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Old 13-04-2021, 03:32 PM
RugbyRene (Rene)
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RugbyRene is offline
Join Date: May 2015
Location: Sydney
Posts: 280
Images have a blue/salmon cast I can't get rid of

Hi all,

Hope someone can help me. Last night I had a fairly successful night of imaging. I managed to capture NGC3324, M83 and NGC6188 (2 panel mosaic). I stacked M83 in PI using the exact same workflow as always and when I opened the master and did a stretch I noticed a blue cast across the image. No worries, I thought, I'll use DBE and that will sort it out. Ran a DBE as I always do, re-stretched the image and the blue cast was still there.

I then stacked NGC6188 and got the same result. I stacked NGC3324 and this time I got a horrible salmon cast when I stretched it. The colours of the nebula look nothing like I got from the previous few nights. I imaged the previous 3 nights and the blue/red cast was removed as expected.

I'm running an Esprit 100, with an ASI294MC and IDAS P1 LPR filter. Nothing has changed in my set-up. No settings have changed in my capture or processing software.

The only thing I did, probably stupidly, was leave the scope out all day yesterday. It was covered by a scope cover and a towel so it was protected from the direct sun. It was only 21 degrees in Sydney but it was in the direct sun all day.

Oh the only other thing I did (again probably stupidly) is I had shone a flashlight down the OTA as it was taking an image as I wanted to see if there was dew forming on the lens.

So the question I have is has the sun fried my sensor? Is there a way I can test it to see if it is faulty?

I've attached a single sub that has been stretched. These were taken a couple of weeks apart. The first was taken last night for 180sec, the second was taken a couple of weeks earlier for 120 sec. The first image is not normal, The second is what I expect.

Attached Thumbnails
Click for full-size image (NGC_3324_image1.jpg)
194.1 KB48 views
Click for full-size image (NGC_3293_image2.jpg)
198.5 KB44 views

Last edited by RugbyRene; 13-04-2021 at 03:57 PM.
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