patrick77
member
Reged: 09/15/09
Posts: 45
Loc: Memphis Tn area
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I have been doing allot of reading and learning on this site. I dont see info about the eyepieces used and what quality and power they are when viewing DSO objects like galaxies!!??
I might have missed it but as of now I just dont see much, This site does have allot of info to learn from!!! I have a 10inch Lightbridge and I want to see a galaxy if possible!
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New to this hobby, really enjoy looking at the stars!!
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starrancher
professor emeritus
Reged: 06/09/09
Posts: 620
Loc: Northern Arizona
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Lots of galaxies are possible with a 10 inch scope . The magnification produced by any eyepiece is dictated by the focal length of the scope it is being used in . The selection of the magnification being used is going to be reliant on the particular object being viewed as well as the seeing conditions at the time & if a full view of the object is desired as opposed to a higher power view into a specific region of the object .
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LXD75 AR5
LXD75 SN8
Series 4000 Plossls
Misc. other stuff
Fort Rock , Az .
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JakeSaloranta
sage
Reged: 09/18/08
Posts: 237
Loc: Sisu, Sauna, Sibelius...
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I don't think super quality eyepieces play such a huge importance. I've used cheap (50$) Plössl and Omni eyepieces for a decade now and I'm still pretty happy with them. Sure expensive Naglers have crispy clean images and so forth... but for me the limiting factor is the price. Besides I'm known to be a little forgetful with equipment so loosing a 500$ Nagler would probably give me a heart attack.
Also I think at least some people who write reviews/praises get the eyepieces for a discount or for free. How accurate and honest can this kind of review be? I've written some reviews this way and it feels like I'm expected to write only good things about the product which makes it difficult.
And you should literally be able to spot thousands of galaxies with a 10" telescope with a basic set of eyepieces under dark skies. Make sure you have minimal light pollution. I doubt eyepiece quality will be your limiting factor at spotting a galaxy unless the eyepiece is broken or something similar.
If you're interesting in reading about eyepieces: reviews, basic information... use Google.
/Jake
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PeterSurma
super member
Reged: 08/24/06
Posts: 122
Loc: Heidelberg, Germany
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Most important for galaxies is sky quality, i.e. a really dark site (milkyway easily seen with structured clouds, stars of 5-6mag pretty easy to see).
Second, don't stay at low power only. Go to higher magnifications. Details might come out the more you enlarge the image.
Third, expensive + good EPs (with large field of view + good correction) are nice to have of course. However you should first try the stuff you have and check what you can get. Buying new stuff is good for dealers, but not necessarily good for you. If you have a f/5, f/6 scope or slower (higher f-number) don't worry about Naglers and such too much. If you are in the f/4 range, Nagler quality gets more important for observing (because fast scopes have optical errors that get more well-corrected by hi-quality EPs).
Get a set (I'd say 4 or max 5) of reasonable EPs stepped by a factor of 1.5....1.6 in focal length( e.g. 30mm, 20mm, 13mm, 9mm, 6mm). The maximal and minimal f of EPs is calculated by
f_ep_max = f-number of scope x 7mm
f_ep_min = f-number of scope x 1mm
(actually you might go down as far as x 0.5mm in excellent seeing conditions). So for your f/5 lightbridge this means: get EPs in the range 35mm down to 5mm.
Calculating magnification goes this way:
magn = f of scope / f of EP
Having EPs with large field of view (fov) is generally nice. It is especially helpful at the large EP-f end, i.e. at low magnification. Large FOV of the EP means large FOV at the sky. So if you have large objects (Northamerica Nebula, Cirrus, California, other overviews) you are happy to have enough field, so that the object can be seen as a whole. Also, for searching large fov is good, because you have more characteristic stars in your fov for star hopping. You need less hops until you find the objects.
Insofar Naglers (fow = 82° / magnification) (or even Ethos fov = 100°/magnification) are excellent. But you can do without them , too, of course... :-)
That's basically all you need to know. :-)
Good luck !
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For illustration: here is my set of EPs used on a 20" f/4 scope:
f [mm] 31 20 13 9 5 2.5
AP [mm] 7.8 5 3.3 2.3 1.3 0.65
Magn 65x 100x 155x 225x 400x 800x
Field 1.25° 0.8° 0.5° 0.36° 0.2° 0.1°
Limit [mag] 15.8 16.5 16.9 17.1 17.0 16.9
Same set of EPs on my 5" f/5 finder:
AP [mm] 6.2 4.0 2.6 1.8 1.0 0.5
Magn 24x 38x 58x 83x 150x 300x
field 3.4° 2.2° 1.4° 1.0° 0.55° 0.27°
Limit [mag] 13.6 14.1 14.5 14.7 14.9 14.9
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Peter
Web: http://www.eyes4skies.de/home_EnglishVersion.htm
Scopes: From 3inch photographic APO to 20inch f/4 Dob
Edited by PeterSurma (10/16/09 06:09 AM)
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droid
rocketman
Reged: 08/29/04
Posts: 4047
Loc: ohio
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On the other side of the coin.......I ue an 4 inch f/8 refractor and wide field ,2 inch , super wide angle plossls deliver almost rich field like views that make finding M51 a piece of cake.
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12 inch Truss Reflector "John"
102mm Celestron C102HD
Tasco 7TE5 60mm Classic
Tasco 9TE5 60mm Classic
Celestron Ultima 2000 SCT
Remains of an 8 inch dob
Celestron Comet catcher(orange tube)
1960 Edscorp Space Conquerer 6inch f/8
10x50 Bushnell Binoculars.
11T 4.5 inch Tasco reflector Lunograsso?
60mm Telescope Club
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Hrundi
Pooh-Bah
Reged: 02/06/08
Posts: 1247
Loc: Estonia
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Considering bundled EP's nowadays are plössls, there's really not much of a chance of getting an eyepiece bad enough for it to matter much.
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JayKSC
scholastic sledgehammer
Reged: 01/01/05
Posts: 985
Loc: Florida
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To second the great comments others have offered, I don't think that the particular eyepiece plays a tremendous role in whether you see a given object or not (assuming that the eyepiece isn't made entirely of plastic from a department-store scope!).
That said, I've found that eyepieces do play some role in seeing detail and in how much a very dim object might contrast against the background sky. Generally, I've found high quality true orthoscopic eyepieces to yield excellent contrast and sharpness, usually a bit more than plossls. The effect is minimal, but I notice it. I also notice that premium eyepieces tend to also show slight improvement over inexpensive plossls. The key word I'll emphasize is slight. For the most part, aperture and sky conditions (as others have emphasized) play more a role in what you see.
- Jay
South Florida
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Refractor manic. 
My Sketches
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Jim Curry
sage
Reged: 10/29/07
Posts: 434
Loc: Maine
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>I might have missed it but as of now I just dont see much,<
Patrick:
From this statement I'm not certain if you're seeing galaxies and not seeing detail or you just can't find them so I'll try to answer both, briefly.
If you're locating galaxies and not seeing much detail it could be because your expectations are a little high after looking at astrophoto's. The detail will be noticed on the brighter galaxies with a fair amount of study and experience. If you can't locate them, get a star atlas.
As far as eyepieces are concerned, you didn't state what you have. A suite of 3, low, medium and high power eyepieces, say 30-40x, 80-100x and 130-150x will give you a good selection to gain experience. With a push-to scope your comfort level may be with wide field ep's so the object stays in the field of view longer. With experience you may decide to get higher x ep's (shorter focal lengths) and try different manufacturer's. Don't feel the need to toss a lot of $ at it without gaining some experience. Keep reading and asking questions.
Jim
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Vixen 140 refractor
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patrick77
member
Reged: 09/15/09
Posts: 45
Loc: Memphis Tn area
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Sorry for the lack of info! I used to own an ETX 125ec so I have eyepieces that Im not sure are good for this scope! What I have is 2 smartastronomy plossl eyepieces a 12.5 and a 25mm, then I have a meade 2 inch 26mm QX and a celestron 8-24 Zoom 93230. I also have color filters and a 3x and a 2x barlow I have not had a real good chance to use my new 10 LB but I hope to soon! I just dont know the correct eyepieces to use?? thanks for all the help!!
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New to this hobby, really enjoy looking at the stars!!
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starrancher
professor emeritus
Reged: 06/09/09
Posts: 620
Loc: Northern Arizona
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Patrick ; Your scope has a 1270mm focal length . So to do the math , a 25mm ocular on that scope is 1270%25= 50.8 . So say 51x magnification . The 12.5mm will yield about 102x . (101.6) etc . Plossls are good eyepieces & will work just fine in the LightBridge . Of course you know what the Barlows are going to do . & with the zoom you've got a pretty good range of magnifications going . You are really only lacking a good low power wide field ocular . If you like the 26mm Meade QX & the way it performs in that scope , you might give the 36mm QX a try as that will yield a magnification of 35x for you & a true field of view of about 2 degrees . You should be able to get most of the largest DSOs' in that field of view . I.E. Most of the Andromeda galaxy with both it's companions . What a view that should be in a 10 inch scope .
Hope this helps
Dave
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LXD75 AR5
LXD75 SN8
Series 4000 Plossls
Misc. other stuff
Fort Rock , Az .
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patrick77
member
Reged: 09/15/09
Posts: 45
Loc: Memphis Tn area
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Quote:
Patrick ; Your scope has a 1270mm focal length . So to do the math , a 25mm ocular on that scope is 1270%25= 50.8 . So say 51x magnification . The 12.5mm will yield about 102x . (101.6) etc . Plossls are good eyepieces & will work just fine in the LightBridge . Of course you know what the Barlows are going to do . & with the zoom you've got a pretty good range of magnifications going . You are really only lacking a good low power wide field ocular . If you like the 26mm Meade QX & the way it performs in that scope , you might give the 36mm QX a try as that will yield a magnification of 35x for you & a true field of view of about 2 degrees . You should be able to get most of the largest DSOs' in that field of view . I.E. Most of the Andromeda galaxy with both it's companions . What a view that should be in a 10 inch scope .
Hope this helps
Dave
Yes that does help!! I do know how to figure out my eyepiece mag and I will look into the 36mm QX Thanks.. I live in an area just outside Memphis TN and the light polution is pretty bad! There was a CN member that used to live in my same area that had his own web site. He was able to see some great stuff so I hope there is some hope for me, his scope was a big one but I still hope for the best!! He moved to New Mexico were the sky is real clear!!! thanks again!!!
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New to this hobby, really enjoy looking at the stars!!
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scopethis
professor emeritus
Reged: 05/30/08
Posts: 638
Loc: Kingman, Ks
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Galaxies are finicky creatures. On some you can really push the power and see some fine detail. Others will begin to fade away with increased power. Sometimes the best view is with very low power. There just ain't no one size (eyepiece) fits all. Plossls are good eyepieces to observe galaxies with. And a decent low power 30-40mm wide field EP is great for looking at galaxy duos and triplets.
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wfj
sage
Reged: 01/10/08
Posts: 260
Loc: California, Santa Cruz County
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The joy of well corrected wide field EP plus coma corrector is to have an enormous FOV with which to find a object within, where everything is sharp, so if something has the "non star" shape, you can pick it out immediately. Helps to make the telescope disappear, such that you feel suspended in space. You can work at a higher power, without having to shift back and forth between EPs to reacquire the object.
Without the better correction for coma and f/ cone angle due a fast newt, a wide field EP's FOV contains mostly "non star like" objects due to aberrations distorting stars. Newts are great for wide field anyways - but when you have SCT's / MCT's, they are difficult to get wide field views out of - so the need for such highly corrected EPs isn't the same (field curvature and a focal reducer that corrects it is more important) - stars are stars, well corrected EPs or not (the wide field still helps either way).
As to detailing a galaxy fitting the seeing of the moment, these attributes aren't necessary the ones that matter. Since you'll likely center the object, a sharp, high contrast EP with good coatings that doesn't dim a DSO is likely what you desire. Ortho's are perfect - look no further in this case.
Beyond this, the 'Eyepiece' forum goes into greater detail on the subject. I have been surprised on the EP that works best for various objects - not always predictable.
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Dean Norris
sage
Reged: 11/05/08
Posts: 431
Loc: Santa Cruz, Ca
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In regards to selecting a low power eyepiece a person should use -what helped me with viewing deep sky objects was getting a low power eyepiece that has an exit pupil near 5mm. I purchased a 32mm Televue plossl that gives me a 5.3 mm exit pupil. A person of 50 years or older, has a pupil that will dilate to 5mm on average. This is near the range to 5,3 exit pupil of the 32mm ep. That makes this a good ep for me to first locate objects with. I also have a 40mm TV ep that I bought years ago and found that the 32mm works better for me and deep sky objects actually appear a little brighter with the 32 mm. The 40mm has a 6.6 mm exit pupil. So if my eye only dilates to 5mm I'm losing light since the image is bigger than my eye dilates to. You determine the exit pupil by dividing the size of the ep by the F number of the telescope. My telescope is a F/6, the eyepiece is 32mm. 32mm divided by 6 = 5.3 exit pupil. When I first used the 32mm ep I was able to locate some objects on the first evening that I had no luck with the 40 mm. I no longer use the 40mm but will keep it for now, maybe using on a different scope in the future. I did read that a 20 year old person's eye does dilate to a larger size ( around 7mm ). So age does play a role on selecting the best low power ep a person should use. I hope this is helpful.
Dean
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1971 10" Cave Newtonian F/6
MoonLite CR Focuser Telrad Finder 8x50 finder
TV 40mm, 32, 20, 7.4, Meade 6mm, UO 5mm, Meade 2x Barlow
7x50 Binoculars
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patrick77
member
Reged: 09/15/09
Posts: 45
Loc: Memphis Tn area
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I finally got to use my scope last night!! The dew point was high so Im not sure how that affected my viewing! I did have a problem with my 2 inch eyepiece and focusing it, I had to pull it out of the scope a bit to be able to focus it. Is that normal???
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New to this hobby, really enjoy looking at the stars!!
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arpruss
scholastic sledgehammer
Reged: 05/23/08
Posts: 858
Loc: Waco, TX
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Try using the collimation screws to push the mirror as far back as you can (while still being able to collimate), and see if that helps. Alternately, get an extension tube for the focuser.
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Coulter Odyssey 13.1" split-tube
Coulter Odyssey 8"
Home-made 7.8" F/4 dobsonian travel scope
Home-made 68mm F/5.3 achro (typically used as finder on 13.1")
Skymaster 15x70
BPTs4 8x30
32mm Plossl, 30mm Rini, 27mm Kellner, 13mm Hyperion, 6mm TMB/BO Planetary, Owl 2X Barlow
Palm TX with AstroInfo and RescoViewer
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JayinUT
I'm not Sleepy
Reged: 09/19/08
Posts: 953
Loc: Utah
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As others have stated:
1. Dark Sky, Dark Sky, Dark Sky brings the best views.
2. Slow down, slow down, slow down and observe. It takes the eye time to learn how to see detail and most often people fly by a galaxy and don't take the time to learn how to see the details in it. Not saying you are Patrick, but just an observation.
3. Practice by observing when you can. The more you observe the more you train your eye how to identify these items.
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Jay in Utah
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Location: Lat: 40.514N Long: -112.032W
Mortal as I am, I know that I am born for a day. But when I follow at my pleasure the serried multitude of the stars in their circular course, my feet no longer touch the earth.
— Ptolemy, c.150 AD
My Blog
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Feidb
super member
Reged: 10/09/09
Posts: 127
Loc: Nevada
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To me, the eyepiece is as important as the main optics. However, most of the faint fuzzies I go for are very small, so I chose the cheap route and use Orion Q-70's. Lousy edge, but the center is great. I have got used to the coma at the edges of the field so that I can tell whether I'm skimming by a DSO or just a blurry star. I just can't see paying half the price of my scope for a flat field to the edge.
Then again, the sky conditions are very important. If the night has any glow to it or the transparency is an issue, it will blot out those faint fuzzies in a heartbeat.
For such objects, you don't even have to have an exquisite mirror (or lens) as being extended objects, they are more forgiving.
For galaxies, of which I've seen over 800 now, I start with the 26mm Q-70 and if I want to get up close, I add my Parks 2" Barlow. That gives me either 70X or 140X. Sometimes the 140X brings out details, sometimes it just washes things out.
The fact is that I identified over 100 of those galaxies with an 8" f/9.44 so a 10" would work just fine. I think your biggest challenge is looking in the right spot, recognizing something is there, and sky conditions. You don't need to break the bank on a premium eyepiece just to see galaxies. I saw plenty of them in a .965" 20mm Kellner from my old Sears refractor!
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Present gear:
16" Meade LightBridge
Meade 50mm straight through-finder
Lumicon green laser pointer
Orion Q-70 26mm, 32mm, and 38mm
Parks 2X 2" Barlow
Hyperion 17mm, 8mm
1 1/4" 18mm Russell Optics Bertele
1 1/4" 12.5mm and 6mm Coulter Optical Orthoscopics
1 1/4" X 2" 32mm Edmund Scientific war surplus Erfle
Tirion star atlas (white stars, black background) hand-laminated
Megastar
And a partridge in a pear tree
To nudge or not to nudge, that is the question
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patrick77
member
Reged: 09/15/09
Posts: 45
Loc: Memphis Tn area
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Quote:
As others have stated:
1. Dark Sky, Dark Sky, Dark Sky brings the best views.
2. Slow down, slow down, slow down and observe. It takes the eye time to learn how to see detail and most often people fly by a galaxy and don't take the time to learn how to see the details in it. Not saying you are Patrick, but just an observation.
3. Practice by observing when you can. The more you observe the more you train your eye how to identify these items.
Your right I do need to slow down! My other problem is the lack of dark sky!!! thanks
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New to this hobby, really enjoy looking at the stars!!
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ebusinesstutor
sage
Reged: 07/01/09
Posts: 468
Loc: Nanaimo, BC, Canada
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Quote:
As others have stated:
1. Dark Sky, Dark Sky, Dark Sky brings the best views.
2. Slow down, slow down, slow down and observe. It takes the eye time to learn how to see detail and most often people fly by a galaxy and don't take the time to learn how to see the details in it. Not saying you are Patrick, but just an observation.
3. Practice by observing when you can. The more you observe the more you train your eye how to identify these items.
Very useful tips, Jay. As a beginner, I am noticing more detail now than just a few months ago in my viewing even though the scope and eyepieces are the same.
And finding DSOs is getting a little easier as well. Still a long way to go, but nice to see my skills and viewing slowly improving.
Practice definitely helps!
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Garland Coulson
Orion XT8i Dob & Celestron 80 ED on a Vixen Porta Mount Mini
Baader Hyperion 8-24mm Click Zoom & Siebert Observatory 36mm
Siebert Black Knight Binoviewers
SkyWatcher Observing Chair
Celestron Skymaster 15x70mm binos
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