Weird blue pixels in image

Mattm45

Hi all, I had taken a few stacked images of m45. And I noticed some blue pixels in my image. You can’t really see them you’d have to zoom or know where to look, but I thought this was odd. I did not have cooling on. There was some dew built up? Maybe it was the dew? I’d appreciate any help. Thanks

johnpd

Are you are doing live stacking with a color camera? Is your mount Equatorial or Alt_AZ? These are most likely hot pixels since you mentioned that you did not have cooling on. When I do live stacking, especially with my mount in Alt-Az mode and in hotter weather, I get strings of red, green , and blue pixels.

JohnD

Tech@ZWO

johnpd Could you share some fits file here? thanks,.

johnpd

Tech@ZWO

Here is one. It was a Live Stack of M63, 30 images 20 seconds each at -10° cooling. This was on an Alt-Az mount. I did not save the individual lights. Below is a link.

https://drive.google.com/file/d/10oaEwzksZNt4IGnhO8nyt1V98YI2_M59/view?usp=sharing

Corsair

I remember asking a year or so ago for hot pixel rejection in Live Mode for Live Stacking.

Not sure if it has been added or not but I did notice using calibration frames captured in Live Mode can help.

I do unguided EAA so Live Stacking in Live Mode is what I do.

Tech@ZWO

johnpd Thanks, i applied to the permission, and noted 'ZWO tech'

johnpd

Tech@ZWO

OK I did not set it up for shared access. I have fixed that so anyone with the link can now access it.

JohnD

Tech@ZWO

johnpd Thank you for your sharing, i get your image, it usually caused by the unmatched dark frames, the hot pixels do not been calibrated welll.
Retaking the darks should solve this.