Help with M104

[mhamburg]

I am having some trouble getting through a workflow for M104. Without doubt I need lots more practice. I am including a link to the original .fts file -
20x120s @iso1600 with Canon 40D @ 2800mm. I am also including a .tiff file I played with in Irfanview. The colors seem off (among other things.) I appreciate all the help.
Michael

https://www.dropbox.com/s/wqr6awk4mw83unc/M104.fts?dl=0
https://www.dropbox.com/s/ing3qv73c5jm3jb/M104.tiff?dl=0

[admin]

Hi Michael,

I had a look at your data (thanks for uploading!)
To me, something doesn't seem quite right - to my eye there appears to have been some sort of pre-processing filtering applied... (and at the very least it has been pre-color balanced) How did you stack the CR2s? Did you use any other software in between putting them through the stacker?

In general, have a look in the new website/documentation on the various ways you can colour balance your data and what to look out for.
The 'Band' module will also help you somewhat with ameliorating the horizontal banding.

[mhamburg]

sized_M104.jpg (11.16 KiB) Viewed 9447 times

So I kept running and rerunning my data through StarTools until I got something that looked better than a bad picture on a 1950 television. It really takes a lot of experimenting to make improvements. Here is a resized sample of M104. I think that I need longer subs and more of them. Thank you Ivo for all your support.
Michael

[Rowland]

Hi.

How did you preprocess your subs?

[mhamburg]

I ran them through DSS.

Michael

[Rowland]

Can't download the fits file. Not present it says? Can you upload again, please?

The pixel values in your tiff are very low. The figures displayed approximate dark frame values from my DSLR. I think the data is clipped. Not unusual with DSS from what I can see. Maybe some of the other users can point you to the correct settings, but I recommend you change your preprocessing method. It will make a world of difference. Hope this is in the right direction. Looks like a great image.

[mhamburg]

Hi Rowland,
Let me try a link to the .FTS file in Dropbox. I would surely appreciate how to fine tune these settings. Thanks.
Michael
https://www.dropbox.com/s/wqr6awk4mw83unc/M104.fts?dl=0

Update: I have just attached a resized (in BD Sizer) version of one of the original light raw files Maybe thiis can be of help.

sized_LIGHT_120s_1600iso_+13c_20150418-23h08m29s716ms.JPG (232.27 KiB) Viewed 9412 times

[almcl]

I'm certainly no expert, but looking at the FITS file, there seems to be an issue with either focus or misting in the optical train somewhere. I've not personally seen an effect like that in the screen shot below but the Maltese cross effect around the brighter stars prompts me to ask what focussing method you use?

[mhamburg]

Capture and focus was done with BYEOS using the lowest FWHM (Full Width Half Maximum) value I can get.
Michael

[almcl]

Unlikely it's a focus issue then, any chance there was dew or mist on any part of the optical train? (Clutching at straws a bit, I admit!)