Guidance please with processing comet

[happy-kat]

I have been trying for over a week to process my comet image, I have created flats after readfing they are not optional. I have followed many guides on here and have downloaded a sample file to follow a guide on that it was the recent Orion one and I can see that even doing the first autodev my image is widly different but it had improved after I had added flats.
So this is 20 lights
5 darks
15 bias
25 flats
60 seconds ISO 800 taken with a canon 1100d using a vintage 55mm lens f2.8
Stacked on the comet and stars using DSS. At this stage all looks very promising.
My images see sample attached looks spotty and rather sick and this is better than what it had looked like.

Sample of what is happening (Small).png (498.75 KiB) Viewed 6715 times

I have provided a link to the autosave fts file.
Any pointers greatly appreaciated.
Link to fts file.
https://drive.google.com/file/d/0BzE0Jr ... sp=sharing

[admin]

Hi,

Can you post the workflow you used to get to this image?

I came up with this;

Autosave002(3).jpg (60.91 KiB) Viewed 6707 times

Workflow as follows (tweak to taste obviously!);

--- Auto Develop
To see what we got. We can se oversampling, heavy noise, heavy gradients, red bias, heavy stacking artifacts.
--- Bin
To convert resolution into noise reduction.
Parameter [Scale] set to [(scale/noise reduction 50.00%)/(400.00%)/(+2.00 bits)]
--- Crop
To get rid of stacking artifacts and frame comet better (feel free to crop less of course!)
Parameter [X1] set to [50 pixels]
Parameter [Y1] set to [367 pixels]
Parameter [X2] set to [637 pixels (-1508)]
Parameter [Y2] set to [768 pixels (-660)]
--- Wipe
To remove gradient/bias.
Parameter [Dark Anomaly Filter] set to [6 pixels], in order to preempt any dead pxiels or 'dark' noise (usually a good idea with noisy data).
--- Auto Develop
ROI along comet nucleus and part of tail.
Parameter [Ignore Fine Detail <] set to [3.2 pixels] to optimise less for fine noise.
Parameter [Outside ROI Influence] set to [7 %]
--- Color
Parameter [Dark Saturation] set to [5.00]
--- Wavelet De-Noise
(note 1.4.300 alpha specific)
Parameter [Grain Size] set to [30.3 pixels]
Parameter [Read Noise Compensation] set to [16.54 %]
Parameter [Smoothness] set to [79 %]

Hope this helps at all!

[happy-kat]

Thank you, that helps a lot.
I followed the steps on this thread and used that provided file to see how it compared to mine and how it behaved.
http://forum.startools.org/viewtopic.php?f=10&t=698
It is like the noise doesn't really show until I try to process to bring out the detail.

Going forward I will try to collect 30 lights or more.
I am looking at getting a light pollution filter for my camera setup.
Must check the histogram before commiting to taking lots of shots.

[admin]

Thank you, that helps a lot.
I followed the steps on this thread and used that provided file to see how it compared to mine and how it behaved.
http://forum.startools.org/viewtopic.php?f=10&t=698
It is like the noise doesn't really show until I try to process to bring out the detail.

Going forward I will try to collect 30 lights or more.
I am looking at getting a light pollution filter for my camera setup.
Must check the histogram before commiting to taking lots of shots.

Glad I could be of help. Noise is the bane of our existence... More data will help immensely.

[happy-kat]

I have been improving processing skills on comet data with the help of a great video on YouTube using two stacks from DSS one on the comet the other on the stars then use of masks and layers in StarTools.
Re-processed comet Lovejoy form January 2015. The attached is the revisited output and I am much happier with it. The tail has been lost somewhat with file size reduction for upload. Next I will see if can find the exact stack set used on this thread to redo the same night's data.

re-processed

Autosave001 comet combined.ftsv1 rs.jpg (480.38 KiB) Viewed 5682 times