eyepiece recommendations for c11

[icytailmark (Mark)]

hi guys im looking at buying a c11 with a losmandy g11 sometime this year and im wondering if the eyepieces i currently have will work fine in a c11.

i currently have:

Pentax XW 7mm
TV nagler 13mm
TV nagler 20mm
25mm possel

[astro744]

I believe the standard C11 comes with a 1.25" visual back and 1.25" star diagonal. You will have to upgrade to a 2" visual back and diagonal if you want to use the 2" eyepieces. Each eyepiece that you have will work fine given the right size diagonal.

However, your lowest power is 112x with the 25mm Plossl giving 0.43deg true field with a 2.5mm exit pupil. The 20mm Nagler will give you 140x and 0.56deg true field with a 2.0mm exit pupil.

May I suggest a low power eyepiece that will give you maximum true field. Given the current Tele Vue sale I would recommend the 41mm Panoptic giving you 68x and 0.94deg true field with a 4.1mm exit pupil. An alternative would be the 55mm Plossl giving 51x and 0.94deg true field with a 5.5mm exit pupil.

Note if you stay with the 1.25" visual back and diagonal then look at either the 24mm Panoptic, 32mm Plossl or 40mm Plossl all giving you the same true field (0.55deg) at different powers and exit pupils. You can add the f6.3 reducer/corrector and use your 1.25" eyepieces and your true field will stretch to 0.89deg with the 24/32 or 40 mentioned above. The f6.3 reducer/corrector is not suitable for 2" eyepieces as vignetting and inability to focus can occur.

[icytailmark (Mark)]

im only buying a c11 OTA by itself. Will i still get all the extras you get in a ota/mount package?

[astro744]

Originally Posted by icytailmark

im only buying a c11 OTA by itself. Will i still get all the extras you get in a ota/mount package?

Not sure. Talk to your dealer about what comes with the OTA. I should have mentioned in my previous post that if you want to stay with Nagler eyepieces then the 31mm Nagler will give close to the maximum field and will be a nice match with the 20 and 13mm Nagler eyepieces you already have. You'll get 90x and 0.86deg true field with a 3.1mm exit pupil using the 31mm Nagler.

[icytailmark (Mark)]

thank you for your help

[Rigel003 (Graeme)]

I use a 19mm panoptic and 14 and 10.5 Pentax XLs with my C11. The atmosphere is very rarely steady enough for my 7m Pentax to be useful.

At the widefield end I'd suggest 35 Pan or 31 nagler.