#1  
Old 28-01-2013, 10:37 AM
orestis's Avatar
orestis
Registered User

orestis is offline
 
Join Date: Jun 2009
Location: southern highlands, Australia
Posts: 679
Achieving focus on a 12'' dob

Hi everyone,

Lately I have gained interest into astrophotography mainly from my recently purchased Canon 550 D.

I have taken some shots on a still tripod and stacked them with some pleasing results although an eq mount would ofcourse be better, though being a student its an expensive realm.

So I bought a t-mount and 2'' adapter. Attached it to the camera and slid it into the focusser only to get a a big blurry image of the moon. I tried focusing outwards and the image became more blurry. Focused inwards and the tube would not go any further in.

I have heard that, moving the mirror up would solve this problem. though I really don't want to be hacking away at the tube.

So if there is any other means of being able to achieve focus,please let me know.

thanks in advance, Orestis
PS- would a 1.25 '' adapter cause vignetting , because I have a small 5'' reflector I could try it on.
Reply With Quote
  #2  
Old 31-01-2013, 07:14 AM
Shiraz's Avatar
Shiraz (Ray)
Registered User

Shiraz is offline
 
Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,918
you might try a 2x 2 inch Barlow, which should get to focus without moving the mirror (1.25 is too small). will give you additional magnification, but that should be OK on the moon and planets. Barlow will also help with your "bunch of Plossls" - they will work a bit better with a reduced light cone angle (higher magnification though). I have one of the GSO 2 inch Barlows - something like that should be suitable. If you know anyone with a Barlow, try it out before purchase just to be sure that it will work with your scope geometry and focuser design - and that everything fits.

Last edited by Shiraz; 31-01-2013 at 06:50 PM.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 07:07 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Testar
Advertisement
Bintel
Advertisement