telescope & How to use your Telescope booklet.
Personally, my favorite telescope is my oldest one: an old 114mm Tasco reflector on an eq mount. I updated it with a 1.25" focus mech and picked up a few Plossels along with an 82 degree FOV Explore Scientific eyepiece, and a really good 2X Barlow, and a 50mm finder.. I like the small scope because it's more challenging to find DSOs than my big one with a Telrad. Like fishing with ultralight gear.
I saw the cometary collision marks on jupiter with a scope like that. not much for deep sky photography but still quite usable for hundreds of objects in a decently dark sky.
I know nothing about telescopes but thinking about getting one so this was extremely helpful & very easy to understand. I don’t know why there are any thumbs down as I don’t think there should be any
@@mararoxa3152 I would generally recommend 10x50 binocs for night sky beginners. they might be a bit bulky but you can get decent ones online or at a sporting goods store for around 100 bucks and use them for day or night. for example from a chaise lounge in the dark with maybe a drink and a friend. and a phone with a sky map app
This video is excellent. All the info I need to know and none of the hype. I appreciate the direction on mention of magnification vs objective size too. An excellent resource to anyone getting started in telescope observing
The background music makes it really difficult for me to listen to. Apparently 'fashionable' to have music going on behind everything these days- but not practical and considerate to some people who have trouble with screening out background noise. Otherwise good.
My wife still doesn't understand I Can't block out background music. Looks like others who replied don't get there are people like you and I who have difficulty with it.
To beginners. The thing that helped me the most with entering astronomy is a free smartphone app called Sky Map. All of a sudden I'm figuring out what is what in the sky. All the Messier objects were a mystery until I got that app and a goto telescope. Holy cow the sky is full of cool stuff. Until I got the SKY MAP app I was just looking at planets or the moon. A little 60 mm meade etx with a 300mm focal length is fun as heck. The constellation Virgo has a cluster of messier objects worth exploring.
Very good advise! I bought a pair of binoculars... a really good pair... Swarovski 10X50 and never moved on... loved looking at the moon and galaxies and stars... they are easy to use... easy to transport.... also, I use them for bird watching.... I think most people are better served with binoculars rather a scope... especially when the mosquitos are out or it’s cold out....
10x50 is generally a good combination for viewing the sky as long as you don't need to magnify much. but for planetary you might need 10 times that. and a stable tracking mount.
1) make or become shorter by sliding overlapping sections in to each other 2) compress or condense something so that it take less space or time 3 ) an instrument using lense to magnify distant objects.
Very clear, I often have to explain just as you have...now i can just refer ti this vid, thanks for making it...also loved your book recs ...was so delighted and surprised u recommended The Doctor Who book...awesome. well done!!
Watched your video, very informative! We have used binoculars but the images we’ve tried to view in our backyard are blurry lights…. Can you suggest a telescope for us to view things in the sky that are not normally seen every night. I’m referring to suspicious objects, unidentified objects… thank you
The advice starting at minute 13 about goto not for beginners is flat out wrong. It is just so 90's. Star hopping is very frustrating and difficult to learn. The learning curve of goto or digital setting circles are far easier. A computerized telescope should be the default suggestion. A beginner considering a manual telescope should be met with the same warning as with department store telescopes. We need to modernize and rethink the advice commonly given to beginners. What will give them the least frustration? Technology is not evil. Embrace it. Also your advise on magnification is wrong. We are so used to cautioning people against the 850X 80mm refractor that we over compensate too far the other direction. The eye has a hard time seeing faint objects. In order for the eye to see a dim object it needs to be big enough to see. Most objects require high magnification to see detail or even see at all. Yes there are some large low surface brightness objects where high power diminishes the view but this is the exception not the rule. One of the best guides for use of magnification is Visual Astronomy of the Deep Sky by Roger N Clark www.amazon.com/Visual-Astronomy-Deep-Roger-Clark/dp/0521361559
Shawn Grant I disagree with your first paragraph; assuming that EVERYONE has the same degree of spatial aptitude and understanding to fully exploit the benefits of a GOTO mount straight out of the gate is probably not a good idea. SOME folks will get completely lost with one approach, and the rest might get annoyed with the other. If you don't know for sure which way is best for YOU, it's probably better to keep your costs lower or aimed at more practical investments (like MORE eyepieces to choose from) until you are CRYSTAL CLEAR about what you are actually ready to do next. And by that moment, maybe you know enough about how to find anything up there without the help of a GOTO by using the SETTING CIRCLES on your EQ mount... For some, part of the joy of exploring a new hobby is how much of the LEARNING you attain on your own. Would you tell a beginner sailor that they should get an AC50 for their first boat?
Thank you for this video. My wife asked me to research a "good" telescope as a 20th anniversary gift for me. After watching your video, I went to dig up my grandfather's 60 year old, Russian 7x35 binoculars. What an amazing perspective. I'm still convinced I want a good reflector telescope. But I will probably do research for many months still before I buy. Until then, I've got the Russian 7x35 binoculars
and 35 exit pupil is just BARELY enough light gathering for dimmer stuff (depending on your local light pollution). you will see more with 10x50's and they are not that expensive.
if your binocs are that good, consider putting them on a tripod. there are 90 degree adapters to put those on a camera tripod. normally I would recommend that for higher power binocs but maybe yours are just particularly good quality.
I got a pair of meade astro 15x70 binos. Love them. Great way to start. I do recommend a camera tripod or other mount, but even freehand, they're great.
@@nathannugent6038 yes. Cab distinguish pinpoint lights and some colors. Antares is a gold, Betelguese is reddish, etc. Planets are discs, or points as is Saturn. Binos are goid for large formations like clusters and closer galaxies like Andromeda's.
Great video, this is exactly the reason I’m sticking with my Orion 20 x 80 binoculars for now... so much to digest and consider before making the big purchase...or medium purchase. 😁
@@mikehoncho2640 , yes eventually...even with the supply chain issues. I ended up with an Orion 5” Mak-Cass on a Go To Mount. Not exactly a “light bucket” by some standards but it’s proving to be pretty good for planetary & star clusters. I have yet to go after any Messier / DSO’s. The time spent with the binoculars was very helpful and they’re still a great “grab N go”.
Is it not misleading to use images taken from something like Hubble when explaining you can see a lot with cheap binoculars? Bearing in mind this is aimed at people to whom the mismatch wouldn't be immediately obvious?
It is simple for beginners. Below 4 inches of aperture: buy a refractor. Above 4 inches buy a reflector. Never ever buy a reflector below 4 inches of aperture. The entry ticket to space is for just above 100 USD for a cheap 70 mm F10 refractor with Kelner eyepieces. Binoculars as main instrument are not worth it unless you have access to dark skies.
binocs are still good if you are looking at something large or bright. aside of that I agree, and do not even know if anyone sells a reflector under 4 inches aperture anyhow.
@@JG27Korny they will "shine" better on a tripod or at least steadied against some stable surface. That was my point. I also have zoom binocs and they have the same characteristics.
1: Buy a good pair of binoculars (just don't plan on getting the views he was showing while he was talking about them). Having said that, I still love using mine on the night sky.
good binocs will make most objects discernible but not BIG. Published images tend to exaggerate that, since post-edit crops can effectively digital-zoom.
not necessarily a bad deal if the tube assembly and optics are good quality and the tripod-mount assembly is serious and not cheap crap. The BIG difference is what eyepieces you use with it (the ones that come with, are usually kellners and you can do better that that) and it does not hurt to have a good finder, even a tracking motor if it didn't come with one.
@@kaijinc3639 seriously, don't date someone just to get a telescope. And no, it is not the FASTEST WAY either. I once expressed interest in a young lady, who seemed rather un-interested in me, but did say that if I had an airplane, I should call her. It was the FASTEST way for me to decide not to.
Thanks for this video. I have been thinking about getting a telescope for a while but didn’t’t know the basics. I live in in the Southern Hemisphere (Bali where once every year they celebrate Nyepi. All lights turned off on a moonless night and the sky is amazing.) and was wondering about transporting a telescope on a plane if I go home (UK) or any other country. Baggage handlers can be a bit rough.
The only advice offered here I would counter is the idea that a GoTo Mount is not for beginners. In my estimation, a beginner trying to find a nebula or other normally invisible object in the night sky with a dobsonian or manual reflector is an exercise in frustration that is the very reason why most telescopes end up being clothes racks. In today’s smartphone world... a phone app like Pocket Universe that can tell you what start you are pointing it at, and a GoTo Mount that you can pretty easily align to two of 3 major stars to get the thing oriented is the minimum amount of technological competence I would expect out of any pre-teen. And for my money, the Alt Az GoTo mounts that are common in the affordable range of 4” to 6” Cassegrain and Maks make any night spent stargazing a much greater pleasure. It’s the Dobs and non-computerized mounts that are better suited to the experienced astronomer who knows the night sky well.
christopher is right, GO-TO mounts are not quite as "automatic" as the ads and marketing suggest. All such gear has a learning curve including the scopes and mounts without any computers at all.
When I was a child my parents indulged my interest in astronomy with a 2.4 inch refractor telescope with an equitorial mount and every conceivable accessory in its day, the mid 1950s. I did a lot of star gazing with it. More recently I considered a much more ambitious telescope. I decided looking up at the sky was not what I wanted to do, I wanted to see what was there. So using my computer I can see anything I want to with the best telescopes in the world. I'm a happy camper. BTW when I see images from space telescopes I'm seeing the same thing astronomers see.
that approach also allows you to look at the sky with a big hi-res computer monitor, while sitting in a fairly comfy chair, in a warm room with a hot toddy or chai tea. Star-hopping out in the dark was more fun before my hair was this gray.
@@tracyavent-costanza346 Do I want to play with a telescope or do I want to see what the best telescopes in the world have already found and learn what it means from astronomers who are experts in their field? They've already accumulated a lifetime of images I'd never see with any telescope I could buy. So do I want to play with another toy or do I want to learn what that toy could never teach me?
@@markfischer3626 yep there's that...google sky can show you stuff that you would never see with an earthbound scope too, such as sat imaging of the surface of most planets (or cloud layers of the gas giants) as well as quite a few of their larger moons. and lately some of the imaging from the plutonian system too. Good luck getting THAT from a ground based scope.
@@tracyavent-costanza346 Google earth can give you a tour of the surface of Mars. When I was young the most powerful telescope in the world, the 200 inch Hale reflector on Mount Palomar couldn't do that. I can see details of galaxies billions of light years away and get an explanation from people who have devoted their lives to studying them as a narrative while I'm looking at it. It was remarkable that Hubbell could discover V1 in the Andromeda galaxy. back in the 1920s. Can you buy a telescope that could do that?.
@@markfischer3626 I just posted another comment, to another item on this thread to that effect. google sky can give you sat imaging on pretty much all of the planets and a lot of their moons. no way would you be able to see that from an earth bound scope, and I don't care how much you spent on it.
Eileen Level, I use two different pair of binos Celestron 15x70 Skymaster and 10x50 Tasco. The Celestron are heavy and hard to hold steady by hand, I use a walking staff as a mount. The Tasco are much easier to use and less expensive. My advice get something basic and go outside and look up, enjoy learning the night sky and names of the constellation of different cultures. Take care. Be safe.
@@cannonball5515 agreed. for anything about 10x you pretty much need a tripod. for the 10x binocs, a chaise lounge and a sweater suffices for a tripod. a cocktail drink is optional.
If you had to pick between 2 telescope one being StarSense Explorer DX 102AZ refractor and the other StarSense Explorer DX 130AZ reflector wich one would you pick, I have been month still cant decide please help me out
Hello I'm weighing up buying the Celestron 100AZ vs a Meade ETX80 - can anyone advise which is better? I can get for roughly the same price. The Meade is older I know but has the automatic robotic object finder. Is the Meade the better option? Thanks for any help! Alice
It's good that Darrell covered the 3 basic types of scopes. However, this vid is certainly not a buyers guide (stated in title) by any far stretch of the imagination as no specific makes and models are even mentioned.
rccrashburn true no brands are mentioned however brands and styles change over time but the general principles in this video will probable not change as quickly I would think :)
if you are considerd a NEW scope rig, expect to spend 300USD for anything decent. for USED (from a reputable seller) you might get something decent for half that. but both would be beginner equipment, probably not for photographic imaging
Very informative video. Do you have a preference between deflector, refractor or cassegrain for viewing and astrophotography. I have been reading and watching many youtube videos. Some say that there can be focal point problems with some scopes if you're trying to do astrophotography and use the same scope for viewing. I heard that the cassegrain might be the best selection for this but was wondering what your opinion would be. Thank you.
that generally is my experience; for visual work, binocs or a decent newtonian reflector or maybe a dobsonian if you don't want to do any photography. if you DO want to do photography, then a cassegrain or a refractor.
Hello, Tom. Man, there are so many to choose from. Here are a few that I like: National Geographic Backyard Guide to the Night Sky by Andrew Fazekas, Stars and Planets by Ian Ridpath, and Peterson Field Guide to Stars and Planets by Jay Pasachoff . Additionally, I highly recommend NightWatch, by Terence Dickinson and Turn Left at Orion by Guy Consolmagno
@Jim Man higher focal length is more zoom. higher f number is smaller aperture and therefore less light. i would recommend the orion model i mentioned over the explore scientific. beginners will find the equatorial mount difficult to use. get an alt-azimuth mount, it's more intuitive for beginners. you can add custom eyepieces later to increase zoom if you want. also the bundled finderscopes with most telescopes are cheap junk. i recommend this finderscope - smile.amazon.com/gp/product/B00009X3UU/
not if you really wana see much with it, no. you will need a good strong mount with counterweights, a strong base to go with it. if you want to go a chepaer route, you might be able to fine a 10 inch dob with no tracking on the used market. a full blown 10 inch newtonian (OTA) will weigh in at about 70 pounds and pretty much destroy a cheap mount.
8 inch or larger apperture for deep sky objects. the big detail after that, is how your mount works, then exposure tracking, stacking and all kinds of details about your camera and post-processing techniques for your image. in short, sign up for some astro-photog blogs.
depends on what you want know and what you already know. phone-based digital sky maps are pretty popular, despite small screen sizes. they can shown you a lot. there are plenty of different opinions about those, so I'd advise reading some of the reviews- both positive and otherwise.
that is more about whether you have a lot of light pollution or are trying to do astrophotography of dim objects with a newtonian reflector. Generally your fancy photographic rigs are refractors or cassegrains. no matter how fancy your scope, if your sky is light polluted, your photos will come out kind of Green.
Good vid but, haven't they forgotten to mention the max usable magnification of each scope. It's a simple to work out. Aperture x 2. Example 100mm aperture x 2 = Maximum usable mag = x200.
Hi,I want to purchase a 10 inch dobsonian reflector telescope. So I just wanted you advice whether I will get a good experience with 10inch reflector or I should go for cheaper option or smaller one ?
depends on what you want to see and how dark your sky is. for deep sky objects, 10 inches might be necessary but light pollution could still prevent you from seeing them without camera work.
He gets some details wrong. The difference between a Schmidt-Cassegrainian and Classical Cassegrainian is not mentioned. A Schmidt-Cassegrainian is not noticeably dimmer than a refractor or reflector of similar size. The fork mount shown is equatorially mounted, not alt-az. There are other videos out in UA-cam land that are more accurate. View a few others before you buy.
these days there aren't that many classical cassegrains on the 'new' market. the color corrector keeps the optics clean and provides a convenient mount for the secondary. otherwise you have a mirror spider and have to fiddle with alignment like a newtonian, and also plan to spent time cleaning mirrors.
The best introductory video to telescopes I've ever seen. Not a single filler or wasted word.
Yawn* . .Is history class over yet?
I agree! Tight but comprehensive enough. And he's very engaging, too!
Excellent overview of telescopes and the strengths and weakness of each (refractor, reflector, catadioptric). This is a video I would recommend to those thinking of getting a telescope for observing the night sky.
Absolutely fantastic presentation. I'm enthralled as well as having learnt not just the how it works but why it works that way. Great upload . Thank you.
With respect to refractors (i own both refractors and Newtonians), anything above an F/8 ratio should have little to no chromatic aberration whatever magnification you use.
Coatings have improved a lot over the years where they can reduce it considerably on faster F/ratios. There are also filters that can help with it but if you are cheap, just use a Yellow filter. And here's one that's rarely mentioned, not everyone sees it, even on planets like Jupiter.
As for Newtonians, you will see diffraction spikes created by the spider legs on bright objects and short F/ratio Newtonians can overwhelm images in astrophotography. They also need a parabolic mirror (which increases the price) unless its an F/8 or more, though the F/ratio varies depending on the aperture size.
I owned a 6inch dob but got rid of it because it never showed me anything my 90mm refractor showed me. The 90mm is easily portable, whereas the dob was heavy, very heavy. There were many nights where the refractor had a cleaner image than the dob, despite being climatized and collimated. Refractors handle the atmosphere better than Newtonians.
It doesn't matter how good coatings are, even ignoring the central obstruction on a Newtonian, glass transmits more light than mirrors ever could and refractors being a closed system benefits it even more, no tube currents, nothing to effect the light path right up to the eyepiece.
I am of the opinion that if you buy anything less than an 8inch dob, then it should be a refractor and i never recommend dobs to new astronomers because i have seen too many sent back because of their size.
A 60mm or more refractor (Yes, a 60mm, they can show a surprising amount of stuff in the night sky like the full Messier catalogue, Jupiter and Saturn's rings and the moon) but a 70mm or more is better but refractors can get heavy after 102mm aperture, or at least the tripods can.
Couple of pointers:
Plastic lenses aren't always that bad, 62degree Aspheric's are hard to beat for the price.
If a telescope comes with an eyepiece like H20mm, SR4mm, anything where the numbers begin with a capital H or SR, move on.
If a telescope has 0.965 eyepieces, move on.
Avoid Bird Jones type telescopes. These telescopes claim to be 6 or 8 inches in aperture, use spherical mirrors but are very short in length and use rubbish barlow lenses to increase the focal length.
Just remember that aperture, not magnification reveals detail but not all apertures of equal size are not equal. Aperture is not king (as people would have you think), clear skies are and no amount of aperture will improve the view, you will always be limited to your local atmosphere.
Excellent review, many thanks!
You saved me from buying a bird-jones model
They aren't that bad but you're right the refractor is better
What 90mm refractor do you have? Asking for a friend...
@@1997saltydog I have been using a Celestron Astromaster 90, its f/11 and gives nice crisp views and 1.63 field of view with a 32mm plossl or 24mm 68degree eyepiece. I have the AZ version as i am not a fan of EQ mounts, i find them frustrating for panning around the sky. It also comes with the Celestron NexYZ Universal Smartphone Adapter which is expensive if bought on its own.
I made some modifications but these are not required, i just love to tinker and set things up to how i want it and you can ignore the rest of my comment if you want but i am just putting it out there in the unlikely even that it helps someone.
I bought and use telescope tube rings rather than the built in dovetail bar because refractors can get bottom/focuser heavy with larger eyepieces, the tube rings made it more flexible to slide it up and down the mount. There is a cheaper option and thats to just buy an extra long dovetail bar and screw on the bottom of the telescopes dovetail, i didn't think of this until after i had bought the tube rings and saw that others had took this route. Newtonion telescopes are the opposite, they can get top/focuser heavy and sometimes require a counter weight at the bottom.
I changed the 1.25inch diagonal and because i am not a fan of Red Dot Finderscopes, i have a 70/400mm refractor (not the Celestron Travelscope) with a cheap 23mm 62degree Aspheric eyepiece to give a nice almost 4 degrees field of view as both a widefield telescope and a finderscope piggybacking on top of the 90mm. I have been thinking of changing it to a 30mm or 50mm right angle finderscope, as 70mm is overkill but it serves more than one purpose, its nice to both easily see a widefield of view as well as a high mag by switching between both telescopes.
As i say, these are just personal preferences, even with a large dob/Newtonian telescope, the field is not that wide and to view low power, wide fields, a 60/70/80 or 90mm short tube between 400mm to 600mm focal length is needed.
I don't use the NexYZ Smartphone Adapter, i use a 1.25'' Phone Clip Holder Telescope Eyepiece i bought off eBay, it clips onto the camera of your phone, slide it into the diagonal. This is the easiest and quickest way to take photos or record video through a telescope with a phone and if your phone has a Pro mode, even better. More people should know about these eyepiece phone clips.
One thing that happens to most people in this hobby if you become hooked, like moving into a new home, you modify it to your own requirements.
@@allnamesaretaken I've been having a hard time picking a telescope with all the trade offs to consider with refractors and reflectors. I've been on the fence between an 8" and 10" dob, leaning towards an 10". I've also considered a mak-newtonian to mitigate the coma issue but they're more expensive and take way longer to acclimatize (1+ hour) than normal newtonians. I've probably spent a disgusting amount of time researching the right telescope for me. I'm probably overthinking it and I could just get accessories to fix whatever I don't like.
Every time I remembered your comment, I was wondering why you were the only person I've encountered so far that had a negative view of them but then I looked back at your comment and you said you had a 6" one which makes sense now. Dobs I guess are supposed to be a go big or go home (and get a refractor) sort of thing. I was wondering why you didn't get the 8". The 8" is only 6 lbs heavier than the 6". 8" is supposedly the sweet spot for portability and performance. The 10" though is 12 lbs heavier than the 8" so this is where people start drawing the line in terms portability.
One of the most informative videos I have ever found on UA-cam. Thank you ! !
The best astronomy Chanel. Thank you.
the very best introduction I ever watched! Well categorised and explained. Thank you!
Just watched this but only 3 years lateOh my.What I say is better late than never.While jumping in after being gone since my late 40's it is very nice to watch some on the spot perfect advice giving destinations with the explained comments.
I thank you sir for a first class presentation!!!
The Fish from upstate NY USA
What a fantastic details about telescope.i just stuck to this video from beginning ,I like the way you’re detailing telescope
I built my 1st one and still use to this day, got my 1st mirror from a shadow graph then made the curved one myself, I was amazed that it worked so damn well
Well done! That's a scope you really appreciate all the more, having built it yourself.
Very informative and effective for people trying to step into astronomy and astrophotography
Thank u so much this was very helpful. I have been using a really good pair of Nikon binoculars and I’m finally ready to graduate to a telescope. The night sky is so beautiful and majestic! I saw 3 falling stars last night 🥰
This is very good advice. Well presented. Knowledgable. Clear and concise.
What a great video. Very informative and easily explained.Thank you for everything.
Holy snap.... I learned a lot!
Thank you for the lesson, now I feel a little more informed on what I should get.
Of which nationality you are
Thank you. Back in the early 80’s I attended a few star parties just outside of LR.
At Pinnacle Mountain?
Glad he said binoculars. That is my start and endgame.
Different goals different tools.
Good general intro to scopes, and especially the emphasis upon STARTING WITH A GOOD PAIR OF BINOCS before throwing lots of money around.
Nice job. And the commercial about the books, Tyson et al., at the end is icing on the cake.
Great work! Just one minor point. I found some of the information somewhat dated. Field Guide s & star charts have been eclipsed by apps like Star Walk & devices like Celestron s Sky Scout, or Meade's My Sky. Binoculars used to to be the standard starting point in our hobby, but the lower cost of small wide field telescope s $ eyepieces have superceded them to some degree. Everyone should have a small binocular, or monocular in any event though. As for the rest of the tutorial, right on the $. All of this meant respectfully & IMHO. Thank you for your work, really enjoyed it. Brought back great memories of my first Edmund telescope & How to use your Telescope booklet.
Personally, my favorite telescope is my oldest one: an old 114mm Tasco reflector on an eq mount. I updated it with a 1.25" focus mech and picked up a few Plossels along with an 82 degree FOV Explore Scientific eyepiece, and a really good 2X Barlow, and a 50mm finder.. I like the small scope because it's more challenging to find DSOs than my big one with a Telrad. Like fishing with ultralight gear.
I saw the cometary collision marks on jupiter with a scope like that. not much for deep sky photography but still quite usable for hundreds of objects in a decently dark sky.
GOOD one! There are similar videos, but this one brings it all to a point! Well done!
This is the only video I need to get started - the best by far. Thanks so much.
I know nothing about telescopes but thinking about getting one so this was extremely helpful & very easy to understand. I don’t know why there are any thumbs down as I don’t think there should be any
have you already used binocs to look at the sky? if so what was your experience with that?
No, I’ve not but that’s a really good idea to start off with ~ thanku.
@@mararoxa3152
I would generally recommend 10x50 binocs for night sky beginners. they might be a bit bulky but you can get decent ones online or at a sporting goods store for around 100 bucks and use them for day or night. for example from a chaise lounge in the dark with maybe a drink and a friend. and a phone with a sky map app
This video is excellent. All the info I need to know and none of the hype. I appreciate the direction on mention of magnification vs objective size too. An excellent resource to anyone getting started in telescope observing
Brilliant presentation. I am going to watch it again and again.
Very informative video, thanks so much! I did notes just as at the university, this is precious knowledge for all your life.
The background music makes it really difficult for me to listen to. Apparently 'fashionable' to have music going on behind everything these days- but not practical and considerate to some people who have trouble with screening out background noise. Otherwise good.
I advice a hearing aid first.
My wife still doesn't understand I Can't block out background music. Looks like others who replied don't get there are people like you and I who have difficulty with it.
Surprisingly easy to understand for an absolute beginner like me, excellent presentacion Sir, thank you.
To beginners.
The thing that helped me the most with entering astronomy is a free smartphone app called Sky Map. All of a sudden I'm figuring out what is what in the sky. All the Messier objects were a mystery until I got that app and a goto telescope. Holy cow the sky is full of cool stuff. Until I got the SKY MAP app I was just looking at planets or the moon.
A little 60 mm meade etx with a 300mm focal length is fun as heck.
The constellation Virgo has a cluster of messier objects worth exploring.
to see deep sky requires dark sky. no street lights.
Great overview. Thanks for including price ideas 😎
Wow thank you so much for this guidance on scopes....you absolutely expanded my aperture towards these devices. 😇
Very good advise! I bought a pair of binoculars... a really good pair... Swarovski 10X50 and never moved on... loved looking at the moon and galaxies and stars... they are easy to use... easy to transport.... also, I use them for bird watching.... I think most people are better served with binoculars rather a scope... especially when the mosquitos are out or it’s cold out....
For $3500? That was not really his point for the beginner.
10x50 is generally a good combination for viewing the sky as long as you don't need to magnify much. but for planetary you might need 10 times that. and a stable tracking mount.
Thank you for the knowledge 💞
I will start use binoculars 💞
1) make or become shorter by sliding overlapping sections in to each other
2) compress or condense something so that it take less space or time
3 ) an instrument using lense to magnify distant objects.
Definitely it helps .. such a wonderful explanation and thanks for this knowledge
Very clear, I often have to explain just as you have...now i can just refer ti this vid, thanks for making it...also loved your book recs ...was so delighted and surprised u recommended The Doctor Who book...awesome. well done!!
Thank you for this very useful video! Made it easy to understand for an amateur!
Watched your video, very informative! We have used binoculars but the images we’ve tried to view in our backyard are blurry lights…. Can you suggest a telescope for us to view things in the sky that are not normally seen every night. I’m referring to suspicious objects, unidentified objects… thank you
Such a great and helpful video !! thanks for sharing
The advice starting at minute 13 about goto not for beginners is flat out wrong. It is just so 90's. Star hopping is very frustrating and difficult to learn. The learning curve of goto or digital setting circles are far easier. A computerized telescope should be the default suggestion. A beginner considering a manual telescope should be met with the same warning as with department store telescopes. We need to modernize and rethink the advice commonly given to beginners. What will give them the least frustration? Technology is not evil. Embrace it.
Also your advise on magnification is wrong. We are so used to cautioning people against the 850X 80mm refractor that we over compensate too far the other direction. The eye has a hard time seeing faint objects. In order for the eye to see a dim object it needs to be big enough to see. Most objects require high magnification to see detail or even see at all. Yes there are some large low surface brightness objects where high power diminishes the view but this is the exception not the rule. One of the best guides for use of magnification is Visual Astronomy of the Deep Sky by Roger N Clark www.amazon.com/Visual-Astronomy-Deep-Roger-Clark/dp/0521361559
Goto mounts are really expensive and put off most people
Shawn Grant I disagree with your first paragraph; assuming that EVERYONE has the same degree of spatial aptitude and understanding to fully exploit the benefits of a GOTO mount straight out of the gate is probably not a good idea. SOME folks will get completely lost with one approach, and the rest might get annoyed with the other. If you don't know for sure which way is best for YOU, it's probably better to keep your costs lower or aimed at more practical investments (like MORE eyepieces to choose from) until you are CRYSTAL CLEAR about what you are actually ready to do next. And by that moment, maybe you know enough about how to find anything up there without the help of a GOTO by using the SETTING CIRCLES on your EQ mount... For some, part of the joy of exploring a new hobby is how much of the LEARNING you attain on your own. Would you tell a beginner sailor that they should get an AC50 for their first boat?
What a great guy - thank you for this informational video.
Thank you for this video.
My wife asked me to research a "good" telescope as a 20th anniversary gift for me. After watching your video, I went to dig up my grandfather's 60 year old, Russian 7x35 binoculars. What an amazing perspective.
I'm still convinced I want a good reflector telescope. But I will probably do research for many months still before I buy.
Until then, I've got the Russian 7x35 binoculars
Good call.
and 35 exit pupil is just BARELY enough light gathering for dimmer stuff (depending on your local light pollution). you will see more with 10x50's and they are not that expensive.
Tracy Avent-Costanza 35mm is diameter, not exit pupil.
if your binocs are that good, consider putting them on a tripod. there are 90 degree adapters to put those on a camera tripod. normally I would recommend that for higher power binocs but maybe yours are just particularly good quality.
@@Megawatt
diameter of the objective lenses. effectively exit pupil. the bigger the brighter the image, all other things equal.
I got a pair of meade astro 15x70 binos. Love them. Great way to start. I do recommend a camera tripod or other mount, but even freehand, they're great.
Can You See the stars etc quite clear if u don't mind me asking
@@nathannugent6038 yes. Cab distinguish pinpoint lights and some colors. Antares is a gold, Betelguese is reddish, etc. Planets are discs, or points as is Saturn.
Binos are goid for large formations like clusters and closer galaxies like Andromeda's.
yep, anythying above about 10x you need a tripod. and 70 will given you fairly bright images.
What a great video. Very informative and easily explained. Thank you.
very cool video. i really got inspired to look after the books to order them.
That was an extremely helpful and focused presentation. Many thanks. T
This was actually extremely helpful!!!!!!
Great video, this is exactly the reason I’m sticking with my Orion 20 x 80 binoculars for now... so much to digest and consider before making the big purchase...or medium purchase. 😁
did u buy something ?
@@mikehoncho2640 , yes eventually...even with the supply chain issues. I ended up with an Orion 5” Mak-Cass on a Go To Mount. Not exactly a “light bucket” by some standards but it’s proving to be pretty good for planetary & star clusters. I have yet to go after any Messier / DSO’s. The time spent with the binoculars was very helpful and they’re still a great “grab N go”.
Is it not misleading to use images taken from something like Hubble when explaining you can see a lot with cheap binoculars? Bearing in mind this is aimed at people to whom the mismatch wouldn't be immediately obvious?
8:06 should say "disadvantage" and not "advantage".... great vid BTW - thanks
Excellent information presented well!
Thanks
Everything terrynak said. Excellent. Thank you so much!
Thank you for a very informative and Superb video.
Wow it's cool to see Liam Neeson explaining telescopes!!
Laking613
😐 you DEFINETELY need to use telescopes as spectacles lol
Came here out of curiosity and now I love this channel!
Really useful and informative video, thank you for sharing !
It is simple for beginners. Below 4 inches of aperture: buy a refractor. Above 4 inches buy a reflector. Never ever buy a reflector below 4 inches of aperture.
The entry ticket to space is for just above 100 USD for a cheap 70 mm F10 refractor with Kelner eyepieces. Binoculars as main instrument are not worth it unless you have access to dark skies.
binocs are still good if you are looking at something large or bright.
aside of that I agree, and do not even know if anyone sells a reflector under 4 inches aperture anyhow.
@@tracyavent-costanza346 I have 20x80 binoculars, and they are worth it, but they really start to shine under darker skies.
@@JG27Korny
they will "shine" better on a tripod or at least steadied against some stable surface. That was my point. I also have zoom binocs and they have the same characteristics.
@@tracyavent-costanza346 A tripod adds one magnitude for binoculars.
@@JG27Korny
one magnitude of what?
Excellent presentation!
Very nice and compact guide
1: Buy a good pair of binoculars (just don't plan on getting the views he was showing while he was talking about them). Having said that, I still love using mine on the night sky.
I enjoyed the picture of the nebula through the binoculars 😄
good binocs will make most objects discernible but not BIG. Published images tend to exaggerate that, since post-edit crops can effectively digital-zoom.
I paid $300 for a 114mm (4.5 inches) reflector, that's sad lol. I guess Argentina sucks at everything when related to pricing...
That's typical
not necessarily a bad deal if the tube assembly and optics are good quality and the tripod-mount assembly is serious and not cheap crap. The BIG difference is what eyepieces
you use with it (the ones that come with, are usually kellners and you can do better that that) and it does not hurt to have a good finder, even a tracking motor if it didn't come with one.
Dear sister, the fastest way to get a good telescope is to get an astronomer boyfriend...
@@kaijinc3639
seriously, don't date someone just to get a telescope. And no, it is not the FASTEST WAY either.
I once expressed interest in a young lady, who seemed rather un-interested in me, but did say that if I had an airplane, I should call her.
It was the FASTEST way for me to decide not to.
@@tracyavent-costanza346 I have several airplanes.
what you show as Schmidt-Cassegrain telescope @9:10 is actually Maksutov
Helpful. Thank you for posting.
is takahashi a good brand to start with
Thank you so much for the amazing video!
Thanks for this video. I have been thinking about getting a telescope for a while but didn’t’t know the basics. I live in in the Southern Hemisphere (Bali where once every year they celebrate Nyepi. All lights turned off on a moonless night and the sky is amazing.) and was wondering about transporting a telescope on a plane if I go home (UK) or any other country. Baggage handlers can be a bit rough.
if a newtonian or cass you may have to re-collimate once you get it out of airline baggage.
pack it in a case with foam.
My barlow lenses only make my image blurry, what should i do?
what kind of binoculars should I start with? don't want to spend more than $70
The only advice offered here I would counter is the idea that a GoTo Mount is not for beginners. In my estimation, a beginner trying to find a nebula or other normally invisible object in the night sky with a dobsonian or manual reflector is an exercise in frustration that is the very reason why most telescopes end up being clothes racks.
In today’s smartphone world... a phone app like Pocket Universe that can tell you what start you are pointing it at, and a GoTo Mount that you can pretty easily align to two of 3 major stars to get the thing oriented is the minimum amount of technological competence I would expect out of any pre-teen.
And for my money, the Alt Az GoTo mounts that are common in the affordable range of 4” to 6” Cassegrain and Maks make any night spent stargazing a much greater pleasure. It’s the Dobs and non-computerized mounts that are better suited to the experienced astronomer who knows the night sky well.
christopher is right, GO-TO mounts are not quite as "automatic" as the ads and marketing suggest. All such gear has a learning curve including the scopes and mounts without any computers at all.
Hi need some advice on a good telescope any ideas are a help
When I was a child my parents indulged my interest in astronomy with a 2.4 inch refractor telescope with an equitorial mount and every conceivable accessory in its day, the mid 1950s. I did a lot of star gazing with it. More recently I considered a much more ambitious telescope. I decided looking up at the sky was not what I wanted to do, I wanted to see what was there. So using my computer I can see anything I want to with the best telescopes in the world. I'm a happy camper. BTW when I see images from space telescopes I'm seeing the same thing astronomers see.
that approach also allows you to look at the sky with a big hi-res computer monitor, while sitting in a fairly comfy chair, in a warm room with a hot toddy or chai tea. Star-hopping out in the dark was more fun before my hair was this gray.
@@tracyavent-costanza346 Do I want to play with a telescope or do I want to see what the best telescopes in the world have already found and learn what it means from astronomers who are experts in their field? They've already accumulated a lifetime of images I'd never see with any telescope I could buy. So do I want to play with another toy or do I want to learn what that toy could never teach me?
@@markfischer3626 yep there's that...google sky can show you stuff that you would never see with an earthbound scope too, such as sat imaging of the surface of most planets (or cloud layers of the gas giants) as well as quite a few of their larger moons. and lately some of the imaging from the plutonian system too. Good luck getting THAT from a ground based scope.
@@tracyavent-costanza346 Google earth can give you a tour of the surface of Mars. When I was young the most powerful telescope in the world, the 200 inch Hale reflector on Mount Palomar couldn't do that. I can see details of galaxies billions of light years away and get an explanation from people who have devoted their lives to studying them as a narrative while I'm looking at it. It was remarkable that Hubbell could discover V1 in the Andromeda galaxy. back in the 1920s. Can you buy a telescope that could do that?.
@@markfischer3626 I just posted another comment, to another item on this thread to that effect. google sky can give you sat imaging on pretty much all of the planets and a lot of their moons. no way would you be able to see that from an earth bound scope, and I don't care how much you spent on it.
Can you recommend quality binoculars that will allow me to view what you mentioned at the top of your video, please.
Eileen Level, I use two different pair of binos Celestron 15x70 Skymaster and 10x50 Tasco. The Celestron are heavy and hard to hold steady by hand, I use a walking staff as a mount. The Tasco are much easier to use and less expensive. My advice get something basic and go outside and look up, enjoy learning the night sky and names of the constellation of different cultures. Take care. Be safe.
@@cannonball5515
agreed. for anything about 10x you pretty much need a tripod.
for the 10x binocs, a chaise lounge and a sweater suffices for a tripod. a cocktail drink is optional.
Great video. What would be the best scope for somebody interested in variable star observing?
if you want to see variable stars, you are best to do photography, and compare images over weeks, months or years.
If you had to pick between 2 telescope one being StarSense Explorer DX 102AZ refractor and the other StarSense Explorer DX 130AZ reflector wich one would you pick, I have been month still cant decide please help me out
excellent guide of telescopes!!!
Hello I'm weighing up buying the Celestron 100AZ vs a Meade ETX80 - can anyone advise which is better? I can get for roughly the same price. The Meade is older I know but has the automatic robotic object finder. Is the Meade the better option? Thanks for any help! Alice
It's good that Darrell covered the 3 basic types of scopes. However, this vid is certainly not a buyers guide (stated in title) by any far stretch of the imagination as no specific makes and models are even mentioned.
rccrashburn true no brands are mentioned however brands and styles change over time but the general principles in this video will probable not change as quickly I would think :)
the orion website will give you plenty of particulars, models, prices, options, accessories and so forth.
Sir which telescope should I buy as I'm beginner. Please guide about money to spend also.
if you are considerd a NEW scope rig, expect to spend 300USD for anything decent.
for USED (from a reputable seller) you might get something decent for half that.
but both would be beginner equipment, probably not for photographic imaging
How Are telescope Bresser DOB 203?
HELL YEAH! Super Informative!
An excellent video. Thank you.
Very informative video. Do you have a preference between deflector, refractor or cassegrain for viewing and astrophotography. I have been reading and watching many youtube videos. Some say that there can be focal point problems with some scopes if you're trying to do astrophotography and use the same scope for viewing. I heard that the cassegrain might be the best selection for this but was wondering what your opinion would be. Thank you.
that generally is my experience; for visual work, binocs or a decent newtonian reflector or maybe a dobsonian if you don't want to do any photography. if you DO want to do photography,
then a cassegrain or a refractor.
Great video. Thank you for making it.
What about a suggestion on a good field guide?
Hello, Tom. Man, there are so many to choose from. Here are a few that I like: National Geographic Backyard Guide to the Night Sky by Andrew Fazekas, Stars and Planets by Ian Ridpath, and Peterson Field Guide to Stars and Planets by Jay Pasachoff . Additionally, I highly recommend NightWatch, by Terence Dickinson and Turn Left at Orion by Guy Consolmagno
@@darrellheath9776 Thank you. Much appreciated recommendations.
I've been using a fairly powerful rifle scope...I'm ready for a telescope 🔭 now
Very informative video, thanks. What's the name of the soundtrack?
I'm a fan of maksutovs. Very compact and sturdy design. They are also inexpensive, like the Orion 9825.
@Jim Man higher focal length is more zoom. higher f number is smaller aperture and therefore less light. i would recommend the orion model i mentioned over the explore scientific. beginners will find the equatorial mount difficult to use. get an alt-azimuth mount, it's more intuitive for beginners. you can add custom eyepieces later to increase zoom if you want. also the bundled finderscopes with most telescopes are cheap junk. i recommend this finderscope - smile.amazon.com/gp/product/B00009X3UU/
@@TMS5100
no matter what kind of mount, I have to agree that a good finder (optical or tel-rad style) is a worth-while add on.
can i use 10 inch newtonian telescope with simple mount wihout expensive motor drives ?
not if you really wana see much with it, no.
you will need a good strong mount with counterweights, a strong base to go with it.
if you want to go a chepaer route, you might be able to fine a 10 inch dob with no tracking on the used market.
a full blown 10 inch newtonian (OTA)
will weigh in at about 70 pounds and pretty much destroy a cheap mount.
Excellent video. Thank you !
So good video sir thanks with love
Sir , please tell me in dobsonia telescope is good for galaxy photography
8 inch or larger apperture for deep sky objects. the big detail after that, is how your mount works, then exposure tracking, stacking and all kinds of details about your camera and post-processing techniques for your image.
in short, sign up for some astro-photog blogs.
may sound a stupid question but what field guide do you recommend?
depends on what you want know and what you already know. phone-based digital sky maps are pretty popular, despite small screen sizes. they can shown you a lot. there are plenty of different opinions about those, so I'd advise reading some of the reviews- both positive and otherwise.
very useful advice. many thanks.
I was told that a reflector with a mirror over four and one half inches collects too much ambient light, so you should stay below that?
that is more about whether you have a lot of light pollution or are trying to do astrophotography of dim objects with a newtonian reflector. Generally your fancy photographic rigs are refractors or cassegrains. no matter how fancy your scope, if your sky is light polluted, your photos will come out kind of Green.
Good vid but, haven't they forgotten to mention the max usable magnification of each scope. It's a simple to work out. Aperture x 2. Example 100mm aperture x 2 = Maximum usable mag = x200.
Hi,I want to purchase a 10 inch dobsonian reflector telescope.
So I just wanted you advice whether I will get a good experience with 10inch reflector or I should go for cheaper option or smaller one ?
depends on what you want to see and how dark your sky is. for deep sky objects, 10 inches might be necessary but light pollution could still prevent you from seeing them without camera work.
He gets some details wrong. The difference between a Schmidt-Cassegrainian and Classical Cassegrainian is not mentioned. A Schmidt-Cassegrainian is not noticeably dimmer than a refractor or reflector of similar size. The fork mount shown is equatorially mounted, not alt-az. There are other videos out in UA-cam land that are more accurate. View a few others before you buy.
these days there aren't that many classical cassegrains on the 'new' market. the color corrector keeps the optics clean and provides a convenient mount for the secondary. otherwise you have a mirror spider and have to fiddle with alignment like a newtonian, and also plan to spent time cleaning mirrors.
Enjoyed the ....lesson.....thank you....
Astounding explanation.
In fact I DO step outside at night, look up at the sky and wonder "where'd all the stars go?". I'm left in a state of awelessness.