VX12 f4 coma corrector

[C6rrules]

Best advice please , she’s f4 , not a drastic problem for deep sky . I know that OO Newts can be odd sometimes . My old 200 f6 would focus with a 13mm Nagler unless it was well up the focuser . Same oddity with binoviewers.

Looking at coma , any advice would be great , 

clear skies, Nick aka( cotterless45)

[Louis D]

Your best budget bet for visual is a GSO coma corrector that is sold under numerous brands around the world.  I have two, each with a 25mm spacer ring added between the optical section and the eyepiece holder for best correction with my eyepieces that focus near their shoulders.  They're really good except at high powers when the spherical aberration they introduce degrades the view.  I remove it at high powers as a result.  I've found they require 11mm of additional in-focus as I have them configured.

[Space Hopper]

When i had my old OO VX12 F4 Nick, the Televues i had seemed so well corrected, i found coma to not really be an issue.

(I used a 31 Nagler, 24 & 19 Pans and 13 Naglers)

I seem to remember at one point i tried out a Paracorr, but found it  unnecessary. Maybe my eyes are not sensitive to notice it.

Amazed you got binoviewers to focus in an OO newt.....?

 

 

Edited December 3, 2023 by Space Hopper

[John]

One of the characteristics of the OO newtonians that I've owned (3 of them) is that the focal point was well outside the telescope tube. A basic 50mm extension tube is usually supplied with the scope to enable most eyepieces to reach focus. 

 

[Louis D]

Are these OO Newts intended for imaging?  Otherwise, why suffer the consequences of a large enough secondary to illuminate a focus point well outside the tube?

[Space Hopper]

Good question.

[lunator]

I've never had an issue with focus in my OO F6 newt. It has some coma with the 2" eyepiece but as I use that as a 'finder' more than for anything else I don't worry about it. 

Hopefully you can get the best solution Nick.

Cheers

Ian

[John]

10 hours ago, Louis D said:

Are these OO Newts intended for imaging?  Otherwise, why suffer the consequences of a large enough secondary to illuminate a focus point well outside the tube?

OO use smaller diameter tubes than Skywatcher and GSO. My OO 12 inch F/5.3 had a secondary of 63mm diameter so 21% of the primary diameter. Quite modest.

Edited December 3, 2023 by John