@@TheSighphiguy That's why 100 degree eyepieces exist, you can see the full moon at 200X with an APM 100 degree or 110 degree eyepiece depending on the telescope. The drift time on planets is insane.
Baffle Tube Diameter is another factor to consider when selecting EPs for Catadioptric scopes, and is not generally called out on spec sheets. Despite some having 2" focusers, most Cats below 8" have Baffle Tubes topping out at 27mm, which is the maximum for 1.25" EPs. Any 2" EP with a Field Stop larger than 27mm won't receive the full light cone, and even max field 1.25" EP's will likely vignette to some degree
Hope it prevents a few regrettable purchases. Field of view calculators don’t work well for catadioptrics. Focusing by moving the primary mirror and restrictions in the optical path aren’t factored in
This is NOT true, read my longer reply to the other guy who commented "just take a picture " As long as the rear baffle is NOT OBSTRUCTED, as in the case of 10" and larger SCTs with 3.25" rear cells but sold with a 2" sct thread step down plate, which obstructs the rear baffle, and thread on SCT diagonals or microfocuser attached to the 2" thread plate, that further obstruct the baffle. You will get a fully illuminated field with even the widest 2" eyepieces. On top of that, even with the obstructed baffle, the image will appear to be fully illuminated as far as background sky, but stars in the outer portion of the field will be dimmer or not visible. You can. Check for this by defocusing, and if the outer donuts are cut off and not full circles, then you are being obstructed. This is why the Peterson eye opener was created, as well as other solutions like AP visual backs, and 3.25" mount plates for microfocusers or direct to CCD image train, being available in both meade and celestron thread pitch. The celestron pitch can fit a meade, but the meade won't work on a celestron (my jmi for my c11 wasn't stolen when the rest of my stuff was, and it works fine on the older 10" meade I use now). I have used 2" on scopes all the way down to a 127mm mak. On a 90mm mak is where I finally could detect vignetting on 2" eyepiece, but the unvignetted part if the field was still wider than possible with 1.25". I was also in astronomy sales for 5 years, and spent a good deal of time on the phone or in email fighting this common internet astronomy forum misinformation, and sold countless 2" upgrades for 5 6 and 8" scts, as well as 5 and 6 inch maks, and they DIDN'T get returned, because it works VERY well. The simple "logic" of "rear baffle too small, won't work", does not take into account that light is a cone, not a pipe, and the narrower the cone, like in f10 and slower scopes, the less of an issue the baffle size creates. As long as that light cone is not choked off like it is when the 2" plate is not removed from larger SCTs. This has been one of several common myths and misconceptions that have propagated on the internet since probably a decade before I finally took the deep dive into the hobby shortly after new years 2004, having had some previous experience since 1994 via community College astronomy and observational astronomy lab courses which I used for my science requirements. The general astronomy course had a field trip to a club dark site with an observatory with a 22" cassegrajn, and I later joined the club to gain access to the site and star parties. The lab class at the other campus a couple or few years later, had a rooftop observatory with a ton of open piers as well for the C8s we would use for observational labs. As well as a dark site field trip where they carted out a 16" EQ newtonian. From the club site, I manged a decent film astrophoto of m42 through the 22", some.lunar work through the C11 and C14 that were at that time also in the observatory with the 22", as well as killer piggybacked shots of comet hyakutake in 1996 on top of a member's 6" refractor, manually guiding on the comet nucleus itself, through the refractor since it was moving so fast. But I didn't fully jump in and start getting my own scopes and big binos until almost 10 years after the first class, and 10 years after the comet I started working at one of the top dealers, which put me on the phone with tons of people who had heard tons of misinformation. You can't fight it all, and it is still propagated, and things have only gotten worse as things like flat earth and right wing conspiracy theories have become mainstream.... the "you can't use 2" eyepieces " conspiracy theory is harmless by comparison :) But it is still misinformation nonetheless
"I have found that a 100° field of view is simply too much for me; I don't feel comfortable with it. However, around 68° or more should be suitable, even for observing planets. I have found my comfort zone to be between approximately 70° and 82°."
I am interested to buy explore scientific 127/1900 Mak Cassegrain telescope . I'm interested in both planetary and dso observation. So, is it better to attach 2inch SCT adapter and use angeleyes 40mm 2inch eyepiece and 2" diagonal? Or Celestron omni plossl eyepiece 40mm,1.25," Along with mirror star diagonal 1.25" ? Waiting for your Expert suggestion.
@smandal123 It depends on the diameter of the opening at the back of the C5. That telescope was originally designed to have a 35mm opening in which case the use of 2" eyepieces won't lead to strong vignetting. But in general, the C5 won't be able to fully illuminate a 2" eyepiece with a long focal length. If every last degree of true field of view is very important to you, then go the 2" route. But I would recommend sticking to 1.25" eyepieces and adapters. Get a 40mm Plössl and a quality mirror diagonal. Worst case you will lose a tiny bit of FOV, and instead you could get better 1.25" components.
I'm sorry, I would like to ask you an off topic question: What camera do you use for your video? The 4K image is very crisp, even with the UA-cam compression. Thank you for your video, thumbs up from Montréal!
Finally one UA-camr tells the real reason about barrel sizes. All others are talking about it being an advantage instead of it being just part of the specifications. Thank hoy!
Good example, the AstroTech XWA 100* 2in eyepeices. Only the 20mm is 2in only. The rest (13mm,9mm,7mm, 5mm) can be used as both 2in and 1.25in. But, just because they can fit a 1.25" doesnt mean they should. Some scopes may cause vignette because the field of view is bigger than the incoming light cone.
This is only true if the scope's intended light cone is obstructed where it is wider, as in the case of 10" or larger SCTs that have a 3.25" rear cell stepped down to 2", and usually with almost 1/4" thick metal where those threads are. Common in meade 10 12 and 14" scopes, and C11s and C14s (though old ones had proper clear aperture on the stock 2" diagonal) When any 2" diagonal , visual back or microfocuser is attached in this way, the light cone is choked off and stars become fainter or invisible in the outer part of the field even if the background sky appears to be evenly illuminated to the edge. On 5 6 and 8", and IIRC, 9.25" scts, which only have a rear baffle smaller than the 2" threads, there is no issue at all with the widest 2" eyepieces, since the intended light cone is not obstructed, and the focal ratio is slow enough to where the narrow cone can still illuminate the field. I have used (and sold) 2" eyepieces down to 127mm maks, and didn't start to see any vignetting till I tried it on a 90mm, and in that case it only showed up in the widest 2" eyepieces, like 30mm UW80 and 40-42mm superwides. With a 30 superwide it wasn't as much of an issue. The most common eyepiece I sold as a first 2" for an sct back then (2006-2011) was the 40mm william optics swan. And many a nexstar 5, 6 and 8 customer were very happy with the results.
Also, ALL 1.25/2" hybrid barrel eyepieces are only 1.25" optically, the 2" barrel is just mechanical due to the large size of the eyepieces. There's no difference whether you use them as 2" or 1.25" eyepieces
I use a 10x microscope eyepiece and it work very well! It cost around 20$ on Aliexpress (10x magnification for a microscope and a 24mm wide lens. I've calculated the focal around 16mm). I get a 60 degree field of view with my microscope eyepiece on my +90 years old 11 inch 2000mm focal Newtonian telescope. This 10x microscope eyepiece as a focal length of about 16mm and the barrel is only 23mm (or 15/16 inch). It's way smaller than a 2" or even a 1.25" but I can get an astonishing view of the moon. She take 90% of the viewing field. I don't have a focuser yet, so I can slide the microscope eyepiece sideway in the 1.25" hole to get different area on the moon (or to keep a planet in frame). Maybe if you have a shorter F/d you need an eyepiece with more internal correction? But I'm fine.
I’ve truly enjoyed every video of yours I’ve watched so far. Definitely getting through them all. Anyway I purchased our first telescope recently and went with a Celestron - StarSense Explorer 8-inch Dobsonian Smartphone App-Enabled Telescope. I spontaneously purchased a Tele Vue 24 mm Panoptic and a Tele Vue 9 mm Nagler. I was thinking of getting either their 2x Barlow or a third eyepiece to be content for a couple years? If I did go with a third Tele Vue eyepiece which would you recommend to complement the two I have and my telescope? Thanks again.
@TransformersHoarder Thank you! I'm glad, you are enjoying my videos. A quality 2x Barlow would be a good choice. The only thing to consider here is the compatibility with mirror/prism diagonals since the 2x Barlow from TV is so long. If you think you are going to get a second telescope in the future that uses a diagonal, then you might consider a 4mm DeLite instead of the Barlow.
can a 2in eyepeice and 1.25in fit on the same telescope? or is that measurement measuring how big the hole is in the telescope for the eyepeice to fit in?
@elijahpawlicki7973 1.25" and 2" refer to the diameter of the eyepiece barrel and both sizes can be used with one telescope, but you will need a reducer adapter from 2" to 1.25" in order to use the smaller size eyepieces. Telescopes that support 2" eyepieces usually come with such an adapter.
Peace Bogdan. Very much enjoy your videos and learn alot. Ive had my "Apertura AD10" for some time now and I've yet to buy any eye pieces but now im going to. Can you give me your best advice on which eye pieces i should get for planetary viewing and looking at DSO. Thanks 👍🏾
@knowledge_gangsta Hi! Glad you are enjoying my videos. I recommend keeping the 30mm EP the telescope came with for now and focusing on the shorter focal lengths. Here a good choice would be the 8.5mm 82° from Explore Scientific and a 2x Barlow either from Explore Scientific or Tele Vue. This would give you two magnification options for planetary observations. Alternatively you could go for a 4mm and a 7mm Tele Vue DeLite for maximum image quality. Later on you could get a 2x Barlow as well to use with the 7mm EP and thus have three high magnification levels at your disposal.
Salut Bogdan, mi-am comandat si eu montura Svbony SV225 pe care vad ca o ai si tu. Poti sa imi spui te rog, se potriveste pe un trepied normal sau doar pe cele cu surub 3/8 ? Cu surub 3/8 am gasit doar doua trepiede de vanzare Skywatcher Adventurer cu 100 euro si cu picioare din aluminiu de 1.25 inch ce nu pare tare solid si inca un trepied cu 200 euro si picioare din otel de 1.75 inch. Trepiedul tau din aluminiu e cu surub 3/8 sau M10 ? Multumesc!
@supermario8416 Salut! Sv225 are nevoie de un trepied cu surub de 3/8, insa sunt adaptoare pentru a trece de la 1/4 la 3/8 (www.amazon.de/-/en/Greluma-Convert-Adapter-Tripod-Monopod/dp/B08K38V8WV/ref=sr_1_6). Sunt trepiede de camera la care se poate da jos capul flexibil, lasand doar un surub de 3/8 in urma. Pe ala poti monta un cap de stativ pentru telescop fara probleme. Trepiedul meu e cu surub de 3/8".
@@BogdanDamian Multumesc pt raspuns. Ar fi interesant un video review pt Sv225. Cred ca e cam cea mai buna montura AZ din cate am vazut, peste ES / Bresser Twilight.
@Bogdan excuse my offtopic question. Do you see little bit of chromatic aberation with sv503 on Jupiter, with the svbony 9mm gold I get just a little bit rarely but with svbony 7-21mm zoom I get some more especially if I look from an angle. I did my observations from the balcony on an illuminated street but with no light direcly hitting the telescope lens.
@PauI__ Depending on the eyepieces I use, there is always a certain amount of chromatic aberrations visible when observing very bright targets like Jupiter. The telescope's objective can only do so much in terms of correcting the light and if the eyepiece's lenses aren't well corrected, the whole system might show some aberrations. In your case it seems like the 9mm Gold has better corrected lenses than the 7-21mm zoom.
I have never used a 2",or 3", eyepiece just 1.25"and years ago the .96"ones in an old Japanese telescope I had.As I recall .96"had a much narrower field of view compared with a similar power 1.25".
There were a few wide field .965 eyepieces, as long as the focal length was short enough, say 18mm compared to 24mm, they could still display a larger apparent field. But these weren't common
just picked up an 8" dob, what eyepiece sizes would you recommend I should have in my arsenal? not too worried about price either. any help is greatly appreciated, clear skies!
@PToastman Congrats on your new telescope! I would recommend a 7mm, a 9mm Tele Vue DeLite and a 2x Barlow from Tele Vue or 2x Focal Extender from Explore Scientific. These would be for planetary observations. For DSOs look at a 31mm Nagler from Tele Vue or a 30mm 82° from Explore Scientific. Later if you feel the need to fill in the gap between 9 and 30mm, you could look at 24mm Panoptic from Tele Vue. Here is a more comprehensive List including links to the eyepieces in the video description: ua-cam.com/video/XN_c2nWgSGU/v-deo.html Hope this helps.
@@BogdanDamian thanks for the advice...just found out my wife ordered me 7mm Nagler & she found a 22mm Panoptic (on order). Thanks to your info, I'll know how to complete my arsenal. again, greatly appreciated & clear skies!
Don't forget the 21mm ethos and the 20mm xwa from William optics, stellarvue apm and others. The 20mm es100 starts to show bad edges at f5, I first noticed this in someone's 20" obsession, he had the ethos and I had the es100. Now I have the wo xwa and am extremely happy with it, much closer to the ethos
Super interesting, luckily I have a cc to translate this guy though, he speaks pretty much perfect English. I am hard of hearing so the different tones can garble the speech. OH WELL, I am looking into a super good BINOVIEWER which I would like to put 2" eye pieces. The binoviewer is over 1200 I believe and god knows that the 2" eye piece is almost twice as much as a 1.25. Huge money for such a in my oppinion, a upgrade for me. The more light theroy of a dobsonian might be a big plus because of the darker apperince in your eye pieces. So the more light for me just because of the REALLY GOOD Binoviewer and the most expencive eye pieces is the only way to go for me. A thousand dollars just for the binoviewer, needs comparible eye pieces of quality. Thank you.
I have several telescopes (414/1868 Dobson), (125/1560 Lichtenknecker), (102/714 H-alpha solar telescope DIY). To name a few for visual observation. For these, I need 2-inch eyepieces on the one hand, and on the other hand, since I also work with two binocular setups, 2x1.25" pairs. Oh, and by the way, I've now developed a preference for high-end equipment. That puts a strain on the finances, though ^^. My collection includes and will be further supplemented with a 2" 70mm Vixen Kellner, 2", 55mm Televue Plössl (I still have a Bresser), 41mm Panoptic (I don't have it yet), 2" 31mm Nagler type 5, 22mm Nagler type 5 (I don't have it yet), 17mm Nagler Type 4, 1.25" 2x 24mm Panoptic (getting one in the next few days), 1.25" 19mm Panoptic (I don't have it yet), 12.5mm Baader Morpheus 2x, 2x 9mm Baader Morpheus (I don't have it yet), two Baader Hyperion Mark IV Zoom eyepieces 8-24mm (I don't have it yet), 2x 6.5mm Baader Morpheus (I don't have it yet), 1x Baader Morpheus 4.5mm (I don't have it yet), one 3-8mm svbony Zoom, and one 3.5mm Televue Delos (I don't have it yet). I've sold all my budget eyepieces and plan to gradually acquire one by one at astro fairs and forums over the next 2-3 years ^^ Then I won't have to buy eyepieces for a very long time ^^. clear skies Felix
@dienachtwache Those are some nice telescopes and that's a long list of nice eyepieces to get. I have no trouble believing that it will put a strain on the finances ;) Good luck and clear skies!
I have a Nexstar 6SE, and have been considering replacing the diagonal with a 2" so I can get some wider FOV eyepieces. Not sure if this is worth it though, I've read that this can cause spherical aberration, and may not give great results. Is this correct? My 25mm 60° eyepiece is decent, would really like something like a 40mm though.
@GaddafiColonel If the opening at the end of the telescope is smaller in diameter than 2", then the beam of light coming from the telescope might not "fill out" the whole fov of the eyepiece. This will lead to vignetting (darkening of the edges of the fov).
@BogdanDamian not true at all, as long as the rear baffle is not obstructed as in the case of larger scts that ship with an obstructing 3.25" to 2" step down plate. And even in that case the result is not vignetting but the loss of fainter stars at the edge even if the background sky appears evenly illuminated, this is a common misconception propagated on the internet for decades.
I have two 26 mm eyepieces for my 6 inch f5 newtonian, one is 1.25 inch Plossl from Bresser, and the other one is 2 inch from Svbony. The 2 inch one has 70° FOV, but the extra FOV is strongly affected by coma. It means no optical benefit compared to its 1.25 inch version. Despite that I prefer the 2 inch eyepiece because of its ergonomics and comfort, because I can surround my eye with much wider rubber cover and have much larger piece of glass in front of my eye.
Yes, f/5 will have coma, but far the biggest reason for that lousy outer field image quality is that cheap old 5 element design from time when f/10 was pretty fast telescope being full of undercorrected aberrations. For good image quality in f/5 you want modern design 200 $/€ level eyepiece like 28mm UWA or 30mm Ultra Flat Field.
@tuunaes yeah, at f5 an erfle based design is more affected by its own astigmatism than the scope's coma. It was Al naglers invention of the paracorr that revealed astigmatism was the bigger culprit in his wide field 65 degree eyepieces, that led to the introduction of the panoptic
I just bought a new to me Obsession 20”F5 I was looking for a 15” but the 20” came up relatively close and I thought what the heck! Buy it! I invested in a bunch of new EPs Set 1 APM30 Morpheus 17.5 Morpheus 12.5 Morpheus 9 Set 2 Nagler 22 Nagler 17 Nagler 12 Haven’t used set 2 yet but set 1 used as 2” EPs is amazing! I only have 3 total hours since buying it but M42 shows green/teal/pink/rust color IC418 has a clear red ring surrounding light pink lacy haze with M12.5 Cant wait for galaxy season from Bortle 1
@georgewashington7444 The viewing experience with the 20" sure sounds amazing. Congrats on an excellent telescope! The eyepieces do match the telescope. Great selection! Clear skies!
A very wide field-of-view at high-magnification is really useful for planetary observations in a Dobsonian because you don't need to move the scope as frequently. You can enjoy the steady view of the planet as it moves across your wide field-of-view. It's also great for looking at the moon because you can see a lot more lunar landscape up-close. Just an observation. Great video! Explains a lot!
Ok, maybe you can help me because I'm completely confused and in way over my head. I just bought a "Celestron StarSense Explorer 114mm Tabletop Dobsonian" because my son loved looking out of his dad's telescope but he died and I have no clue what to do with it. So I bought another one that's got "cheats" that will help me help him look. It has a 114mm aperture and 450mm focal length. We live in a big city so I wanted something we could carry out while canping. Is there one eyepiece that you would suggest I add to what comes with it to help him see? It comes with 17mm and 11mm eyepieces. If you have any suggestions, I would very much like to hear them. Please and thank you... Also, it takes 1.5in eyepieces.
@franny5295 Hi! It's great that you brought your son a telescope. The one you chose is a good beginner model. The included eyepieces are okay for wider views and bigger objects like the Orion nebula. For planets like Jupiter, you will need more magnification. This you obtain using an eyepiece with a shorter focal length. In your case I would recommend a 3mm one like the 52° from explore scientific. The formula for magnification is the focal length of the telescope divided by the focal length of the eyepiece. With a 3mm eyepiece the telescope will deliver a 150x magnification. The maximum theoretical magnification for that telescope is roughly 2x 114 = 228x. Hope this helps.
Often the eyepieces that come with a telescope are a good focal length for it. Sometimes the best upgrade is buying better eyepieces to replace the ones that come with the telescope. Damian has a good video comparing eyepieces of different focal lengths at different price points. Don't feel like you 'must' upgrade either, if your son is happy with the eyepieces, they are good enough. You usually end up using two or three eyepieces at most.
As I understand it, the reason is that, unless you can hold your head perfectly still, you can't make full use of an exit pupil the size of your pupil. What happens when some of the light misses your pupil depends on the design of the eyepiece. It may cause effects like *kidney beaning.* This may make the eyepiece unusable in practice, if the view keeps blacking out partially. As I understnd it, eyepieces are different in this regard. Some punish head movement more, some dim more uniformly and gracefully. Too small of a beam may cause floaters, and other eye anatomy related issues, to become more visible. In general, viewing becomes less confortable with very small exit pupils.
Oh Jesus Christ put 2 EPs on a scope record it , and let us see the difference. Its not that hard . You can use a mirrorless micro 4/3 camera and mount it on EP , or take a dedicated Astro camera and mount it . let us see the difference .
@@davidtotten3042 i shell , and i will leave you with some information . Refractors can use even 50mm EP , even cheap ones , while Reflectors cant , this is due to the focuser tube , or secondary mirror making it impossible to capture wider field . So when i get 50mm EP , yeah i will show it and it will be on a refractor .
You don't need to record anything. 2" barrell *makes larger field of view possible** (at similar focal length), but it isn't guaranteed. It depends on the design of the eyepiece, if it makes use of the size. There's no inherent difference in brightness or contrast either. 2" may feel more confortable to view, but 'feelings' doesn't show on camera.
@@tietosanakirja not so correct ,2inch focuser will not give you wider FOV on anything except Refractor because the beam of light is limited by the reflecting mirror and the focuser tube , depending on the design .
Someone doesn't understand how things work. A lot of people don't, but assume they do. It is called the dunning Kruger effect and in this time you are making a fine example of it
I actually like wide FOV when observing planets because you can get some or all of the moons in. Nice to see the whole planetary system
@@TheSighphiguy That's why 100 degree eyepieces exist, you can see the full moon at 200X with an APM 100 degree or 110 degree eyepiece depending on the telescope. The drift time on planets is insane.
Baffle Tube Diameter is another factor to consider when selecting EPs for Catadioptric scopes, and is not generally called out on spec sheets. Despite some having 2" focusers, most Cats below 8" have Baffle Tubes topping out at 27mm, which is the maximum for 1.25" EPs. Any 2" EP with a Field Stop larger than 27mm won't receive the full light cone, and even max field 1.25" EP's will likely vignette to some degree
@oninoyakamo That's a good point. Thanks for your input!
Hope it prevents a few regrettable purchases.
Field of view calculators don’t work well for catadioptrics. Focusing by moving the primary mirror and restrictions in the optical path aren’t factored in
This is NOT true, read my longer reply to the other guy who commented "just take a picture "
As long as the rear baffle is NOT OBSTRUCTED, as in the case of 10" and larger SCTs with 3.25" rear cells but sold with a 2" sct thread step down plate, which obstructs the rear baffle, and thread on SCT diagonals or microfocuser attached to the 2" thread plate, that further obstruct the baffle. You will get a fully illuminated field with even the widest 2" eyepieces.
On top of that, even with the obstructed baffle, the image will appear to be fully illuminated as far as background sky, but stars in the outer portion of the field will be dimmer or not visible. You can. Check for this by defocusing, and if the outer donuts are cut off and not full circles, then you are being obstructed.
This is why the Peterson eye opener was created, as well as other solutions like AP visual backs, and 3.25" mount plates for microfocusers or direct to CCD image train, being available in both meade and celestron thread pitch. The celestron pitch can fit a meade, but the meade won't work on a celestron (my jmi for my c11 wasn't stolen when the rest of my stuff was, and it works fine on the older 10" meade I use now).
I have used 2" on scopes all the way down to a 127mm mak. On a 90mm mak is where I finally could detect vignetting on 2" eyepiece, but the unvignetted part if the field was still wider than possible with 1.25".
I was also in astronomy sales for 5 years, and spent a good deal of time on the phone or in email fighting this common internet astronomy forum misinformation, and sold countless 2" upgrades for 5 6 and 8" scts, as well as 5 and 6 inch maks, and they DIDN'T get returned, because it works VERY well.
The simple "logic" of "rear baffle too small, won't work", does not take into account that light is a cone, not a pipe, and the narrower the cone, like in f10 and slower scopes, the less of an issue the baffle size creates.
As long as that light cone is not choked off like it is when the 2" plate is not removed from larger SCTs.
This has been one of several common myths and misconceptions that have propagated on the internet since probably a decade before I finally took the deep dive into the hobby shortly after new years 2004, having had some previous experience since 1994 via community College astronomy and observational astronomy lab courses which I used for my science requirements. The general astronomy course had a field trip to a club dark site with an observatory with a 22" cassegrajn, and I later joined the club to gain access to the site and star parties.
The lab class at the other campus a couple or few years later, had a rooftop observatory with a ton of open piers as well for the C8s we would use for observational labs. As well as a dark site field trip where they carted out a 16" EQ newtonian.
From the club site, I manged a decent film astrophoto of m42 through the 22", some.lunar work through the C11 and C14 that were at that time also in the observatory with the 22", as well as killer piggybacked shots of comet hyakutake in 1996 on top of a member's 6" refractor, manually guiding on the comet nucleus itself, through the refractor since it was moving so fast.
But I didn't fully jump in and start getting my own scopes and big binos until almost 10 years after the first class, and 10 years after the comet I started working at one of the top dealers, which put me on the phone with tons of people who had heard tons of misinformation.
You can't fight it all, and it is still propagated, and things have only gotten worse as things like flat earth and right wing conspiracy theories have become mainstream.... the "you can't use 2" eyepieces " conspiracy theory is harmless by comparison :)
But it is still misinformation nonetheless
@@BogdanDamian common myth in the hobby, I just posted a long explanation
@@k.h.1587 You were doing so well until you got to "right wing conspiracy theories" ..........
"I have found that a 100° field of view is simply too much for me; I don't feel comfortable with it. However, around 68° or more should be suitable, even for observing planets. I have found my comfort zone to be between approximately 70° and 82°."
Great video as always I’ve learned a lot from you in two years but still have a long way to go so thanks bogdan!🤙🏻
I am interested to buy explore scientific 127/1900 Mak Cassegrain telescope .
I'm interested in both planetary and dso observation.
So, is it better to attach 2inch SCT adapter and use angeleyes 40mm 2inch eyepiece and 2" diagonal?
Or
Celestron omni plossl eyepiece 40mm,1.25,"
Along with mirror star diagonal 1.25" ?
Waiting for your Expert suggestion.
@smandal123 It depends on the diameter of the opening at the back of the C5. That telescope was originally designed to have a 35mm opening in which case the use of 2" eyepieces won't lead to strong vignetting.
But in general, the C5 won't be able to fully illuminate a 2" eyepiece with a long focal length. If every last degree of true field of view is very important to you, then go the 2" route. But I would recommend sticking to 1.25" eyepieces and adapters. Get a 40mm Plössl and a quality mirror diagonal. Worst case you will lose a tiny bit of FOV, and instead you could get better 1.25" components.
I'm sorry, I would like to ask you an off topic question:
What camera do you use for your video? The 4K image is very crisp, even with the UA-cam compression.
Thank you for your video, thumbs up from Montréal!
@alexandrevaliquette3883 I am only using my phone - a Google Pixel 7 - to record the video in 4k30.
2" barrel won't let in any more light per surface area unit at focal plane.
It only lets in bigger piece of image projected by telescope's objective.
Finally one UA-camr tells the real reason about barrel sizes. All others are talking about it being an advantage instead of it being just part of the specifications. Thank hoy!
Great video as always, a actually found out something new
Good example, the AstroTech XWA 100* 2in eyepeices. Only the 20mm is 2in only. The rest (13mm,9mm,7mm, 5mm) can be used as both 2in and 1.25in.
But, just because they can fit a 1.25" doesnt mean they should. Some scopes may cause vignette because the field of view is bigger than the incoming light cone.
This is only true if the scope's intended light cone is obstructed where it is wider, as in the case of 10" or larger SCTs that have a 3.25" rear cell stepped down to 2", and usually with almost 1/4" thick metal where those threads are. Common in meade 10 12 and 14" scopes, and C11s and C14s (though old ones had proper clear aperture on the stock 2" diagonal)
When any 2" diagonal , visual back or microfocuser is attached in this way, the light cone is choked off and stars become fainter or invisible in the outer part of the field even if the background sky appears to be evenly illuminated to the edge.
On 5 6 and 8", and IIRC, 9.25" scts, which only have a rear baffle smaller than the 2" threads, there is no issue at all with the widest 2" eyepieces, since the intended light cone is not obstructed, and the focal ratio is slow enough to where the narrow cone can still illuminate the field.
I have used (and sold) 2" eyepieces down to 127mm maks, and didn't start to see any vignetting till I tried it on a 90mm, and in that case it only showed up in the widest 2" eyepieces, like 30mm UW80 and 40-42mm superwides. With a 30 superwide it wasn't as much of an issue.
The most common eyepiece I sold as a first 2" for an sct back then (2006-2011) was the 40mm william optics swan. And many a nexstar 5, 6 and 8 customer were very happy with the results.
Also, ALL 1.25/2" hybrid barrel eyepieces are only 1.25" optically, the 2" barrel is just mechanical due to the large size of the eyepieces. There's no difference whether you use them as 2" or 1.25" eyepieces
I use a 10x microscope eyepiece and it work very well! It cost around 20$ on Aliexpress (10x magnification for a microscope and a 24mm wide lens. I've calculated the focal around 16mm).
I get a 60 degree field of view with my microscope eyepiece on my +90 years old 11 inch 2000mm focal Newtonian telescope. This 10x microscope eyepiece as a focal length of about 16mm and the barrel is only 23mm (or 15/16 inch). It's way smaller than a 2" or even a 1.25" but I can get an astonishing view of the moon. She take 90% of the viewing field.
I don't have a focuser yet, so I can slide the microscope eyepiece sideway in the 1.25" hole to get different area on the moon (or to keep a planet in frame).
Maybe if you have a shorter F/d you need an eyepiece with more internal correction? But I'm fine.
So unique!
So original!!
Never heard of it!!!
I’ve truly enjoyed every video of yours I’ve watched so far. Definitely getting through them all. Anyway I purchased our first telescope recently and went with a Celestron - StarSense Explorer 8-inch Dobsonian Smartphone App-Enabled Telescope. I spontaneously purchased a Tele Vue 24 mm Panoptic and a Tele Vue 9 mm Nagler. I was thinking of getting either their 2x Barlow or a third eyepiece to be content for a couple years? If I did go with a third Tele Vue eyepiece which would you recommend to complement the two I have and my telescope? Thanks again.
@TransformersHoarder Thank you! I'm glad, you are enjoying my videos.
A quality 2x Barlow would be a good choice. The only thing to consider here is the compatibility with mirror/prism diagonals since the 2x Barlow from TV is so long. If you think you are going to get a second telescope in the future that uses a diagonal, then you might consider a 4mm DeLite instead of the Barlow.
can a 2in eyepeice and 1.25in fit on the same telescope? or is that measurement measuring how big the hole is in the telescope for the eyepeice to fit in?
@elijahpawlicki7973 1.25" and 2" refer to the diameter of the eyepiece barrel and both sizes can be used with one telescope, but you will need a reducer adapter from 2" to 1.25" in order to use the smaller size eyepieces. Telescopes that support 2" eyepieces usually come with such an adapter.
@BogdanDamian okay thank you so much! Does the 2in eyepiece let more light in?
@elijahpawlicki7973 Yes, because they feature longer focal lengths and therefore a wider field stop.
@@BogdanDamian awesome thank you! Any recommendations for a 2" adapter to fit a 1.25"?
@elijahpawlicki7973 No, just get one with a compression ring instead of bare screws for tightening the eyepiece. The brand is irrelevant.
Peace Bogdan. Very much enjoy your videos and learn alot. Ive had my "Apertura AD10" for some time now and I've yet to buy any eye pieces but now im going to. Can you give me your best advice on which eye pieces i should get for planetary viewing and looking at DSO. Thanks 👍🏾
@knowledge_gangsta Hi! Glad you are enjoying my videos. I recommend keeping the 30mm EP the telescope came with for now and focusing on the shorter focal lengths. Here a good choice would be the 8.5mm 82° from Explore Scientific and a 2x Barlow either from Explore Scientific or Tele Vue. This would give you two magnification options for planetary observations. Alternatively you could go for a 4mm and a 7mm Tele Vue DeLite for maximum image quality. Later on you could get a 2x Barlow as well to use with the 7mm EP and thus have three high magnification levels at your disposal.
Salut Bogdan, mi-am comandat si eu montura Svbony SV225 pe care vad ca o ai si tu. Poti sa imi spui te rog, se potriveste pe un trepied normal sau doar pe cele cu surub 3/8 ? Cu surub 3/8 am gasit doar doua trepiede de vanzare Skywatcher Adventurer cu 100 euro si cu picioare din aluminiu de 1.25 inch ce nu pare tare solid si inca un trepied cu 200 euro si picioare din otel de 1.75 inch. Trepiedul tau din aluminiu e cu surub 3/8 sau M10 ? Multumesc!
@supermario8416 Salut! Sv225 are nevoie de un trepied cu surub de 3/8, insa sunt adaptoare pentru a trece de la 1/4 la 3/8 (www.amazon.de/-/en/Greluma-Convert-Adapter-Tripod-Monopod/dp/B08K38V8WV/ref=sr_1_6).
Sunt trepiede de camera la care se poate da jos capul flexibil, lasand doar un surub de 3/8 in urma. Pe ala poti monta un cap de stativ pentru telescop fara probleme.
Trepiedul meu e cu surub de 3/8".
@@BogdanDamian Multumesc pt raspuns. Ar fi interesant un video review pt Sv225. Cred ca e cam cea mai buna montura AZ din cate am vazut, peste ES / Bresser Twilight.
@supermario8416 Mai trebuie doar sa astepti pana vineri ;)
@Bogdan excuse my offtopic question. Do you see little bit of chromatic aberation with sv503 on Jupiter, with the svbony 9mm gold I get just a little bit rarely but with svbony 7-21mm zoom I get some more especially if I look from an angle. I did my observations from the balcony on an illuminated street but with no light direcly hitting the telescope lens.
@PauI__ Depending on the eyepieces I use, there is always a certain amount of chromatic aberrations visible when observing very bright targets like Jupiter. The telescope's objective can only do so much in terms of correcting the light and if the eyepiece's lenses aren't well corrected, the whole system might show some aberrations. In your case it seems like the 9mm Gold has better corrected lenses than the 7-21mm zoom.
@@BogdanDamian thank you for the details, being new to this I always wonder if things I see are normal or not :)
Well explained. 👍
I have never used a 2",or 3", eyepiece just 1.25"and years ago the .96"ones in an old Japanese telescope I had.As I recall .96"had a much narrower field of view compared with a similar power 1.25".
There were a few wide field .965 eyepieces, as long as the focal length was short enough, say 18mm compared to 24mm, they could still display a larger apparent field. But these weren't common
just picked up an 8" dob, what eyepiece sizes would you recommend I should have in my arsenal? not too worried about price either. any help is greatly appreciated, clear skies!
@PToastman Congrats on your new telescope! I would recommend a 7mm, a 9mm Tele Vue DeLite and a 2x Barlow from Tele Vue or 2x Focal Extender from Explore Scientific. These would be for planetary observations. For DSOs look at a 31mm Nagler from Tele Vue or a 30mm 82° from Explore Scientific. Later if you feel the need to fill in the gap between 9 and 30mm, you could look at 24mm Panoptic from Tele Vue.
Here is a more comprehensive List including links to the eyepieces in the video description: ua-cam.com/video/XN_c2nWgSGU/v-deo.html
Hope this helps.
@@BogdanDamian thanks for the advice...just found out my wife ordered me 7mm Nagler & she found a 22mm Panoptic (on order). Thanks to your info, I'll know how to complete my arsenal. again, greatly appreciated & clear skies!
Don't forget the 21mm ethos and the 20mm xwa from William optics, stellarvue apm and others.
The 20mm es100 starts to show bad edges at f5, I first noticed this in someone's 20" obsession, he had the ethos and I had the es100. Now I have the wo xwa and am extremely happy with it, much closer to the ethos
Super interesting, luckily I have a cc to translate this guy though, he speaks pretty much perfect English. I am hard of hearing so the different tones can garble the speech. OH WELL, I am looking into a super good BINOVIEWER which I would like to put 2" eye pieces. The binoviewer is over 1200 I believe and god knows that the 2" eye piece is almost twice as much as a 1.25. Huge money for such a in my oppinion, a upgrade for me. The more light theroy of a dobsonian might be a big plus because of the darker apperince in your eye pieces. So the more light for me just because of the REALLY GOOD Binoviewer and the most expencive eye pieces is the only way to go for me. A thousand dollars just for the binoviewer, needs comparible eye pieces of quality. Thank you.
I have several telescopes (414/1868 Dobson), (125/1560 Lichtenknecker), (102/714 H-alpha solar telescope DIY). To name a few for visual observation. For these, I need 2-inch eyepieces on the one hand, and on the other hand, since I also work with two binocular setups, 2x1.25" pairs. Oh, and by the way, I've now developed a preference for high-end equipment. That puts a strain on the finances, though ^^. My collection includes and will be further supplemented with a 2" 70mm Vixen Kellner, 2", 55mm Televue Plössl (I still have a Bresser), 41mm Panoptic (I don't have it yet), 2" 31mm Nagler type 5, 22mm Nagler type 5 (I don't have it yet), 17mm Nagler Type 4, 1.25" 2x 24mm Panoptic (getting one in the next few days), 1.25" 19mm Panoptic (I don't have it yet), 12.5mm Baader Morpheus 2x, 2x 9mm Baader Morpheus (I don't have it yet), two Baader Hyperion Mark IV Zoom eyepieces 8-24mm (I don't have it yet), 2x 6.5mm Baader Morpheus (I don't have it yet), 1x Baader Morpheus 4.5mm (I don't have it yet), one 3-8mm svbony Zoom, and one 3.5mm Televue Delos (I don't have it yet). I've sold all my budget eyepieces and plan to gradually acquire one by one at astro fairs and forums over the next 2-3 years ^^ Then I won't have to buy eyepieces for a very long time ^^.
clear skies
Felix
@dienachtwache Those are some nice telescopes and that's a long list of nice eyepieces to get. I have no trouble believing that it will put a strain on the finances ;) Good luck and clear skies!
w tej chwili to więcej nie masz , jak masz
Thank you.
I have a Nexstar 6SE, and have been considering replacing the diagonal with a 2" so I can get some wider FOV eyepieces. Not sure if this is worth it though, I've read that this can cause spherical aberration, and may not give great results. Is this correct? My 25mm 60° eyepiece is decent, would really like something like a 40mm though.
@GaddafiColonel If the opening at the end of the telescope is smaller in diameter than 2", then the beam of light coming from the telescope might not "fill out" the whole fov of the eyepiece. This will lead to vignetting (darkening of the edges of the fov).
@@BogdanDamian Thank you!
the baffle tube in the 6se is too small to get any benefit from a 2” eyepiece.
@BogdanDamian not true at all, as long as the rear baffle is not obstructed as in the case of larger scts that ship with an obstructing 3.25" to 2" step down plate. And even in that case the result is not vignetting but the loss of fainter stars at the edge even if the background sky appears evenly illuminated, this is a common misconception propagated on the internet for decades.
@millsbobster not true. See my reply to video poster, and longer explanations on other comment threads
I have two 26 mm eyepieces for my 6 inch f5 newtonian, one is 1.25 inch Plossl from Bresser, and the other one is 2 inch from Svbony. The 2 inch one has 70° FOV, but the extra FOV is strongly affected by coma. It means no optical benefit compared to its 1.25 inch version. Despite that I prefer the 2 inch eyepiece because of its ergonomics and comfort, because I can surround my eye with much wider rubber cover and have much larger piece of glass in front of my eye.
Yes, f/5 will have coma, but far the biggest reason for that lousy outer field image quality is that cheap old 5 element design from time when f/10 was pretty fast telescope being full of undercorrected aberrations.
For good image quality in f/5 you want modern design 200 $/€ level eyepiece like 28mm UWA or 30mm Ultra Flat Field.
@@tuunaesThanks for explanation.
@tuunaes yeah, at f5 an erfle based design is more affected by its own astigmatism than the scope's coma.
It was Al naglers invention of the paracorr that revealed astigmatism was the bigger culprit in his wide field 65 degree eyepieces, that led to the introduction of the panoptic
I just bought a new to me Obsession 20”F5 I was looking for a 15” but the 20” came up relatively close and I thought what the heck! Buy it!
I invested in a bunch of new EPs
Set 1
APM30
Morpheus 17.5
Morpheus 12.5
Morpheus 9
Set 2
Nagler 22
Nagler 17
Nagler 12
Haven’t used set 2 yet but set 1 used as 2” EPs is amazing! I only have 3 total hours since buying it but M42 shows green/teal/pink/rust color IC418 has a clear red ring surrounding light pink lacy haze with M12.5
Cant wait for galaxy season from Bortle 1
@georgewashington7444 The viewing experience with the 20" sure sounds amazing. Congrats on an excellent telescope! The eyepieces do match the telescope. Great selection! Clear skies!
A very wide field-of-view at high-magnification is really useful for planetary observations in a Dobsonian because you don't need to move the scope as frequently. You can enjoy the steady view of the planet as it moves across your wide field-of-view. It's also great for looking at the moon because you can see a lot more lunar landscape up-close. Just an observation. Great video! Explains a lot!
Можете добавить Русские субтитры. Я любитель астроном но плохо знаю английский. А ваш канал интересен, много полезного.
Ok, maybe you can help me because I'm completely confused and in way over my head. I just bought a "Celestron StarSense Explorer 114mm Tabletop Dobsonian" because my son loved looking out of his dad's telescope but he died and I have no clue what to do with it. So I bought another one that's got "cheats" that will help me help him look. It has a 114mm aperture and 450mm focal length. We live in a big city so I wanted something we could carry out while canping. Is there one eyepiece that you would suggest I add to what comes with it to help him see? It comes with 17mm and 11mm eyepieces. If you have any suggestions, I would very much like to hear them. Please and thank you...
Also, it takes 1.5in eyepieces.
@franny5295 Hi! It's great that you brought your son a telescope. The one you chose is a good beginner model. The included eyepieces are okay for wider views and bigger objects like the Orion nebula. For planets like Jupiter, you will need more magnification. This you obtain using an eyepiece with a shorter focal length. In your case I would recommend a 3mm one like the 52° from explore scientific. The formula for magnification is the focal length of the telescope divided by the focal length of the eyepiece. With a 3mm eyepiece the telescope will deliver a 150x magnification. The maximum theoretical magnification for that telescope is roughly 2x 114 = 228x. Hope this helps.
Often the eyepieces that come with a telescope are a good focal length for it. Sometimes the best upgrade is buying better eyepieces to replace the ones that come with the telescope. Damian has a good video comparing eyepieces of different focal lengths at different price points.
Don't feel like you 'must' upgrade either, if your son is happy with the eyepieces, they are good enough. You usually end up using two or three eyepieces at most.
10mm hyperion
Its a surprise for clarity near a delos.
As a beginner, I found this extremely informative. Thank you for sharing
There are also 4" eyepieces
bigger is better
You say that the eye can utilize a 4-7mm exit beam but then say recommended 0.5 to 2.5mm. That is contradictory.
As I understand it, the reason is that, unless you can hold your head perfectly still, you can't make full use of an exit pupil the size of your pupil. What happens when some of the light misses your pupil depends on the design of the eyepiece. It may cause effects like *kidney beaning.* This may make the eyepiece unusable in practice, if the view keeps blacking out partially.
As I understnd it, eyepieces are different in this regard. Some punish head movement more, some dim more uniformly and gracefully.
Too small of a beam may cause floaters, and other eye anatomy related issues, to become more visible. In general, viewing becomes less confortable with very small exit pupils.
Oh Jesus Christ put 2 EPs on a scope record it , and let us see the difference. Its not that hard . You can use a mirrorless micro 4/3 camera and mount it on EP , or take a dedicated Astro camera and mount it . let us see the difference .
Sounds like you have a plan. Let us all know what you find out.
@@davidtotten3042 i shell , and i will leave you with some information . Refractors can use even 50mm EP , even cheap ones , while Reflectors cant , this is due to the focuser tube , or secondary mirror making it impossible to capture wider field .
So when i get 50mm EP , yeah i will show it and it will be on a refractor .
You don't need to record anything. 2" barrell *makes larger field of view possible** (at similar focal length), but it isn't guaranteed. It depends on the design of the eyepiece, if it makes use of the size.
There's no inherent difference in brightness or contrast either. 2" may feel more confortable to view, but 'feelings' doesn't show on camera.
@@tietosanakirja not so correct ,2inch focuser will not give you wider FOV on anything except Refractor because the beam of light is limited by the reflecting mirror and the focuser tube , depending on the design .
Someone doesn't understand how things work. A lot of people don't, but assume they do. It is called the dunning Kruger effect and in this time you are making a fine example of it