C9.25 + 27mm Pano

matt · #1 02-10-2006, 05:11 PM

I've been offered a 27mm Panoptic at a good price, but am wondering if it will work well with my 9.25 SCT?

My 9.25 has a 1.25" visual back, which means I'll have to use the 2" 27mm Pano in a diagonal with an adaptor.

Does using a 2" eyepiece with a scope with a 1.25" visual back present any probs with vignetting, kidneybeaning etc???

Will the scope deliver enough light to the eyepiece to fully enjoy a 2" piece of glass?

Thanks for your help

Striker (Tony) · #2 02-10-2006, 05:29 PM

Cant give you the precise information Matt but I would say you would have to start looking into 35-40mm eyepieces before you start to have any problems.

I had a 31mm Nagler on 10" Meade LX200 with no problems.

Oh the 1 1/4 visual back...boy thats small.

matt · #3 02-10-2006, 05:51 PM

Thanks Tony

Does anyone know if it's possible to replace the 1.25" visual back on a 9.25 with a 2"???

Dennis · #4 02-10-2006, 06:00 PM

Matt

I purchased an SCT to 2" back from Bintel. Basically, it is a simple tube with an SCT thread on one end and a 2" opening with grub screws the other end. However, you would then need a 2" diagonal?

Cheers

Dennis

PS Have a look at "Telescope Accessories" Page 6 on the Bintel site https://www.bintelshop.com.au/welcome.htm for the Orion 2" Visual Back for SCT at $39.00 (3rd row, last column)

matt · #5 02-10-2006, 06:07 PM

Thanks Dennis

So does that mean our 9.25s have a native 2" aperture?

Is that simply an adaptor that Bintel sells?

Striker (Tony) · #6 02-10-2006, 06:09 PM

Dont Peterson make one for celestron.....??????

http://www.petersonengineering.com/SkyDiv/EO.htm

Dennis · #7 02-10-2006, 06:12 PM

Hi Matt

I don't think the hole at the end of the 9 1/4 is a full 2" (50.8mm), but I believe that this should not be a problem for 2" eyepieces with focal lengths of less that say, 35mm? That is, no vignetting effect. However, I'm guessing here so maybe someone who knows more definitely can chip in?

Yes - it's a simple tube with a couple of grub screws. I understand Lumicon offer a similar adapter but with the internal copper ring and a grub screw instead.

Cheers

Dennis

ausastronomer (John Bambury) · #8 02-10-2006, 07:28 PM

Matt,

You're limited by the diameter of the baffle tube in the C9.25 when attaching the 2" visual back. I can tell you that Gary Kopff uses a 35mm Panoptic with his C8 without any vignetting issues, so the 27mm Panoptic with the C9.25 will be fine.

CS-John B