Sirius - Last night 20/1/09

[Deneb]

Hi

After the clouds had disapearred about 10pm, I took these shots of Sirius with a Canon 450D in prime focus on a skywatcher 200P, from RAW to JPG:

ISO 1600, 10secs :

ISO 400, 10secs :

ISO 400, 20secs :

[themos]

I wonder if that blue halo tells a collimation story...there's a bit of imbalance in the halo, can you see it?

[Deneb]

Mmmm, maybe - It is called offset, as you know fast newtonians suffer from this, thats the way it is.

Difraction Spikes usually indicate a good collimation with perfect focus ( someone please correct me if im wrong ) ! See this thread :

http://stargazerslounge.com/index.php/topic,31561.0.html

Me other pics may indicate what you may be wandering about :

http://stargazerslounge.com/index.php/topic,37812.0.html