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Processing C/2020 F3 Neowise

Posted: Mon Jul 27, 2020 12:44 am
by sandconp
I am trying to process the Comet Neowise using Star Tools and I am running into some issues. I have taken the same stacked fits file into Pixinsight with pretty good results.

I am started out by doing a Autodev to find the artifacts, then binning 50% and doing a wipe. I did not go any further because I feel that my results will only get worse. The wipe only fixed a part of the image the rest is white.

Would somebody be willing to take my image and provide a tutorial to process my image using Star Tools?

Here is the link via Dropbox.

https://www.dropbox.com/s/k49ytqgz46qcg ... .fits?dl=0

Re: Processing C/2020 F3 Neowise

Posted: Mon Jul 27, 2020 1:26 am
by admin
Hi,

I just had a quick look, but cannot replicate the problem you are describing? :think:

Did you maybe forget to crop out stacking artifacts before running WIpe?

Re: Processing C/2020 F3 Neowise

Posted: Mon Jul 27, 2020 1:47 am
by sandconp
Hi Ivo,

Can you tell me the steps that you did to start the process?

Did you use AutoDev or Dev?

Re: Processing C/2020 F3 Neowise

Posted: Mon Jul 27, 2020 2:03 am
by admin
sandconp wrote:Hi Ivo,

Can you tell me the steps that you did to start the process?

Did you use AutoDev or Dev?
I did as you did;

AutoDev to find artifacts/evaluate, Bin 50%, crop artefacts (X1: 13px, X2 -4px, Y1 39px, Y2 -4px), Wipe.

A subsequent AutoDev should get you this;
StarTools_169.png
StarTools_169.png (565.78 KiB) Viewed 661 times
Does this not work for you?

Generally, if Wipe is leaving in gradients, there is an artefact located near them.

Re: Processing C/2020 F3 Neowise

Posted: Mon Jul 27, 2020 2:37 am
by sandconp
Ivo,

I am kind of stuck here. I did an Autodev and then a Bin @ 50%

Those values X1: 13px x2-4px Y1 39px, and Y2-4Px) are very low. They hardly include any of the image.

Do your values x1-x2 Y1 and y1-y2 get put into those four boxes before proceeding to the subsequent AutoDev?

Re: Processing C/2020 F3 Neowise

Posted: Mon Jul 27, 2020 2:51 am
by admin
The negative numbers for X2 and Y2 are the offsets from the maximum (e.g. the second number between brackets).
Regardless, I am really confused as to why you cannot see/detect the stacking artifacts visually? E.g you should not need to guess or anything like that. The AutoDev should make them readily visible when zooming in and inspecting the edges.
It goes without saying that those observations as to their location are meant to inform the values for the Crop...

Re: Processing C/2020 F3 Neowise

Posted: Mon Jul 27, 2020 5:16 am
by sandconp
Ivo,

Ok I now see the artifacts on the top and on the left side and I understand the x1,x2,y1 and y2 settings.

So here is where I am after the second autodev and first wipe.

What are the next steps may I ask?

I just did a keep and I am ready for the next step(s).

Re: Processing C/2020 F3 Neowise

Posted: Mon Jul 27, 2020 6:12 am
by admin
Excellent. :) Sadly, it doesn't seem any calibration frames (flats) or dithering were applied, so the image suffers from vignetting and walking noise.

The Vignetting preset may or may not be more appropriate.

From there I would keep it really simple, given there is usually not much to enhance in the way of detail. So, I'd do an AutoDev again for final stretch, run the Color module (you'd be looking for a green core/C2 and beige/white tail with for the sunlight reflected dust, as well as an ionised blue CO streak), then switch Tracking off with a pretty aggressive noise reduction to catch most of the walking noise. You may want to bin more than 50%.

E.g. something like this;
Stack_32bits_124frames_248s.jpg
Stack_32bits_124frames_248s.jpg (65.33 KiB) Viewed 651 times
Hope this helps!