Page 1 of 5 123 ... LastLast
Results 1 to 10 of 49
Like Tree22Likes

Thread: eyepiece advice for DSO viewing for my humble scope

  1. #1
    mruhomau's Avatar
    mruhomau is offline Bright Giants
    Points: 4,197, Level: 43
    Level completed: 65%, Points required for next Level: 53
    Overall activity: 4.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Gallery Achievement!
    Join Date
    Jul 2016
    Location
    Oakville
    Posts
    270
    Points
    4,197
    Level
    43
    Thanks
    72
    Thanked 7x 7 Posts

    Default eyepiece advice for DSO viewing for my humble scope



    Hi everyone,

    I'd like to first put my question into perspective and a quick intro of my accessories and what I am trying to achieve. In the month of July, I got my first scope and I've been using it at least a few times every week since then. So I am starting to learn about the planets, sky etc etc. Its a celestron astromaster 130 EQ, i.e 5 inch of aperture, 650 mm of focal length which makes it an F/5 scope. It has a focuser size of 1.25. It came with a 20mm and a 10mm stock eyepiece from celestron and I also purchased a couple of high magnification of loss eyepieces. I mainly use them for planet viewing since the view is too narrow for DSO

    I am now interested in DSO viewing and my question below will be in two parts in order for me to get help in picking a new eyepiece. Please note that I am seeing this as a lifetime investment ( for my current scope and future reflector scope few years from now), so I might be making a small effort in digging in a little bit of extra bucks for a good and durable eyepiece. I also need something with a descent true field of view as I am still a beginner and I am assuming it will make it easier for me to navigate the sky and try to recognize which DSO that I am looking at. As most of you would probably guess, half of the time, there is trial and error (looking at stellarium, maps and back and forth in the sky like 20 times) in me trying to find something :


    part 1 - I am looking for an eyepiece in the 15 to 20 mm range, what would be a good eyepiece size for my scope in relative to DSO viewing and magnification ? From my understanding, different DSO varies from one another in terms of magnitude and surface brightness which might require different eyepiece sizes. But I guess what I am looking for is something that would be a good fit for my scope in getting started with DSO viewing and that will allow me to see most of the stuff that a beginner can learn to see. Please also feel free to suggest anything outside the 15 mm to 20 mm range. I just provided this range because its kind of a guess from my end that this is the range adequate for my scope for beginner DSO viewing

    part 2 - in relative to part 1 above, can anyone suggest a specific brand/ model ? for example I am looking at the following models

    (i) explore scientific 14mm 82 degrees

    (ii) explore scientific 20mm 68 degrees

    (iii) GSO superview eyepiece 20mm 68 degrees

    (iv) televue nagler type 5 82 degrees 16 mm

    (v) televue panoptic 19mm 68 degrees


    notice how I included the tele vues as last because of the price :S


    thank you everyone in advance for the help and advice
    j.gardavsky likes this.

  2. #2
    Ozman13's Avatar
    Ozman13 is offline HYPER GIANT
    Points: 29,217, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 20.0%
    Achievements:
    2 Posts Achievement5 Threads Achievement!20 Posts Achievement!365 Days+ Registered Achievement!50 Posts Achievement!
    Join Date
    Jun 2013
    Location
    Hopkinsville Kentucky
    Posts
    8,431
    Points
    29,217
    Level
    100
    Thanks
    170
    Thanked 2,238x 2,011 Posts

    Default Re: eyepiece advice for DSO viewing for my humble scope

    I have the ES EPs you quote here. Both are excellent. I have most of the 82s and all of the 68s. The reason I have the 68s is because some of my scopes only have a 1.25" focuser and they perform very, very well. I would lean toward the ES 20 68 for your purposes but the ES 14 82 would be excellent as well.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ACF 8"SCT,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    120, ES 102CF Apo triplet, ES AR102, ST100, ST90, Apex 90mm Mak, ST80, ETX60,
    Oberwerk BT-82XL-ED, 25x100s, 15x70s, 8x56s, Kasai 2.3x40s, Celestron AVX, CG4, SLT, LCM, Obie HD Parallel Bino mount
    Explore Scientific 82 degree and 68 degree EPs, Baader 9mm Ortho, Meade 5000 SWA EP set, many more various EPs, Baader
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    &SkyGlow, FringeKiller, SemiApo filters, Celestron UHC, Meade 4000 Nebular Filter, Kson OIII, DGM NPB and lots of astro stuff.

  3. The Following User Says Thank You to Ozman13 For This Useful Post:

    mruhomau (08-08-2016)

  4. #3
    mruhomau's Avatar
    mruhomau is offline Bright Giants
    Points: 4,197, Level: 43
    Level completed: 65%, Points required for next Level: 53
    Overall activity: 4.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Gallery Achievement!
    Join Date
    Jul 2016
    Location
    Oakville
    Posts
    270
    Points
    4,197
    Level
    43
    Thanks
    72
    Thanked 7x 7 Posts

    Default Re: eyepiece advice for DSO viewing for my humble scope

    thank you Ozman 13

    question : the 20mm would give me a magnification of only 32.5 . would that be fine ? or would something in the 40X be more of an "all rounder " in terms of DSO viewing ?

  5. #4
    Ozman13's Avatar
    Ozman13 is offline HYPER GIANT
    Points: 29,217, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 20.0%
    Achievements:
    2 Posts Achievement5 Threads Achievement!20 Posts Achievement!365 Days+ Registered Achievement!50 Posts Achievement!
    Join Date
    Jun 2013
    Location
    Hopkinsville Kentucky
    Posts
    8,431
    Points
    29,217
    Level
    100
    Thanks
    170
    Thanked 2,238x 2,011 Posts

    Default Re: eyepiece advice for DSO viewing for my humble scope

    Quote Originally Posted by mruhomau View Post
    thank you Ozman 13

    question : the 20mm would give me a magnification of only 32.5 . would that be fine ? or would something in the 40X be more of an "all rounder " in terms of DSO viewing ?
    That would be a point of personal preference. For me, I would most likely prefer the lower magnification concerning DSO viewing with your scope. For some DSOs I would then want an increase in magnification, but that would probably be uping it to closer to 60-70x instead of only to 40x. What I would probably be most interested in would be the ES 68s 24, 20, 16mm and a good 2x Barlow turning the EPs into 12, 10, and 8 giving you a wide and excellent coverage.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ACF 8"SCT,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    120, ES 102CF Apo triplet, ES AR102, ST100, ST90, Apex 90mm Mak, ST80, ETX60,
    Oberwerk BT-82XL-ED, 25x100s, 15x70s, 8x56s, Kasai 2.3x40s, Celestron AVX, CG4, SLT, LCM, Obie HD Parallel Bino mount
    Explore Scientific 82 degree and 68 degree EPs, Baader 9mm Ortho, Meade 5000 SWA EP set, many more various EPs, Baader
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    &SkyGlow, FringeKiller, SemiApo filters, Celestron UHC, Meade 4000 Nebular Filter, Kson OIII, DGM NPB and lots of astro stuff.

  6. The Following User Says Thank You to Ozman13 For This Useful Post:

    mruhomau (08-09-2016)

  7. #5
    mruhomau's Avatar
    mruhomau is offline Bright Giants
    Points: 4,197, Level: 43
    Level completed: 65%, Points required for next Level: 53
    Overall activity: 4.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Gallery Achievement!
    Join Date
    Jul 2016
    Location
    Oakville
    Posts
    270
    Points
    4,197
    Level
    43
    Thanks
    72
    Thanked 7x 7 Posts

    Default Re: eyepiece advice for DSO viewing for my humble scope

    thank you Ozman13


    question : based on my understanding here, with a 32.5 magnification, that should be enough for me to spot most common deep sky objects ? and for some of them once spotted, I can use a barlow to keep the apparent field of view but increase magnification?

    can you please give me an example of a deep sky object that would require magnification ? would that be a galaxy ? sorry I'm still very amateur when it comes to sky viewing

  8. #6
    Ozman13's Avatar
    Ozman13 is offline HYPER GIANT
    Points: 29,217, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 20.0%
    Achievements:
    2 Posts Achievement5 Threads Achievement!20 Posts Achievement!365 Days+ Registered Achievement!50 Posts Achievement!
    Join Date
    Jun 2013
    Location
    Hopkinsville Kentucky
    Posts
    8,431
    Points
    29,217
    Level
    100
    Thanks
    170
    Thanked 2,238x 2,011 Posts

    Default Re: eyepiece advice for DSO viewing for my humble scope

    Some of the DSOs are quite small, also magnification will darken the background helping to bring out detail. Very faint small galaxies will benefit this way. Also there are many globs that will allow you to resolve individual stars with higher magnification. Low magnification helps you with spotting them, then if conditions allow, higher magnification will help bring out subtle detail.
    cleary524 likes this.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ACF 8"SCT,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    120, ES 102CF Apo triplet, ES AR102, ST100, ST90, Apex 90mm Mak, ST80, ETX60,
    Oberwerk BT-82XL-ED, 25x100s, 15x70s, 8x56s, Kasai 2.3x40s, Celestron AVX, CG4, SLT, LCM, Obie HD Parallel Bino mount
    Explore Scientific 82 degree and 68 degree EPs, Baader 9mm Ortho, Meade 5000 SWA EP set, many more various EPs, Baader
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    &SkyGlow, FringeKiller, SemiApo filters, Celestron UHC, Meade 4000 Nebular Filter, Kson OIII, DGM NPB and lots of astro stuff.

  9. The Following User Says Thank You to Ozman13 For This Useful Post:

    mruhomau (08-09-2016)

  10. #7
    PhilipLangley's Avatar
    PhilipLangley is offline SUPER GIANT
    Points: 15,459, Level: 85
    Level completed: 74%, Points required for next Level: 91
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!200+ Posts Achievement!
    Join Date
    Jul 2014
    Location
    Western Canada
    Posts
    1,451
    Points
    15,459
    Level
    85
    Thanks
    39
    Thanked 630x 456 Posts

    Default Re: eyepiece advice for DSO viewing for my humble scope

    An all rounder, in terms of DSO viewing, would be that which typically yields an exit pupil in your scope of about 2mm.

    There are many who would opine that an exit pupil = 2mm is to be considered optimal for DSO viewing. This since it yields a useful balance between brightness and resolution. Too much magnification and you get darker, over-pixelated images in the eyepiece.

    Since your scope has a 1.25" focuser and you have already expressed an interest in the waterproof ES 82° eyepieces why not take a boo at the:

    11mm yielding a magnification = 59x, TFOV = 1.390° = 83', exit pupil = 2.2mm

    14mm yielding a magnification = 46x, TFOV = 1.783° = 107', exit pupil = 2.8mm

    My rationale is that you already have a 10mm and 20mm stock eyepiece. Of these, the lower power 20mm is probably the better of the two at the moment. The higher power 10mm is probably yielding a soft, mushy view and might need to be replaced sooner than later.

    So keep, and live with, your 20mm until it is intentionally replaced later and dig in now with a 11mm ES 82° to replace the 10mm. The 11mm gets you nice and close to the suggested 2mm exit pupil, with a much wider TFOV, for DSO viewing.

    Some might then suggest that you rip the lens elements out of the 10mm and use it as a collimation cap.

    These two eyepieces will yield the following TFOVs:

    11mm ES: TFOV = 1.390° = 83'
    20mm stock: TFOV = 1.563° = 94' or about 13% larger than that of the 11mm.

    For all intents and purposes, I doubt that you'll even recognize a 13% increase in the TFOV and as such, you'll probably see the TFOV as about the same. The difference in the AFOV will however be huge.

    Another way of looking at this is to retain both the 10mm and 20mm stock eyepieces in service and pitch your new acquisition about midway in between these. You then choose the 1.25" 14mm ES 82° which would yield a magnification about half way between these and a medium exit pupil = 2.8mm.

    Then in incremental future steps, you first add the 11mm and then, sometime after that, the 20mm. Now you got all three. You keep the stock eyepieces in reserve in case you ever want to sell them together with your scope.

    In either case, you always need to imagine what your your future plans might be.

    And as always, if you possibly can, do try to get out to a star party of some sort and try out any eyepieces offered in your scope. Numbered parameters are nice, but seeing is truly believing. When doing this, just be aware that the set-screws in your focuser have the potential to scratch or mar the security groove of the loaner. And no-one appreciates that...ever! Tread gently when screwing with another's eyepieces....or better yet, have them install the eyepiece into your focuser. That invitation is usually welcomed.

    This dual offering probably muddies the water for you more than it clarifies. Sorry about that eh!
    j.gardavsky and omeek like this.

  11. The Following User Says Thank You to PhilipLangley For This Useful Post:

    mruhomau (08-09-2016)

  12. #8
    Ozman13's Avatar
    Ozman13 is offline HYPER GIANT
    Points: 29,217, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 20.0%
    Achievements:
    2 Posts Achievement5 Threads Achievement!20 Posts Achievement!365 Days+ Registered Achievement!50 Posts Achievement!
    Join Date
    Jun 2013
    Location
    Hopkinsville Kentucky
    Posts
    8,431
    Points
    29,217
    Level
    100
    Thanks
    170
    Thanked 2,238x 2,011 Posts

    Default Re: eyepiece advice for DSO viewing for my humble scope

    Sorry, didn't really answer your question. Yes, 32.5x is good for spotting most DSOs. When using a 2x Barlow, you will keep the eye relief of the EP, double the magnification, and cut the field of view in half.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ACF 8"SCT,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    120, ES 102CF Apo triplet, ES AR102, ST100, ST90, Apex 90mm Mak, ST80, ETX60,
    Oberwerk BT-82XL-ED, 25x100s, 15x70s, 8x56s, Kasai 2.3x40s, Celestron AVX, CG4, SLT, LCM, Obie HD Parallel Bino mount
    Explore Scientific 82 degree and 68 degree EPs, Baader 9mm Ortho, Meade 5000 SWA EP set, many more various EPs, Baader
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    &SkyGlow, FringeKiller, SemiApo filters, Celestron UHC, Meade 4000 Nebular Filter, Kson OIII, DGM NPB and lots of astro stuff.

  13. #9
    mruhomau's Avatar
    mruhomau is offline Bright Giants
    Points: 4,197, Level: 43
    Level completed: 65%, Points required for next Level: 53
    Overall activity: 4.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Gallery Achievement!
    Join Date
    Jul 2016
    Location
    Oakville
    Posts
    270
    Points
    4,197
    Level
    43
    Thanks
    72
    Thanked 7x 7 Posts

    Default Re: eyepiece advice for DSO viewing for my humble scope

    thanks for the background info guys... that helps. I think since I already have a 20mm, I am leaning towards the explore scientific 11 mm. I can use my 20mm to locate and then the 11mm for optimum viewing based on the above exit pupil explanation.

    Also as per my previous notes from previous posts in this Forum, I was also explained the info regarding size of DSO. so If I understood correctly and if I apply it in this scenario, i.e for the 11mm ES 82 eyepiece :

    TFOV = 82 / 59.09 = 1.39 degrees of arc = 83.26 minutes of arc

    When I look at the messier charts ( that was also provided to me on previous posts ), I see that about 65 - 75 % of deep sky objects are smaller than 83.26 minutes of arc. I was thinking of making an average of the sizes as per the chart but I am a bit too lazy to do that now. lol. I just spot checked the chart and I see that 83.26 minutes of arc seems to be accommodating most of those objects

    guys, should I go for the ES 11mm eyepiece ? and use my 20mm to find DSO ?

  14. #10
    mruhomau's Avatar
    mruhomau is offline Bright Giants
    Points: 4,197, Level: 43
    Level completed: 65%, Points required for next Level: 53
    Overall activity: 4.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Gallery Achievement!
    Join Date
    Jul 2016
    Location
    Oakville
    Posts
    270
    Points
    4,197
    Level
    43
    Thanks
    72
    Thanked 7x 7 Posts

    Default Re: eyepiece advice for DSO viewing for my humble scope

    " Sorry, didn't really answer your question. Yes, 32.5x is good for spotting most DSOs. When using a 2x Barlow, you will keep the eye relief of the EP, double the magnification, and cut the field of view in half. "


    thank you Ozman13. I am curious. do you usually notice a difference in brightness or light loss when using a barlow ? e.g a 10mm eyepiece vs a 20mm eyepiece with a 2x barlow . do you usually see any difference between those two setups ?

 

 
Page 1 of 5 123 ... LastLast

Similar Threads

  1. Humble Pie
    By WildWithin in forum Astronomy Digital Cameras Forum
    Replies: 18
    Last Post: 10-25-2015, 07:05 AM
  2. Starter eyepiece advice for a Zenithstar 71mm scope...
    By nialljcampbell in forum Astronomy Beginners Forum
    Replies: 6
    Last Post: 12-28-2014, 07:10 PM
  3. DSLR Deep Sky Imaging: My humble Jupiter
    By Chris220220 in forum Astrophotography Forum
    Replies: 1
    Last Post: 11-15-2012, 03:32 AM
  4. New scope, looking for eyepiece advice
    By odd1 in forum Telescope Eyepieces Forum
    Replies: 12
    Last Post: 12-12-2011, 05:30 AM
  5. let's be humble !
    By Eric Pouhier in forum Amateur Astronomy Forum
    Replies: 34
    Last Post: 02-15-2004, 11:35 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 11:48 AM.