Issue with F5 Coma Corrector for Newtonian Telescope

[cyberblitz]

Equipment used:


10" 1200mm Skywatcher Newtonian Telescope
Nikon 7100 DSLR
Skywatcher F5 Coma Corrector


I have a problem when adding the Skywatcher F5 Coma Corrector for the Newtonian Telescope. The focuser on the scope, with camera without the corrector, is barley moved from its home position. With Coma Corrector added, Focusing requires me to move the camera closer to the Secondary mirror which I can't do, as the focuser reaches its inner limits.

Has anyone else had problems like this, and are there any solutions anyone can suggest I can try???

Thanks...

[peter_4059]

This is a common problem with Newts designed for visual. The easy answer is move the primary mirror closer to the secondary with longer collimation bolts/springs. The other option is to shorten the OTA tube.

[rustigsmed]

Hi David,

Does your SW telescope focuser allow the 1.25" eyepiece holder to be removed? it does on my dob (12" f5) and doesn't require the mirror to be moved... maybe a photo of how its attached and the focuser would help.

http://www.altairastro.com/images/D/coma-corrector-instructions-800w.jpg

Cheers

Russ

[cyberblitz]

Yes, the eye-piece holder can be removed. This would help except its needed to secure attachments. I tried without the eye-piece holder but the coma corrector was too loose in the focuser, with nothing to secure it in place. The bottom picture on the link you provided is exactly how it looks when everything is attached, but to focus i need the focuser to move closer to the secondary mirror, which it can't do...

[rustigsmed]

the eyepiece holder needs to be removed. how loose?
if too loose this may help? http://www.teleskop-express.de/shop/product_info.php/language/en/info/p4018_TS-Adapter-auf-2--mit-Ringklemmung-fuer-Skywatcher-Newtons.html
photos would help in seeing the issues.

Russ