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M-52, NGC-7635, SH2-157, SH2-158, SH2-159, SH2-161, NGC-7510

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Posts Made By: Matt Tarlach

December 31, 2007 02:59 AM Forum: Eyepieces

21/24 Hyperion or 20XW?

Posted By Matt Tarlach

Hi there. I've been halfway out of the hobby for a couple of years and some of the technology looks to have passed me by. I've searched the archive for these eyepieces but come up a little short on info that applies to my particular situation. Hope you all can give me some tips.

Am looking for a new eyepiece to replace my 24.5mm Meade SWA. It gave good service on slower scopes (f7 and slower) but I find the edge performance unsatisfactory on an f5 dob. I'd like to have longer eye relief too, as my astigmatism (in my eyeball, not my primary mirror!) gets ugly at exit pupils of 4-5mm and I prefer to use my eyeglasses for wide field viewing. I tried a friend's 24mm Panoptic and it was much better at the edge of field but not quite enough eye relief.

So, if I want 65+ degree field and ~20mm eye relief in a 20-24mm, 1.25" ep, I think my choices are Hyperion or Pentax XW. I guess there's the Stratus too, but those look similar to the Hyperion and the Baader coatings are supposed to be a little better. The 24mm Hyperion gets so-so reviews on fast scopes, but I can't find much on the 21mm, which is apparently a different design. With the integrated "barlow" might the 21mm Hyperion be a better performer at f5 than the 24mm? Is the 20mm XW going to be much better than the 21mm Hyperion at f5, enough of a difference to be noticeable through the coma in an f5 newt?

Is there something else out there I should be looking at? A 22mm T4 Nagler would fill all my needs and then some, I'm sure, but the price is prohibitive especially since I'd have to upgrade my filters to 2" to get full use out of it.

Thanks!!

Matt

July 24, 2008 10:10 PM Forum: Eyepieces

Best value ~24mm wide for f5?

Posted By Matt Tarlach

Hi there. I used to know more about this stuff but have been halfway out of the hobby for a few years now and out of date, I'm sure. I'm trading my little-used gee-whiz goto scope for a dob, in hopes of rekindling my enthusiasm for the hobby. No doubt the following is a common question but I don't have time to prowl the forums as I used so I hope some folks can take a moment to weigh in and help me out....

What eyepiece of those currently available would you all suggest to meet the following need:

- 1.25" barrel
- 65-70d degree apparent field
- 21-25mm (for ~max true field in 1.25")
- Good performance at f5 - center should be very sharp, edge acceptable. to give you an idea of my personal tastes I have a Meade 4000 24.5mm SWA that I find much too soft at the edge at f5.
- >17mm eye relief as I need to wear my specs at this exit pupil

Interested in two answers - 1) a top value eyepiece that does all of the above, and 2) the very best eyepiece to meet all these needs, in case the wife decides I deserve an early birthday present.

Any help would be much appreciated.

Matt Tarlach