Odd mark on all images and flats

[Rattler]

Hi guys. I have a strange mark on my images and flats. It's like a mottled or spoty thing and seems to be more centre on the upper part of the image. I've attached a master flat which shows it but the flats don't remove it from the images. Any ideas? Cheers.

[Rattler]

[michael8554]

Which camera would help. 

Could be a Bayer display problem, or maybe ice or condensation  on a cooled camera? 

Michael 

[Rocket Stars]

I had similar problem. But much worse. 

Could not get rid of the with calibration files. Turned out to be smudge in the sensor. IPA solved the problem. 

Had a IPA beer, while I carfully cleaned the sensor with IsoPropanolAlcohol. 😬😁

[Rattler]

10 hours ago, michael8554 said:

Which camera would help. 

Could be a Bayer display problem, or maybe ice or condensation  on a cooled camera? 

Michael 

ASI294MC Pro cooled to -10. I've been told it may be freezing up. I'm going to recharge the dessicant tablets.

[Rattler]

2 of the desiccant tablets crumbled as I removed them. 

[david_taurus83]

I've seen this before on a similar thread. Pretty sure it was condensation frosting up on the sensor. Does that camera not have the tube attachment on the side to recharge the dessicant or did you have to remove the front?

[tomato]

It does look like moisture or ice crystals, and crumbly desiccant tablets doesn’t sound good.