ABE to the power 20 and still.......

[Peter]

Hello Guys and Gals, had a great night out under the stars and began my imaging. First hurdle and I fall over, I seem to find a rhubarb and custard with a little pea sauce effect on my final image. No amount of DBE or ABE seems to be able to shift the colours completely, even after 20 attempts of DBE or ABE on the image still leaves the effect stated above. I have left a tiff file resampled to 6Mb on my dropbox account but if someone could inform me how to link to that image from here at least one problem will be solved.

[sreilly]

First thing is what camera/telescope are you using? And I don't see a link to your file anywhere.

[Peter]

Hi Steve, I have a Canon EOS1100D and it is on an EQ5 mount. I am trying to find out how to sort a link to dropbox as I have never used it before but I will try to sort it out ASAP. Because of the short exposures plus a short focal length of 180mm on my Canon 70-300 mm I didn't use any guiding. As mentioned I am trying to collect constellation images for my own benefit and as part of a longer project. It's just that the colours I am obtaining on my images never fluctuate or differ so the cause of the Rhubarb and Custard etc., are always there and no what I do with either DBE or ABE it still remains though fainter than the original and never do I achieve a natural background. Thanks for the reply and I will sort out the image link ......
                                            https://drive.google.com/file/d/0B6dmOP_VSZenY3BUbS0ydU5RM28

Decided to use Google a drop off hope link works

[sreilly]

In order, what processes have you used? Are these RAW or JPG camera files?

[Peter]

Steve, this is a resampled fits image to show the effect I am discussing, up to this point I have used DBE at default settings and ABE also at default settings. Subsequent manipulation on my part found me increasing and decreasing all the tolerances, shadows relaxation, smoothing factors and minimum sample weights. The image is a resampled 30% Fits of 16exposures at 40s each at 400 ISO, and the same number of darks, each exposure was calibrated and the Master Dark used on each image. Finally I used the image integration tool and the debayered the integrated image. And voila, this is the result. No flats were taken and no biases. No other image manipulation was used as my feelings were that acheiving a neutral background was my first task.

[sreilly]

Have you looked over this thread? http://pixinsight.com/forum/index.php?topic=2570.0 I'm no dSLR guy but I know there are certain processes that must be followed in order to render a successful image. I think you have several choice of the Debayer filter choice which if I remember correctly makes a big difference in the proper usage of the RAW files. Not sure how the BatchPreprocess script handles this but worth a look.

[sreilly]

The other thing to consider is the quality of each individual image. Have you looked at each to see what may be going on in each before combining? And why such a low ISO? Don't you typically use somewhere in the range of 1600 or higher?  As I said I'm not a dSLR guy but I think this is important. Have you used the camera long with success?

[Peter]

Thanks Steve you are wonderful to help me as you have done. I will check out all that you have advised and for that I am eternally grateful. As to why I used such a low ISO is purely down to my poor brain trying to follow in the footsteps of Akira Fuji and his constellation photography, then I realised a most important fact I am only Human and should leave that kind of expertise for a later day. Thanks again Steve, you sure are a Top Bloke......