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Old 21-07-2017, 09:49 PM
kramenyak77 (Kayne)
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Eyepieces

So tonight I was able to get a fairly clear view of Jupiter, but what I saw through my eyepiece was way too small. I'm using the eyepiece that came with my 925 (the eyepiece is 23mm) and am using it on the diagonal it came with, but what I'm seeing isn't much bigger than what I see with my naked eye. I was reading that perhaps I should get something around 14mm. Would that make what I see a bit larger? Go gentle on my I'm a noob.
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Old 21-07-2017, 10:08 PM
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Nebulous (Chris)
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Hi Mark, from a fellow Noob. Well, a three months Noob anyway...

Yes, that should make the view bigger. But the mathematics of this hobby seem to be able to play tricks on you sometimes..

My scopes came with basic quality 10mm and 25mm lenses, which both seem to work pretty well and "as advertised". Slip the 10mm in and everything gets bigger.

So I lashed out on an (allegedly) good 6mm and also a 40mm, hoping to get great close-ups with the 6mm and nice wide views with the 40mm (easier to navigate when you can see more sky). And mostly it works that way.

However, sometimes the results aren't as good as you'd hope for. Bigger isn't always better. Due to a variety of factors (i.e. I don't really know what they all are... ) sometimes the clearest results were obtained with the medium range lenses. I guess it's a combination of the optics of the scope, the 'seeing' conditions in the sky, and even the quality of your own eyes (poor in my case) plus the ever-present astronomy gremlins, but sometimes the numbers don't quite deliver eveything that you hoped for.

All the best with it.

Cheers,

Chris
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Old 21-07-2017, 10:11 PM
m11 (Mel)
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Hi Mark,

I assume you have a Celestron 9.25 SCT? Google search shows:

2350 mm focal length (f/10)

2350mm/23mm=102x magnification view (focal length divided by the eyepiece focal length)

You probably want something that gives around ~130x - 150x as most nights you will be limited by the seeing conditions. A barlow will be useful as well to double your eyepiece set. I find it not that often I can push beyond 220x due to the seeing conditions.

Also since you have a SCT, you will need more time to cool it down as it is sealed to improve viewing.

Its a slippery slope when it comes to eyepieces, you can spend a lot . This becomes apparent with wider degrees of view of eyepieces.

Hope it helps.

Regards,

Mel

Last edited by m11; 21-07-2017 at 11:16 PM.
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Old 22-07-2017, 09:18 AM
Wavytone
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Hi Mark,

14mm is a good mid-range choice with your SCT. 9mm (260X) is the practical limit for the rare nights of excellent seeing.

At the low end your scope could also fill a big 2" low-power eyepiece, such as a 38mm 70 degree FoV ProStar (40X), or similar. Something like that is excellent on open clusters which will sparkle like diamonds scattered on velvet.

At f/10 budget eyepieces are usually fine, no need for a box full of Naglers.
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Old 22-07-2017, 11:38 AM
kramenyak77 (Kayne)
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Smile

My current one is a luminos by Celestron. 23mm with 82°
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Old 28-07-2017, 11:07 AM
brian nordstrom (As avatar)
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I too have a C9.25 and find it an awesome scope that takes silly high magnifications ( 500x plus = 3mm , 4mm and 5mm TV Radian ) on those few great nights but I find that 100-200x is about average for most nights .

I have the 32mm Celestron Axiom , the older version of the Luminos and find it a very good eyepiece , anyway as said I would look at the very fine and well priced ' Superview' 15mm from Andrews giving 156x as these are the best bang for buck going today bar none !! lots of people use and love these and to tell the truth I could not see a difference when compared to my 15mm TV Panoptic in my C9.25 at 10x the price scary but true . ( slightly worse in my f6 scope but still good ) .
Showing that you don't have to spend a fortune to get good views .

Then as I could afford it grab one of those sweet Long Perng planetary eyepieces from Andrews in the 10mm size giving 235x for high power .

You will find these 2 eyepieces are under $100 for both and perform great in the f10 focal ratio of SCT scopes .

Brian.

Last edited by brian nordstrom; 28-07-2017 at 11:18 AM.
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Old 28-07-2017, 12:24 PM
kramenyak77 (Kayne)
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Thank you Brian that's very helpful.
It appears Andrews is out of the superview lenses but they do have the 10mm LP.
What about zoom lenses. Should I get one? Say 7-21mm or 8-24mm? Or stick with individual lenses?
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Old 28-07-2017, 12:44 PM
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AstralTraveller (David)
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For quality higher-power views where wide field of view is unimportant orthoscopics are a fine performer. They tend to be a bit short on eye relief (though not as short as plossls) but at the focal lengths you will need they aren't too bad. They work on the less-glass-is-best principle: less glass and fewer air/glass surfaces = less scatter and better contrast. In the old days with old lens coatings this was a very important consideration. Better coatings have reduced, but not eliminated, the importance of these considerations. My 9mm Nagler is a damn fine ep but my 9mm UO Ortho is perceptibly sharper with more contrast. I use them for different purposes.
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Old 28-07-2017, 01:14 PM
kramenyak77 (Kayne)
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Is a nagler worth the $$$ ?
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Old 28-07-2017, 01:32 PM
brian nordstrom (As avatar)
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No , but if it is for you then Yes as its a personal thing , I have at least 30 TV's all got 2nd hand over 12 years from IIS classifieds as there is no way I would buy them new . .

Personally I would stay away from the zoom , it would only be useful in the lower power 18-24mm settings in your scope as the rest would be getting into silly high powers so why have them , better stick with your 23mm and grab say a SV 32-40mm for low power , the 9mm LP for high and 15mm SV for medium/high .

Try Bintel I think they have the 15mm SV's in their ' eyepiece ' section under ' Standard eyepieces ' . Did you look in Andrews page under GSO > Accessories > Superview , they state ' Plenty in stock ' except the 50mm ???

Brian.
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Originally Posted by kramenyak77 View Post
Is a nagler worth the $$$ ?

Last edited by brian nordstrom; 28-07-2017 at 11:54 PM.
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Old 28-07-2017, 05:04 PM
noeyedeer (Matt)
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also you can use stellarium and it's eyepiece projection to see how a certain ep will look in your scope if you know it's field of view and things. it's a handy thing good luck
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Old 29-07-2017, 12:32 AM
brian nordstrom (As avatar)
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thanks brother .
Brian.
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Originally Posted by noeyedeer View Post
also you can use stellarium and it's eyepiece projection to see how a certain ep will look in your scope if you know it's field of view and things. it's a handy thing good luck
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Old 29-07-2017, 08:34 PM
kramenyak77 (Kayne)
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Ok that's great thank you!
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