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Eyepieces for an 8" f/10?

Started by astroboy314, 12/20/2002 03:33AM
Posted 12/20/2002 03:47AM #1
Hello, I have a Celestron C8 and am ready to upgrade my eyepieces. I am looking to eventually buy two or three premium eps along with a 2x Barlow or Powermate. While I have done my share of observing, I most certainly do not consider myself an expert and have limited experience with premium eps.

My thoughts on my final set of eps are all Panoptics... the 35mm, the 22mm and the 15mm. I've already upgraded my diagonal to a 2", so that's not a concern. I will keep my 32mm SuperPlossl until I can afford the 35mm, but I just sold my 20mm SuperPlossl and am looking to replace it pretty quick. My main question is whether to get the 22mm and the 15mm, or just go inbetween and get the 19mm Panoptic instead (and save some money in the end). Does anyone have any advice on the 19mm vs the 22mm? How easy is it to use a 1.25" Barlow on a 22mm, with its 2"/1.25" format?

So does anyone have any other ep combinations to recommend on a C8 f/10 SCT? Keep in mind that in the end I'll want at most three quality eps, and that the 35mm Panoptic is the highest price I want to go (i.e. no Nagler 31mm... I'd rather get a 35mmm Pan and a 22mm Pan for the same price). Also keep in mind that someday in the future I want to upgrade to a C9.25, and that I have plans to build a 10" f/6 Dob.

I've really rambled on now... Any advice will be greatly appreciated. Thanks!
Posted 12/20/2002 10:21AM #2
I (and most viewers through my scope) have been very happy with the following eyepieces in an F/10 8" SCT. Your mileage may vary, of course, based on your subjective leanings and eye relief requirements.

Nagler 26 ( superceded the Panoptic 35 I was using for the 1 degree+ FOV ). You can get M81/82 or the double cluster in the FOV.

Nagler 17 ( consider Siebert Ultra/Ultra Pluses in this range.. the Siebert UltraPlus 17.5mm (actually tuned for fast FLs), with a Panoptic FOV, is very near the image quality of the Nagler, imo ). Wonderful for most Nebulae/Planets.

Pentax 14mmXL ( used infrequently, but nice on Planets/ Globulars when one wants a little bigger image than the 17 ).

Nagler 9. Used less often, mostly for planets and brighter DSOs in moderately good seeing.

On very rare, good seeing nights, I also reach for the 0.965 Pentax 7mm ortho for planets/globulars/binaries.

Note that this setup requires a 2" diagonal and probably something like Ray's Brackets (for Nexstar 8) to clear the base and balance properly. This is also a more expensive setup than the Panoptics, which in turn is more expensive than the Sieberts, who's line I'm growing increasingly fond of.


Posted 12/21/2002 06:38AM #3
Hi David,

You have received many good suggestions. I have the Nexstar 8, f/10, and have some premium EPs, so I'll just throw in my two cents worth. Bob Black opens an interesting point about the Barlow. I have a TV 2" Big Barlow that I first got hoping to avoid the need for so many EPs. I got away from using it, because I didn't like having to switch it in-and-out all the time. I now have a full range of EPs, mostly Naglers or Panoptics, including the TV 3-6 mm zoom EP that I use on my TV 85mm. As I have gotten more experienced with these scopes and EPs, I find myself using the Barlow again more and more. I do not find much degredation in the view, and I like to keep the FOV, clarity, and contrast of the Naglers, rather than switching to a lower FL EP. Anyway, the Barlow decision is a big one!

For my N8, if I had to choose three EPs to use with a Barlow, I would keep my TV 55mm Plossl, TV 26mm Nagler, and TV 17mm Nagler. This would give me FLs of 22.5mm, 13mm, and 8.5mm with the Barlow. I am not a big fan of the 35mm Panoptic (but am probably in the minority). For the N8/C8 I really like the 55mm Plossl for its FOV.

John R.