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Comet Processing
Posted: Wed Jul 06, 2022 9:37 pm
by mbushee
Hi All,
Its been a while since I've been back here. I'm doing something a little different then what I have been doing. I'm trying to do a comet that I managed to get some data on. I'm going for a an image with no star trails or where distorted comet. I have two different stacks of photos one with the images stacked based on the comet and another stacked based on the stars. The only thing that I know is that I will need to layer two photos together which I have yet to do I'm sure its not to difficult. I guess my main issue is I'm not sure where to start.
Should I be processing the photo with good stars and try and extract the stars out for a layer then my question becomes do i need to try and somehow remove the comet from that image? Do each of the images need to be completely processed before I try and layer them? When I try to layer the images what format should the images be in. Maybe I missed it, but i didn't see anything on the forums on how to for Comets.
I guess I'm just looking for a process on how to do this like for example to do completely process image #1 and somehow try and extract the stars from the picture to create a base layer and then process image # 2 and some how try and extract the comet to overlay?
My other question is how do you recommend going about processing a comet. I ask as I've only done DSO up to this point. I've attached a link with the two files I would be processing. The comet is C/2017 K2 any help would be greatly appreciated as I plan on trying to image this comet again as it gets closer to the sun in hopes that the tail will be a little more prominent.
Thanks in advance to anyone that is able to help this newbie out.
https://drive.google.com/drive/folders/ ... sp=sharing
Matt
Re: Comet Processing
Posted: Thu Jul 07, 2022 4:49 am
by admin
mbushee wrote: ↑Wed Jul 06, 2022 9:37 pm
Hi All,
Its been a while since I've been back here. I'm doing something a little different then what I have been doing. I'm trying to do a comet that I managed to get some data on. I'm going for a an image with no star trails or where distorted comet. I have two different stacks of photos one with the images stacked based on the comet and another stacked based on the stars. The only thing that I know is that I will need to layer two photos together which I have yet to do I'm sure its not to difficult. I guess my main issue is I'm not sure where to start.
Should I be processing the photo with good stars and try and extract the stars out for a layer then my question becomes do i need to try and somehow remove the comet from that image? Do each of the images need to be completely processed before I try and layer them? When I try to layer the images what format should the images be in. Maybe I missed it, but i didn't see anything on the forums on how to for Comets.
I guess I'm just looking for a process on how to do this like for example to do completely process image #1 and somehow try and extract the stars from the picture to create a base layer and then process image # 2 and some how try and extract the comet to overlay?
My other question is how do you recommend going about processing a comet. I ask as I've only done DSO up to this point. I've attached a link with the two files I would be processing. The comet is C/2017 K2 any help would be greatly appreciated as I plan on trying to image this comet again as it gets closer to the sun in hopes that the tail will be a little more prominent.
Thanks in advance to anyone that is able to help this newbie out.
https://drive.google.com/drive/folders/ ... sp=sharing
Matt
Hi Matt,
Welcome back!
This is really a "PhotoShop"/art sort of question with no true one answer, and therefore a little beyond the scope of the design goal of StarTools.
Cometary photography typically shows the comet itself in focus, with the stars trailing, without further doctoring of the image. You should be able to use StarTools as normal for this.
Of course, it is possible to layer things selectively in StarTools though creating a mask, healing, etc. (likely with decent results), but it will never be a true photo, and hence it is not a common practice...
Re: Comet Processing
Posted: Thu Jul 07, 2022 12:43 pm
by mbushee
Hey Ivo,
I actually was thinking about this after I posted it. What I was trying to do is not a true scientific representation of the comet and that might be the response I got.
So my follow up would be so you have any tips for processing the comet with star trails? I've only imaged DSO nothing this close to home and moving across the sky like this. I never processed anything with intentional star trails.
Also like to say thanks for the great software Ivo. I have no previous photo editing experience and your software is amazing I don't plan on switching. I've started astrophotography in March and I can see improvement in every photo. I'm slowly learning more and more about the capabilities of this software.
Matt
Re: Comet Processing
Posted: Thu Jul 07, 2022 6:16 pm
by Mike in Rancho
Hi Matt,
Have you tried any of the built-in comet routines? DSS has three options, depending on what you want to "freeze in time," or an attempt to do both. I don't know how that would compare to trying to reach the same effect with two finished images.
If they are already registered though, then it would seem to be a layer job, with a mask and some fuzz, and experiment with the blending mode and parameters.
As Ivo notes, this is a bit more artsy, but not uncommon, and for a reason. Kind of like landscape astrophotography of oh, mountains and the Milky Way. Perceptually it just doesn't "feel right" without freezing both. Though I suppose star trails can be stomached more than blurred landscape.
Re: Comet Processing
Posted: Thu Jul 07, 2022 9:59 pm
by mbushee
Hey Mike,
I did try the DSS feature it turned out to be a Frankenstein mess lol unless I did something wrong. The one I stacked based on the comet turned out how I expected it to. With star trails and it does look neat at least the unedited version. It's in the link I shared if you are interested in seeing it.
I'm okay just using the one with star trails to get a more scientifically accurate version of the photo. My problem lies in the fact that I've never edited anything within our solar system. I tried starting out with the process I use for DSO and it was way to bright. I guess I'm just looking for some tips if anyone has any.
Also curious to what modules I should run I would think I could cut out a large portion of the modules. I'm not even sure HDR would be beneficial. I was thinking contrast, sharpness, I'm guessing decon would be pointless unless maybe you could get it to tighten up the comet itself a tiny bit. Was thinking maybe the superstructure possibly. Usually I do alright, but I was struggling a bit with trying to figure out the best area for second autodev. I Was also wondering if the first autodev used for the wipe would be messed up by the star trails. I guess those are the things I'm struggling with lol. Do you have any tips regarding that Mike?
Thanks,
Matt
Re: Comet Processing
Posted: Fri Jul 08, 2022 5:38 pm
by Mike in Rancho
Hi Matt,
Same here as to comets, I've only taken single shots and never stacked, so I wouldn't know how to process. I have used ST for Jupiter and Saturn (I am very beginner at those), and the deconvolution planetary mode is pretty awesome.
I did try your two files - of them, I think the frozen stars turned out better. But really I couldn't get much out of either. The noise level as well as the short star trails made me think the total integration here is pretty short, and thus maybe insufficient increase of SNR really to get a clean comet tail.
But there did seem to be a good chunk of green, which is possibly appropriate?
But yeah I had to squash the background so much that overall I couldn't seem to do much. I used contrast and lowered the shadow dynamic range, skipped HDR, and did try out SS-dim and SS-isolate, then some strong DN to try to smooth out the tail.
The first AutoDev is really just to get a look-see and take care of things like your cropping needs. Wipe will hyperstretch to its best ability from scratch, based on your settings, DAF, whatever cropping you did, and mask if used, so I wouldn't otherwise worry about the first AD. The second and "final" AD will be where you decide what kind of stretch your SNR allows you.