Struggling with DSS Comet Stacking mode

[michael.h.f.wilkinson]

I tried comet stacking mode in DSS but struggle with a couple of things. First, DSS seems to butcher colour in the images (checked the right mode, even let it stack full colour fits files produced with APP). When selecting the cometary nucleus it refuses to lock on to the bright spot (which it did manage before in shorter exposures). It probably wants a stellar nucleus, so I found the way of indicating the core using the shift key. It then infuriatingly fails to stack on the comet. Modes "Stars + Comet", "Comet Only", and the default stars option all give the exact same result (with buthered colours added). Has anybody else encountered these issues?

 

[Victor Boesen]

I had the same issue which I ended up only solving by stacking less exposures so the comet didn't trail. I also tried stacking the comet and stars separately and manually blending them together afterwards but it just didn't really work out. 

I'll follow along here for any solution to this!

Edited July 13, 2020 by Victor Boesen

[michael.h.f.wilkinson]

I got the data with a tracking mount, but would like to combine more data than is possible with the time restriction imposed by the comet's motion. I am now trying to stack the comet separately from the stars, and if that doesn't work, I think I will have a go at writing my own code, using so-called connected filtering approaches

[carastro]

I'm afraid to say I had the same problem with DSS when Comet Jaques was around.  In the end I just stacked them manually in Photoshop, bit long winded but it worked.

Carole 

Edited July 13, 2020 by carastro

[happy-kat]

DSS in comet mode from my testing only now works if use comet and stars, the other options are poor, this used to work many earlier version ago. You will probably find it better to remove the stars from your comet and star stack and process and then blend a separate star only processed image.

[michael.h.f.wilkinson]

11 minutes ago, happy-kat said:

DSS in comet mode from my testing only now works if use comet and stars, the other options are poor, this used to work many earlier version ago. You will probably find it better to remove the stars from your comet and star stack and process and then blend a separate star only processed image.

Comet and stars doesn't work either. I think it is struggling with the non-stellar nucleus. I can readily think of ways to solve that. I might try some tricks when I get back to the office, and have more serious image processing tools at my disposal 

[Mangifigeek]

Sunday was my first attempt at using DSS for comets!

I had some success if trailing stars or the comet is moving ("standard mode") - but standard mode looks quite silly. I did manage one stack in the combined mode - but it always hung after that at the final stage and I had to kill the process.

It was interesting stacking the first and final image over a 90 minute period and seeing how much the comet had moved relative to the background stars.

The attached photo was based on just a handful of the lights I had taken (they were very short ones). Anything more caused DSS to hang.

I am following the thread with interest, and I may consider doing the stacking in PixInsight when I have time.

[happy-kat]

I am currently fast crash learning as I go using Siril.

Edited July 14, 2020 by happy-kat

[geoflewis]

I found this thread by Tony Cook on Astrobin. I've not tried it myself, but it sets out what to do....

https://www.astrobin.com/151422/

[Paul M]

After much frustration with my limited data on comet Atlas earlier this year, I eventually got the cursor to lock on the comet nucleus while aligning each frame.

There is a keyboard shortcut or key press or something. Sadly, lacking a memory, I can't remember what it was! Google came to my rescue and I'm sure it referred me to an old SGL thread. 

Anyway, once I got that sorted it was quite easy to stack on the comet nucleus, if slightly labourious

[happy-kat]

In DSS it is hold shift key down to be able to free move the selecting box over the comet then save

 

Though I just managed to get DSS to stack on the comet and stars, the difference was a removed every fake star that had been picked up in my static foreground. But I don't really have a usable image and I suspect this might be down to the sky getting progressively lighter as it was sunrise.

Edited July 14, 2020 by happy-kat

[michael.h.f.wilkinson]

27 minutes ago, happy-kat said:

In DSS it is hold shift key down to be able to free move the selecting box over the comet then save

 

Though I just managed to get DSS to stack on the comet and stars, the difference was a removed every fake star that had been picked up in my static foreground. But I don't really have a usable image and I suspect this might be down to the sky getting progressively lighter as it was sunrise.

I did hold the shift key and  marked the comet's nucleus, but to no avail.

[Mangifigeek]

Just now, KevS said:

I am getting the same problem, use the shift button to get the cursor over the comet run the stack and then DSS hangs up (computing final image). Might be missing something here but I have tried all of the possible combos; locate comet before register, after register but before stack still get the same problem and all of the permutations within DSS with/without star alignment etc. May have another run at it this evening, as someone has mentioned Siril might give that a try if all fails (again).

I guess DSS has never been so heavily used before for such a great comet!

[happy-kat]

I've not had issues before but this is the first time stacking data that isn't an expected dark sky but near daylight. My 100 odd images are stacking but I've a comet but no stars at all

[michael.h.f.wilkinson]

In my case there were quite a few stars. AS!3 managed to stack on the comet, however

[happy-kat]

I have been playing with Siril, which at least dealt better with the day light colours and was more successful might be worth you trying that for comparison. I found a pdf on how to go about comet stacking which helped as I had missed a step off on self using.

 

 

Edited July 15, 2020 by happy-kat

[Mangifigeek]

13 hours ago, happy-kat said:

I have been playing with Siril, which at least dealt better with the day light colours and was more successful might be worth you trying that for comparison. I found a pdf on how to go about comet stacking which helped as I had missed a step off on self using.

 

 

It would be great to see some of your results 🙂

 

[michael.h.f.wilkinson]

I posted an experimental image with stars removed here:

 

[vpsj]

I've read all the comments above but I still can't get DSS to work. The problem is I took all my shots of the comet Neowise using a 300mm lens(untracked). I only have two stars at max in my frame that were near the comet.

Because of this, DSS basically refuses to stack my shots with auto-alignment, as it can only see 2-3 stars at max instead of the minimum 8. I even marked the comet in all the frames manually, and selected no alignment mode to stack all of them. That just resulted in a completely gray image, with no comet at all.

Can anyone please help me out. Is there a different program that works better on comets? I tried searching for any tutorials on Comet stacking but I can mostly only find DSS based tutorials, and none of them qualify in my case. Please help me. Thank you

[geoflewis]

19 minutes ago, vpsj said:

Can anyone please help me out. Is there a different program that works better on comets?

I use ImagesPlus which used to be a commercial product, but has recently been made available to all for free, by the developer Mike Unsold. EDIT (N.B. it is no longer supported by Mike hence being free).

It has a TSR (Translate, Scale, Rotate) Align tool that will allow you to stack on just the comet head. You can download the application from Mike's website... http://www.mlunsold.com/ILOrdering.html

There are 2 products, you need IP6.5 Image Processing, NOT the Camera Control (though you can try that if you want to). Make sure to note the serial number that you'll need to register the product and also note that you need to run as admin the first time in order to register it.

Good luck.

 

 

Edited July 19, 2020 by geoflewis
Product now unsupported, hence free.

[Xiga]

On 19/07/2020 at 20:39, vpsj said:

I've read all the comments above but I still can't get DSS to work. The problem is I took all my shots of the comet Neowise using a 300mm lens(untracked). I only have two stars at max in my frame that were near the comet.

Because of this, DSS basically refuses to stack my shots with auto-alignment, as it can only see 2-3 stars at max instead of the minimum 8. I even marked the comet in all the frames manually, and selected no alignment mode to stack all of them. That just resulted in a completely gray image, with no comet at all.

Can anyone please help me out. Is there a different program that works better on comets? I tried searching for any tutorials on Comet stacking but I can mostly only find DSS based tutorials, and none of them qualify in my case. Please help me. Thank you

If you have Photoshop and are up for doing it manually, then you can actually stack in PS. It won't be as good as using DSS or the like, but it might get you out of a jam. Have a look at this video, it shows very well what you need to do:

 

[michael.h.f.wilkinson]

52 minutes ago, Xiga said:

If you have Photoshop and are up for doing it manually, then you can actually stack in PS. It won't be as good as using DSS or the like, but it might get you out of a jam. Have a look at this video, it shows very well what you need to do:

 

Don't have photoshop, and am no fan of software rental model, so it isn't likely this will change.

[Xiga]

2 minutes ago, michael.h.f.wilkinson said:

Don't have photoshop, and am no fan of software rental model, so it isn't likely this will change.

No probs Michael. I was suggesting it for @vpsj 

[happy-kat]

There is a stack tool in Affinity photo, whether it handles comets versus just startrail images I don't know