Astro Tutorial #1.9: Telescopes, Eyepieces & Magnification

[@eurodoc6343]

Are there any performance differences between a 2" and 1.5" diameter eyepiece?

[@catchingphotons]

I'm no expert on eyepieces: astronomy.stackexchange.com/questions/13889/what-are-the-advantages-and-disadvantages-of-a-2-inch-eyepiece-versus-a-1-25-inc Maybe there is some info for you! Clear skies!!

[@catchingphotons]

twitter.com/catchingphoton1/status/1458473870428606471?t=5X-qHIJIwGF51p3Z1tBd0A&s=19

[@ethanjogola2718]

ONLY 600 views??? Wth this is an amazing video!! Well done, this series is helping me out a lot getting into astronomy.

[@catchingphotons]

Thanks Ethan! That was a very encouraging comment! I'll continue this journey :-) It's a lot of fun! Greetings and clear skies! Chris

[@googlefuuplayad9055]

Now it's 4251 Views, with me 😊 Will be quite more soon, im sure

[@antoniofirenze]

You explained to me all there is on eyepieces. I'm going to rock the Physics presentation tomorrow!!

[@catchingphotons]

That's so cool! Good luck Antonio!

[@relativethoughts8032]

This is exactly what I am looking for, thank you.

[@catchingphotons]

You are very welcome Ayran! Glad the video was of any help! Clear skies!!

[@jimlahey5354]

Wow your videos are great. Best ones I can find regarding telescope basics.

[@catchingphotons]

Thank you very much! I hope these videos are just the beginning, I want to cover more topics in the order of depth and complexity: Hardware - the rig - image acquisition - processing... I hope you'll join me on this road ;) Greetings Chris

[@waynerichardson1706]

Another good video explaining the fundamentals well

[@catchingphotons]

Again: Thanks for your encouraging comments!

[@busheybushdawg]

Wow very good video - thanks for posting :)

[@catchingphotons]

You are very welcome! I really love creating those videos. Clear skies to you!

[@typhoonnamikaze1567]

" *two dot five* millimeter eyepiece" what a great way to read a decimal.

[@catchingphotons]

haha :-) it's the way I'm used to it, so I'll stick with that.

[@boblatshaw]

VERY Good explanation!

[@catchingphotons]

Thanks mate!!

[@satvikvarun6386]

✴️ *_PLEASE REPLY!_* Should I buy a telescope of *70mm* aperture with *Ramsden* eyepieces(20mm,12mm&4mm) OR *60mm* telescope with *1.25" Meade MA* eyepieces? eyepieces(26mm&9mm)? .... Both scopes have 2x barlow One has better arpeture & other has better eyepiece :( I mainly wanna view planets and some nebulas if possible

[@catchingphotons]

For nebulas it's the aperture (and the quality) for planetary its the focal length (and the quality). Trevor did a fantastic video just the other day about the first scope: kzbin.info/www/bejne/aXurpmepfNyfZrs Definitely watch it! Thumb rule: - buy @ astro retailer - buy proper scope on solid mount - 2 eyepieces (say 10/12 and 20/24) are a good start. - buy a smartphone holder for first images. Clear skies to you! -Chris

[@logically1028]

Man..that was brilliant...excellent explanation... Thanks a ton...you cleared lots of doubts no one else could... Thanks bro.. I was very much confused with how our eye sees objects and how lense see with that focal length issue and all..you cleared out.. But i wish if you could elaborate that how all the lines\light rays are coming from and where they are focused and how our vision system work with all these things..

[@catchingphotons]

I could do a follow up video. Would you mind to write down the bullet points for the content of interest? That would be great. Clear skies!!

[@logically1028]

@@catchingphotons oh..thank you so much...just give me some time so that I'm able to write it what i exactly need to learn... Sorry for the wording..I'm not native to English.. And once again thanks for being this nice..😊

[@satvikvarun6386]

*Please Reply* How are the H20mm and SR4mm in *"0.9inch"* ? Are they good. Do they have too much abberations? Do they provide bad images? What's the disadvantage of using 0.9"? *_Plese Reply in detail thanks_*

[@catchingphotons]

What brand - do you have any link? 4mm needs to be of best quality because otherwise the abberations will kill your viewing. Clear skies!

[@satvikvarun6386]

@@catchingphotons it's a "Ramsden" type. But I mainly wanna ask if 0.9" eyepieces are not worth it or should I invest little more and buy 1.25" ones?

[@rmotamayor]

Just thanks!!!

[@catchingphotons]

Your welcome! Clear skies!!

[@_tyler-_-]

Great video 🍻

[@catchingphotons]

Thanks man!

[@JsoProductionChannel]

Thank you

[@catchingphotons]

You're very welcome!!

[@texdoms]

Another great video! Thank you.

[@catchingphotons]

Thanks again for this encouraging comment Dominique! Those comments keep me going :-) Clear skies to you!

[@lwkett]

once again, a fantastic video. (i'm making comments, because your videos deserve more views than you get)

[@catchingphotons]

Thanks Lance for your encouraging comments!

[@sreekanthramesh777]

How about a 68 degree field of view, 25-30 mm eyepiece? Will it give good result for a 150/750 mm telescope?

[@catchingphotons]

A 25mm is something like a good standard for every scope. You can download "Stellarium" and enter your specifications - and see what's visible with this configuration. Does the Pleiades fit into the fov? Thereby get a feeling for the setup. Clear skies!!

[@SuperBuickregal]

Thank you again Chris, I look 👀 forward for the next video. How about some of your images done with music 🎼 like the moon 🌝 video along with some interesting 🧐 point about it. Thanks again Tom

[@catchingphotons]

Thanks Tom, yea I'm thinking about the "Vlog" section a lot. Thing is: My current equipment is kind of broken. So as long as the new rig hasn't arrived yet, there are no "fancy" images coming in. I' thinking about a short video - about my journey of imaging the solar system objects (Mercury - Venus - Mars - Jupiter - Saturn)... It might be fun. Let's see. Greetings and clear skies Chris

[@SuperBuickregal]

catchingphotons I am currently picking up pieces here and there. I am still in wide field with my digital mirrorless camera 📸. Since I like birds 🦅 I bought a 300mm f 2.8 for DSOs and use the Forex tracker when I make the leap.

[@catchingphotons]

Would you link some images? I realy like those wide field images a lot! Greetings Chris

[@SuperBuickregal]

@@catchingphotons Sure I have some nice shots from Australia.

[@catchingphotons]

Something like this? : kzbin.info/www/bejne/hofOi5mDg56niJo ;) Greetings Chris

[@sreekanthramesh777]

Superb content 👍👍❤️

[@catchingphotons]

Thanks a lot!!

[@davidbrandenburg8029]

when you look through a eyepiece and you see a star like pattern or faceting on the outer edge of the visible lens, can this be caused by them being out of collimation?. if so can you point me some where that can explain how to collimate these cheap focusers on my refractors? my meade 90mm ds90 and my 70mm celestron powerseeker are the only 2 telescopes I have this problem on. these same eyepieces work just fine on my newton and my 70mm wide field, with no ring or faceting visible!.

[@catchingphotons]

I certainly have no idea about eyepiece collimation. Try astronomyshed.co.uk - There are very skilled folks around there. Ask Nightspore, he is definitely within team “visual” :-) Maybe someone there will have a clue. Please reply here if you find the answer - I would be interested! Clear skies!

[@photonmaster4261]

Dear Chris . Does a focal reducer work with reflector telescopes. I have read alot about their use with Cassegrain and reftactors but nothing about newtonian reflectors. N.B focal length of my newtonian is 650mm with f/5. Thanks again for the best videos on youtube . Keep it going

[@catchingphotons]

Yes. In theory (!) a focal reducer is "just" another optical component that can be uses with any optical system. It will simply reduce the focal length of your system and fasten your scope. So wit 600mm FL and f5 using a 0.5 focal reducer will make your scope 300FL and f2.5. And the f-ratio will be the problem: See, if you fasten the scope, every optical imperfection will be magnified! Coma is a major problem within fast Newtonians, chromatic aberrations within fast refractors.... So your optics need to be near to perfect. My scope is f5 and I spot major star elongations within the image corners. I can use a f5 coma corrector but if I introduce a .5 focal reducer I'd need a f2.5 coma corrector - even more expensive. So: Yes , but... Greetings Chris

[@photonmaster4261]

@@catchingphotons thanks alot 🙏🏻

[@catchingphotons]

@@photonmaster4261 No worries :-)

[@jadejamanoharsinhi6335]

Sir are celestron powerseeker 127eq is good telescope?

[@catchingphotons]

Hey Jadeja, the question is: for what purpose? With 127mm aperture and 1000mm focal length you will be able to observe the planets, rings of Saturn, moons of Jupiter and craters of the moon. Using a smartphone adapter for the eyepiece you can even take cool images. With that aperture you will be able to see some faint ghosts of brighter deep sky objects, but don't expect much. For deep sky Astrophotography the Telescope is presumably not fitted to reach focus on the camera sensor and besides the mount will carry the scope for entry level visual observation but not for imaging (not sturdy enough and not motorized). All in all: a solid visual scope for entry level beginner observations of planets and moon. Clear skies!!

[@catchingphotons]

Please don't double post questions. You may as well contact me via Instagram or Twitter. Clear skies!

[@shedactivist]

Great tutorial, just what I was looking for, but it does leave me with a question. The eyepieces are designed to 'straighten' the light so the lens in your eye can do the final focusing. Cool, but how do I get different magnifications onto a camera sensor, which will not have a final lens attached. will eyepieces still work? A video on that subject would be brilliant. Great channel, subscribed with bell.

[@catchingphotons]

Hey Matt! Thanks for your encouraging comment! With your camera sensor at “prime focus” - so without any eyepiece - you can not change “magnification” - or the FOV as I tend to say. The way to go is to use either a “barlow” or a “reducer” lens. Those lenses will effectively boost or reduce your focal length and hence change the FOV. Use a 3x barlow on a 500mm scope will give you 1500mm FL and so on. You can enter “barlow-lenses” in Stellarium to play around with this. Barlow and reducer are next in line - I just need to finish my script :-) Meanwhile: here is a short schematic: upload.wikimedia.org/wikipedia/commons/thumb/3/37/Barlow_lens.svg/330px-Barlow_lens.svg.png The green line is the barlow - you see that the focal length “grew”. Greetings and clear skies!! Chris

[@shedactivist]

@@catchingphotons many thanks for replying so comprehensively. Barlow lenses it is then.

[@pubgplayer9064]

How to find eyepiece focal length please reply

[@michaelarcenas8165]

@PUBG player The focal lengths of eyepieces are indicated in the eyepieces themselves in millimeters (mm). An eyepiece with a 20mm marking means its focal length is 20 millimeters.

[@catchingphotons]

The focal length of the eyepiece is normally printed onto the eyepiece itself. So easy that. If you wanted to ask: How to find the fitting focal length for an eyepiece given a certain telescope? So you have scope X: What eyepieces to choose for that X telescope? -> The answer depends on the scope. The maximum magnification for the optical setup is given by the diameter/aperture of the scope. See the vid again for details. Say the max. magnification reachable with your scope is 200x - so if you have a 1000mm focal length scope you shouldn't go under 5mm eyepiece focal length, because 1000mm/5mm = 200x magnif. SO never triple the focal length with a 3x barlow and THEN use a 4mm eyepiece ;-) Good way to start: Choose a 25mm wide field eyepiece, and a 10mm eyepiece for closer shots and then maybe a 2x barlow. You can add the barlow to get 12.5mm and 5mm "equivalent" eyepieces - so to say. Clear skies to you! Chris

[@pubgplayer9064]

@@catchingphotons I have only eyepiece Lens

[@photonmaster4261]

Does a 2 inch eyepiece and 1.25 eyepiece of same focal length give different image quality.

[@catchingphotons]

In theory the 1,25“ and the 2“ eyepiece with the same focal length will give you the exact same angular magnification. Though the 2” eyepieces are much more pleasant to look through - due to their wider opening - and they offer a bigger field of view. So if you look through a good quality 2” it’s not like looking through a keyhole - but using a window instead :-) Greetings and clear skies! Chris

[@photonmaster4261]

@@catchingphotons thanks alot for your detailed reply . Thank you for all your videos

[@catchingphotons]

@@photonmaster4261You are welcome!

[@abdof100]

what about using 2 eyepiecs within the same telescope , it's like magnifying twice ?

[@catchingphotons]

Placing 2 eyepieces in a row wouldn't work due to the light paths. I wouldn't know how you'd attach them either way. If you want 2x magnification use eyepieces with 1/2 the focal length. Clear skies!

[@abdof100]

I was thinking about placing the second eyepiece inside the telescope behind the second miror. need more practice as last time it didn't work : confused image but there is some hope. thanks for the feed back

[@catchingphotons]

@@abdof100 I have never heard about something like this and (due to the light paths inside a scope) are a bit sceptical about that. Let me hear if you get anywhere with that. Greetings Chris

[@Mandragara]

Would a 4.7mm eyepiece with a 1200mm focal length scope be appropriate, or overmagnified? This is about 255x

[@catchingphotons]

What is the aperture of your scope? Clear skies!