M45: Strange halo around bright star

Hello,

I recently shot M45 with my Canon Rebel and my newly acquired
150mm/750mm Newton telescope. I attached the resulting image which is
the sum of 20 5-minute exposures.

Here is the shot:  http://ivredimages.free.fr/M45.jpg

I noticed a weird halo around the main star and I do not know what
caused it. It was cold (- 2 °C) and there was some frost on the tube
exterior and the camera.

Any idea? Thank you.

date: Sun, 06 Jan 2008 10:40:17 +0100 author: tochiro

Re: M45: Strange halo around bright star

tochiro wrote:
> Hello,
> 
> I recently shot M45 with my Canon Rebel and my newly acquired
> 150mm/750mm Newton telescope. I attached the resulting image which is
> the sum of 20 5-minute exposures.
> 
> Here is the shot:  http://ivredimages.free.fr/M45.jpg
> 
> I noticed a weird halo around the main star and I do not know what
> caused it. It was cold (- 2 °C) and there was some frost on the tube
> exterior and the camera.
> 
> Any idea? Thank you.

probably reflection off ice crystals in the atmosphere ?

date: Sun, 06 Jan 2008 14:58:46 +0000 author: Mark McIntyre