Strange things on my images!

[CheapAsAstronomer]

Hi, first time posting here!

The last two images I took had strange blue/grey rings on them. Not sure what's caused them.

I'm using a Canon 1100d with an Evostar 72ed with a lens warmer. Wondered if the sensor needed cleaning? Or if I shouldn't be using the warmer during Summer?

These rings only come to light when processing after stacking. Was kind of hoping I'd discovered two black holes 😁

Any help appreciated!

 

Edited August 8, 2020 by CheapAsAstronomer
Extra info

[ollypenrice]

You've massively black clipped the data so we don't have a view of everything captured by the camera but this is very strange. What's needed is a link to the linear stack. (Stacked with no processing.)

Olly

[CheapAsAstronomer]

50 minutes ago, ollypenrice said:

You've massively black clipped the data so we don't have a view of everything captured by the camera but this is very strange. What's needed is a link to the linear stack. (Stacked with no processing.)

Olly

Ah. I'm on it.

[CheapAsAstronomer]

I think I've attached the file in .fts format.

Is that any good?

Autosave.fts

[CCD-Freak]

Did you calibrate with Darks and Flats?   Looks like "dust doughnuts".

 

[CheapAsAstronomer]

1 hour ago, CCD-Freak said:

Did you calibrate with Darks and Flats?   Looks like "dust doughnuts".

 

Dust doughnuts?

Yes, calibrated with darks, flats and bias

[CCD-Freak]

Try stacking the images without the flats and see if you still have the problem. 

I just downloaded  the file you posted and it looks like a problem with your flats.

 

 

Edited August 9, 2020 by CCD-Freak

[CheapAsAstronomer]

7 hours ago, CCD-Freak said:

Try stacking the images without the flats and see if you still have the problem. 

I just downloaded  the file you posted and it looks like a problem with your flats.

 

 

Thank you for that. I'll take a look

[david_taurus83]

How did you take flats? The Av method for exposure doesn't always work.

[ollypenrice]

Sorry but I can't download this file. Maybe too big for rural French internet!

Olly

[CheapAsAstronomer]

2 hours ago, david_taurus83 said:

How did you take flats? The Av method for exposure doesn't always work.

Exactly that. AV and aimed at White screen on laptop.

[CheapAsAstronomer]

1 hour ago, ollypenrice said:

Sorry but I can't download this file. Maybe too big for rural French internet!

Olly

Ggrrr!!

[david_taurus83]

5 minutes ago, CheapAsAstronomer said:

Exactly that. AV and aimed at White screen on laptop.

Some people swear by that method, I havr found it under exposes for my 6D. How did you stack and process your light frames?

[CheapAsAstronomer]

34 minutes ago, david_taurus83 said:

Some people swear by that method, I havr found it under exposes for my 6D. How did you stack and process your light frames?

Stacked in DSS using recommended settings and processed in Startools, again with recommended settings

[CheapAsAstronomer]

Ok so I stacked again with no flats.

Wiped the RAW file in Startools and got this:

[jager945]

Hi,

Crop away the stacking artifacts around the edges and fix your flats (these are almost definitely dust donuts). If you cannot (or don't want to) fix the flats, mask out the dust specks before running Wipe. Have a look at the Wipe documentation here which incidentally shows examples of the same issue you are experiencing above.

Hope this helps!

[MarkAR]

Just had a thought about the doughnuts, did your focus move when taking the flats ?

[CheapAsAstronomer]

3 hours ago, jager945 said:

Hi,

Crop away the stacking artifacts around the edges and fix your flats (these are almost definitely dust donuts). If you cannot (or don't want to) fix the flats, mask out the dust specks before running Wipe. Have a look at the Wipe documentation here which incidentally shows examples of the same issue you are experiencing above.

Hope this helps!

Excellent! Thank you!

[CheapAsAstronomer]

2 hours ago, MarkAR said:

Just had a thought about the doughnuts, did your focus move when taking the flats ?

There is a chance it could have....not sure if it did. 

[MarkAR]

13 minutes ago, CheapAsAstronomer said:

There is a chance it could have....not sure if it did. 

Try taking a couple more flats at the proper focus to see if the dust donuts are in the same place. If they are then take another set and try them for calibration.

[autonm]

Late to to the post .. but Ive created a video with APP for the stacking and then processing in Star Tools for M31 with the exact same camera that you have.

Please let me know if the video was helpful, I'm already working on further objects and workflows via You Tube. So please subscribe to be notified as they appear !

https://www.youtube.com/watch?v=xxkDDLspaiM

[CheapAsAstronomer]

On 13/10/2020 at 19:56, autonm said:

Late to to the post .. but Ive created a video with APP for the stacking and then processing in Star Tools for M31 with the exact same camera that you have.

Please let me know if the video was helpful, I'm already working on further objects and workflows via You Tube. So please subscribe to be notified as they appear !

https://www.youtube.com/watch?v=xxkDDLspaiM

Great video. Learned many things there!