Faint pattern around bright stars

Colin Clackson

Hi Adam,

I'm sorry to trouble you with yet another question. 

I'm using an ASI 1600MM Pro camera with Antlia V-Pro RBG filters. I create master lights, with appropriate darks, dark flats and flats using the WBPP script (log attached). The resulting master lights show a faint pattern around bright stars. the pattern changes slightly depending on the filter colour and is least visible with the blue filter. I've attached an image (Screenshot 56) showing the same star in R,G,B and RBG. The pattern becomes more pronounced if BlurXTerminator is used (Screenshot 57). Have you run into this issue before? Any thoughts on cause?  

 

Colin Clackson

I have a bulb shot of Vega taken with the blue filter at gain 76 and a 3 second exposure. The pattern is odd to say the least.

BlockHead

This is microlensing reflections. That is what it looks like to me. 

Does your sensor have microlenses?

There isn't much you can do if from the sensor.

-the Blockhead

Mike Cranfield

The Panasonic sensor used in the ASI1600MM is know for this effect. If you want chapter and verse check out this thread on CloudyNights.

Colin Clackson

Apparently the ASI 1600 is known for this effect (my research was deficient it seems). I guess I'll have to figure out some way to eliminate it or reduce it in post-processing. 

Thanks for your replies

BlockHead

Uggh... that is not something that is easily handled on bright stars. The ST10XME used microlenses...I used this camera back in 2006-2010 I believe.

-The Blockhead

Colin Clackson

Yeah. I bought the 1600 used because it was about a1/3 the price of  at 2600. Penny wise / pound foolish. I might try playing around with the processes you discuss in your diffraction repair video concentrating on reducing the green, which appears to be the most distinctive portion of the pattern.

In an unrelated post ... I can't get imagesolver script to work on my calibrated luminance light frames. It works fine of the R, G, and B light frames. The script settings remain the same for all files.  Attached are the log files for luminance and a frame through a blue filter as an example.

Sorry to keep pestering you with questions. Hoping you see something obvious

Colin Clackson

Actually. Ignore my last inquiry. The culprit was the first file in the stack. For some reason it couldn't be solved and thus the integrated image couldn't be solved either. Sorry to have troubled you.