wide field eyepiece for 16" f/4.9?

Started by Mike Ratcliff, 05/24/2004 04:33PM
Posted 05/24/2004 04:33PM Opening Post
I'm wondering what eyepiece to get for wide field viewing. I don't want to spend $500 or so for the big 26mm or 31mm Naglers. But I tried the inexpensive BW Optik 30mm 80 degree widefield, and the aberations were too much for f4.9. So yeah I want it both ways, good views and reasonable price.

I've got a 17mm Nagler Type4 for medium magnification but that only covers a 0.7 deg field. Telescope is 16" f4.9 dob Newt with a 3.1 inch secondary.

I know that an exit pupil greater than 5 to 6 mm will be too big for my 49 year old eyes and some light is lost. Is it OK to go beyond 6 mm exit pupil anyway for the field of view? If so, how far beyond 6mm before the secondary shadow is a problem? What is your recommendation?


Thanks much,
Mike Ratcliff
Posted 05/24/2004 06:10PM #1
There are other options. At F4.9, your scope will be quite particular about which eyepieces you choose. I am not into the big money eyepieces, I have tried a few of the less expensive ones.

Currently I am using an old TV 32mm Widefield, these were made prior to the Panoptics and have a similar FOV. I had a chance to compare 35mm Panoptic with my 32mm Widefield in my F4.1 Newtonian and I thought the Widefield stood up well considering the cost and weight difference. Compared to the BW-Optik 30mm, it is far sharper through out the FOV.

They are somewhat rare but show up every so often on Astromart for around $150 or so.

The Meade Super-WideFields were apparently direct copies of the TV eyepieces, not sure how they Meade compares but lots of folks like em.

jon
Posted 05/24/2004 07:02PM #2
Mike,
Another option for you to consider is purchasing the low-cost 2" 2x barlow from Owl services for $59.00 and using it with the BW Optik 2" eyepiece. It cleans-up the edges of the Optik as well as the TAL 24mm 2" widefield eyepiece in my 16" F4.5 dob and the combo costs far less than premium widefield 2" eyepieces.
Posted 05/24/2004 07:15PM #3
The Meade SuperWide 32 is pretty good at f/4.9 new retail price is $240, I have not tried the 40mm at $300.
TV 35mm Panoptic at $365 is very good. They do come up here used all the time.
Siebert Optics Observation series 2" EPs 34,36,40mm work pretty well at $200.
Hope this helps.
Floyd

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