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Old 09-11-2007, 11:04 AM
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programmer
Computer tragic

programmer is offline
 
Join Date: Oct 2007
Location: Cheltenham, Victoria
Posts: 494
Quote:
Originally Posted by iceman View Post
Focus was off?

Your secondary would not drift across the screen, but the shadow of your secondary (cast by an out of focus star) would probably do that.
Thanks iceman. I couldn't get an image from one end of the focuser travel to the other. A Barlow will fix this? I've seen discussions on this (moving primary up the tube, etc.) but I'm hoping I can get it going without mods.

Edit: yes I have read your 'astro with a dob' article where you say "The magnification is controlled by changing the focal length of your telescope, usually by adding a barlow lens (2x - 5x)." but not sure if this is a cert to work or not. If so I'm going out at lunch time and getting a Barlow, probably 2x.

2nd edit: just realised how dumb my comment above was, as I'm pretty sure the Barlow will only magnify the out of focus image.

Last edited by programmer; 09-11-2007 at 11:38 AM.
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