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Having trouble lining up rings of Saturn in post processing

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#1 NightSkyD

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Posted 02 August 2021 - 10:38 PM

Well I got lucky last night and early morning today. I had a window of opportunity for about four hours with clear skies believe it or not (skies have been terrible the last couple of months) to image Saturn at opposition, but it was still slightly hazy and humid near Houston, TX. So I think the below average seeing conditions may be the issue I’m having. I processed one of the AVI files and I’m having trouble with lining up the rings of Saturn. I’m guessing this is due to poor seeing conditions but since I’m new to AP maybe others can chime in on what I did wrong. I first processed the file in PIPP then in Autostakkert and finally in Registax 6. I even added some additional larger AP points in Autostakkert along the rings and that didn’t seem to help. Here is what the result was:

 

Attached File  A1009FAC-481A-48AA-A5C4-2F20A685B34B.tiff   10.79KB   64 downloads



#2 Kokatha man

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Posted 03 August 2021 - 09:57 PM

Ok - you've got my attention! grin.gif

 

Post as suggested in Frank's thread - I cannot open this even though it says it's a tif...P/shop can't identify it for me.

 

I posted this thread particularly for people wanting a handle on how to arrange the MAPs in AS!3 recently: https://www.cloudyni...pot-animation/ 

 

Look down the page to see those AP suggestions - if you're having trouble getting a clear. clean Cassini Division try the MAPs on the ring as per the images I posted there - you don't want large ones for that btw & it may not work, but it does sometimes...it's usually a seeing situation.

 

When you post an image here that I can view I'll come back & comment further...others may also but make sure you don't just accept what is posted without checking out the credentials of the poster..! lol.gif

 

The internet is full of misinformation! grin.gif


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#3 RedLionNJ

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Posted 04 August 2021 - 10:04 AM

Ok - you've got my attention! grin.gif

 

Post as suggested in Frank's thread - I cannot open this even though it says it's a tif...P/shop can't identify it for me.

 

It's a TIFF alright:

 

A1009FAC-PNG.png

 

I'd look at Darryl's referenced link. The noise level also appears extremely high in this image - not enough frames?



#4 NightSkyD

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Posted 04 August 2021 - 08:49 PM

OK so here it goes. I uploaded the processed JPEG file from another AVI video with a longer exposure time of 591ms and a lower gain of 16 to reduce noise in image. The reason I shot a shorter exposure time for the AVI file used to the process the previous uploaded tiff image was because of the seeing conditions with haze, humidity and a slight breeze.

 

Here is an image after post processing by using Kokatha Man’s suggestions from a previous post that he mentioned earlier in this post for processing Saturn. I’m also uploading a screenshot of the MAP’s of how I placed them according to his suggestions. I’m not sure if this image is much better. It seems as if there is a misalignment of images. If you zoom in on the image you can see a ghost of rings super imposed on each other at different angles. I thought that the PIPP app was to align all the individual frames in a video so that you don’t get this problem. Could that possibly be the problem? I’m not sure if this is all due to bad seeing conditions or my poor post processing but I think it’s the former. Here are the pics of Saturn post processed and the MAP screenshot:

 

A3F9A925-C230-4474-AE66-6799028F3EF7.jpeg

 

775A02AB-C18B-4D6C-B67F-27E073274B17.jpeg
 

 

 


Edited by NightSkyD, 04 August 2021 - 08:53 PM.


#5 Kokatha man

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Posted 04 August 2021 - 09:36 PM

<"I uploaded the processed JPEG file from another AVI video with a longer exposure time of 591ms and a lower gain of 16 to reduce noise in image.">

 

First, don't use jpeg files out of AS!3 - they are only for posting images to be clear, output .tifs from AS!3.

 

Second, an exposure time of 591ms is less than 2 frames per second & a gain of "16" is ridiculously low...I'm assuming you're using the ASI120MC camera & using FireCapture for image capture..?

 

With exp. 591ms & gain "16" you are making things far too difficult - exposure determines fps (frame-rate) & as an example 10ms = 100fps...20ms = 50fps etc but you also need to adjust the ROI (region of interest) to enable faster frame-rates. Specifically the "height" of any ROI you select but capture in avi format (8 bit) & have the "High Speed" checked under the "More" tab's dropdown menu.

 

The gain determines the histogram you set - a bit confusing when a lot of people think exposure = histogram lol.gif but you aim for a histogram of about 60%+ with the ASI120MC because it doesn't like going too much below this because artefacts "can" occur if you do.

 

<"I thought that the PIPP app was to align all the individual frames in a video so that you don’t get this problem. Could that possibly be the problem?">

 

AS!3 is perfectly capable of doing this without PIPP - PIPP is really only useful imo if you have a lot of frames during the capture where the planet is half off the capture screen etc, as when you image in very windy situations. But used correctly PIPP before AS!3 shouldn't cause problems, just unnecessary most of the time!

 

<"Here is an image after post processing by using Kokatha Man’s suggestions from a previous post that he mentioned earlier in this post for processing Saturn. I’m also uploading a screenshot of the MAP’s of how I placed them according to his suggestions.">

 

Unfortunately I cannot see from you images what size you set the AP's at - I can see that you drew 2 like I tried to demonstrate but taking into account the size of your image the AP's you placed on the rings etc are still outside those 2 drawn ones at the top.

 

The "non-drawn" AP's are also far too big for the size of the image...in my example the size of the planet is the capture size...in your smaller image you have to scale down the AP size & make the 2 drawn ones at the end of my example encompass all these as per my images & text.

 

You're also not equally-spacing those you've placed along the rings, some places are missing an AP & they are not regularly placed along the rings as well...

 

Before you place the AP's on the planet in AS!3 you really should run the "Analyse" stage of AS!3 to get a quality-ordered sequence - your image is blurry & by "Analysing" first you can use the first frame in the series which should be the sharpest/clearest to place AP's on...it is not necessary to place the AP's before you run the "Analyse" stage of AS!3 btw..!

 

<"If you zoom in on the image you can see a ghost of rings super imposed on each other at different angles.........................................................I’m not sure if this is all due to bad seeing conditions or my poor post processing but I think it’s the former.">

 

Collimation, poor focus & poor seeing are all very likely problems unfortunately; the ploy of placing AP's along the entire ring (as per how I demonstrated) can sometimes alleviate the split Cassini Division at the ansae (ends) of the rings in certain seeing conditions, but it is far from foolproof - collimation & focus also require a minimum of decent seeing to be able to be obtained also. wink.gif


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#6 NightSkyD

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Posted 05 August 2021 - 04:49 PM

I would like to thank you for responding and spending the time to answer my questions obviously you’ve been at this a while and I appreciate your input. And you’re correct about the Internet giving all kinds of advice that might not be factual. OK to respond to your input and answer some of the questions.

 

First, you mentioned that I should not use JPEG files out of AS!3. I only export the JPEG file after I have processed it in Photoshop. Anywhere along the line in the workflow before that is a tiff file even out of AS!3. I know and understand that tiff files are lossless.

 

Second, the exposure time and the gain settings I mentioned earlier in this thread is only one of 6 iterations of exposure and gain combinations. The settings I used for Saturn are:  7.36 ms,100g;  9.27 ms,91g;  19.4 ms,100g;  33.8 ms,47g;  42.5 ms,91g;  591ms,16g. The reason I used different variations was due to the seeing conditions and a slight breeze so that I might have a chance to a fast or correct exposure time and gain combination that would work.

 

Third, You are correct I used the ASI120MC for image capture, but used SharpCap for acquisition.

 

This may be a stretch and I understand if you do not want to do it, but if there is a way to send the AVI file to you could you process it? That will definitely answer if it’s my processing workflow and abilities or if it’s seeing conditions or something else. BTW I looked through your gallery of images and I’m quite impressed. I inspire to be half as good as that with my images as time goes on.


Edited by NightSkyD, 05 August 2021 - 04:56 PM.


#7 Kokatha man

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Posted 05 August 2021 - 08:53 PM

...just saw this.

 

<"the exposure time and the gain settings I mentioned earlier in this thread is only one of 6 iterations of exposure and gain combinations. The settings I used for Saturn are:  7.36 ms,100g;  9.27 ms,91g;  19.4 ms,100g;  33.8 ms,47g;  42.5 ms,91g;  591ms,16g. The reason I used different variations was due to the seeing conditions and a slight breeze so that I might have a chance to a fast or correct exposure time and gain combination that would work.">

 

\What you want are the most frames in a single capture, which for Saturn is limited to 6 minutes. The gain determines the histogram & for Saturn, as I said, a histogram around 60% with the ASI120MC is a good value.

 

I'm presuming this is a Celestron 6SE so the aperture will influence just how much gain you need to apply with any specific exposure/fps but without using SharpCap those gain values are meaningless to me unfortunately.

 

But as a really rough suggestion I'd keep the gain to 70% or lower than its maximum capability & tailor the exposure/frame rate to get the fastest fps & that 60% histogram...others who use/d this scope might have better suggestions there.

 

First-up why don't you post the .tif out of AS!3 here for a few of your trials - just convert them to a web .png of .jpg in P/shop (png-24 preferably) so that they are below the CN limit of 500kb which should be easy to do. wink.gif

 

This way we (me & others) can have a look & advise further before we start trying to send large files over the internet. wink.gif

 

 

 

 

 

 



#8 NightSkyD

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Posted 05 August 2021 - 09:02 PM

Will do I’ll try to do that tomorrow.



#9 NightSkyD

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Posted 06 August 2021 - 04:23 PM

OK here are the JPEG files from the AS!3 converted in Photoshop from the tif files.

 

4C190CD0-5050-45C5-8D90-2A6F05070EB4.jpeg

 

07E03F6F-0E9B-485A-BD1B-680552BB4BE5.jpeg

 

B1B3F614-C3AD-4506-8A15-8DB2D9C85AD7.jpeg

 

BD6C835B-FFB2-4CBA-9BBA-81EFED621A49.jpeg



#10 RedLionNJ

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Posted 06 August 2021 - 05:35 PM

 

First-up why don't you post the .tif out of AS!3 here for a few of your trials - just convert them to a web .png of .jpg in P/shop (png-24 preferably) so that they are below the CN limit of 500kb which should be easy to do. wink.gif

 

This way we (me & others) can have a look & advise further before we start trying to send large files over the internet. wink.gif

Yet you persist in posting JPEG files.... do you not really WANT help?



#11 NightSkyD

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Posted 06 August 2021 - 05:58 PM

Yet you persist in posting JPEG files.... do you not really WANT help?

What are you referring to? That is what Kokatha man said, to upload either a .PNG or a .JPG converted from the .tif file of AS!3 in photoshop which you had quoted in the last post. The following is what he said which again you had quoted in the last post:

 

Kokatha man said:
 

“First-up why don't you post the .tif out of AS!3 here for a few of your trials - just convert them to a web .png of .jpg in P/shop (png-24 preferably) so that they are below the CN limit of 500kb which should be easy to do.”


Edited by NightSkyD, 06 August 2021 - 06:01 PM.


#12 Kokatha man

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Posted 06 August 2021 - 08:00 PM

Although the typo says "of" it should read <"just convert them to a web .png or .jpg in P/shop (png-24 preferably)"> but the reason I suggested png-24 is because it preserves a bit more than a jpg...

But all of us want to be able to assist so there's no real drama...grin.gif

 

First up I think you can see that the first 2 images are very dim while the last 2 would be quite acceptable: this is where the info I mentioned about matching gain with exposure to get a reasonable histogram is important. (the first 2 would have had very low histograms)

 

So firstly you should be making sure you get a decent histogram (around 60%) by using enough gain with any specific exposure setting.

 

The exposure setting is important itself because that will set the frame-rate (fps) - that 20ms = 50fps etc I mentioned previously. You need to set the exposure to get a good frame-rate but without having to use more than (say) 70% gain to get that "decent"  histogram. 

 

I don't know how long you ran the capture for also - you should have captured for at least 6 minutes with the image scale you are posting these images at...meaning even at 50fps (the 20ms exposure) you would have had 18,000 frames to load into AS!3 if you used a 6 minute capture.

 

How many frames did you capture for these btw..? I suspect nowhere near that 18,000 figure & if I'm correct you would have limited AS!3's ability to get enough good frames to make a good stack of reasonable frames.

 

Although you asked me to process the image to find out whether you are processing correctly it is hard to really make an accurate comment considering the comments I made in Posts #5 & #7 & here.

 

Better that you set the MAP's as per my comments in Post #5 & go through the lot again - looking at that screenshot in Post #4 the image of Saturn in AS!3 looks much larger - are you posting these images & the earlier one at their capture scale or what..? 

 

The image scale is important because the ASI120MC has 3.75um pixels & you want to aim for approximately 5x that pixel figure as your focal length...meaning 5 x 3.75 = f19 or thereabouts which ought to include a 2x barlow in the imaging train.

 

If you didn't use such a barlow it limits the scale/optimum possibilities but no matter, although it is nice to know all of your parameters to advise you properly. wink.gif

 

So really, to prevent an endless merry-go-round on suspect data & processing, I think it far better that you set up for another capture where you take into consideration exposure, histogram, gain, length of capture & image scale - perhaps around a setting of exposure of 20ms with sufficient gain for a 60% histogram then post a png-24 of the stack you get from AS!3 with how you set the MAP's for said stack, keeping the scale of all images at the capture scale!

 

I'm happy to keep this thread going or you can start another thread...I'm sure other starters would like to follow it & although you might be a bit disappointed atm there's only one way to go - forwards! smile.gif

 

 


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#13 NightSkyD

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Posted 06 August 2021 - 08:40 PM

Yeah I don’t think there was a drama either so I’m not sure what was up with the comment from RedLionNJ, but I wouldn’t be here answering these questions for days if I didn’t want the help. Sooo to Move On…

 

I will mark this thread and the next time I have an opportunity, which hasn’t been very often in the last few months, I’ll try your suggestions for capture. In the meantime just food for thought I’m thinking of leaning more toward the seeing conditions from the humidity and haziness of the night. The reason why I say that is because Jupiter turned out much better but still had some slight ghosting in the image. I’ll post the image here of Jupiter I captured about an hour or two before imaging Saturn, which in the Houston area the longer you go into the night the more humid it guests. Here is the pic the same night just 1-2 hours before Saturn:

 

3D0982CC-6C06-45D6-B5FC-72D27C91C0E5.jpeg

 

 

Oh and by the way you are correct I did not come anywhere near the number of frames of your suggestion of 18,000. At the most I think they were closer to 3000. I let the capture run about two minutes. And the reason I did that was because of suggestions of imaging Jupiter for no longer than that because of the 10 hour rotation period of the planet. I just assumed that would be the case for Saturn as well. Again a newbie mistake. And again thank you very much for your time and input Kokatha man.


Edited by NightSkyD, 06 August 2021 - 08:46 PM.


#14 Kokatha man

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Posted 06 August 2021 - 09:21 PM

<"I’m thinking of leaning more toward the seeing conditions from the humidity and haziness of the night.">

 

One last comment before we head bush for (hopefully!) more imaging is that seeing is always the elephant in the room...& although Houston is on the coast compared to Dallas, I haven't seen Dallas George posting anything for quite some time: George is a very good Texan imager & I presume he's not having a good time with seeing tbh.

 

At the scale I image with using a C14 (approx. 6000mm f/l) the limit for Jupiter is 3 minutes & Saturn 6 minutes - at the scale the 6SE delivers with a 2x barlow (approx. 3000mm) you could go appreciable longer than that - there is a lot of **** on the internet (& even here) about "rotational blurring" but all the images on our website use those time-spans. ;)



#15 NightSkyD

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Posted 06 August 2021 - 09:46 PM

Oh one other thing now that you brought up the Barlow. I did use a 2x Barlow for those images but a caveat to that was that I forgot about removing my f/6.3 focal reducer. So instead of having 3000mm FL it would be 1890mm. I was imaging the moon the last time I used the scope and I forgot to remove it. I’m now beginning to make a spreadsheet for a checklist because all this information you have to learn in the beginning is somewhat overwhelming and it’s easy to forget a simple thing like removing a focal reducer.

 

Finally one more comment, the conditions were also exacerbated by the smoke from the West Coast fires and on top of that the golf coast has been having the Saharan dust come from Africa. One upside to that is we have had some superior sunsets! Also in May and June we had extremely higher than average rainfall and cloudiness. So in the last 2 to 3 months it has been just horrible seeing conditions to even get the scope out. Since I started this hobby in March of this year I’ve only had the telescope out maybe if I’m lucky a dozen times. And of course the first half dozen times were learning the set up and getting everything working together including calibrations. Ugh!


Edited by NightSkyD, 06 August 2021 - 09:55 PM.


#16 mayhem13

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Posted 07 August 2021 - 05:35 AM

Keep at it NightSkyD…….these are the same fellas (red lion included!) who helped me go from smudges to images that never cease to amaze friends, family and Instagram followers in less than a month! Some things I can share that really helped……

 

Use the histogram!…….get the avg up in the 50-60% range. The more gain needed, the more frames needed to cancel out the noise

 

Focusing is soooo critical. Not sure your method but I quickly learned that I needed an electronic focuser……manually turning and having the image spaz out each time wouldn’t cut it…..even though I had convinced myself the focus was spot on….nope….not even close

 

Make sure to us an IR cut filter….essential for contrast which improves the overall clarity and dynamic range……images before we’re like night and day after installing the filter.

I don’t do RGB alignment in AS anymore…..I use Registaxx for that…..and Saturn was the discovery…….AS can’t get the rings right in the process while RS seems to nail it in a single image. 
 

And of course….collimation……as tedious as it sounds, I do it every single session no matter. Now I don’t use an SCT so maybe they hold up better (my little C5 is spot on every time I check it shooting the moon and stuff) but better safe than sorry for planets. The clarity these folks get is small accumulations of perfection from every part of the capture sequence. Heck I had to change my hard drive to SSD to get my frame rate to 150fps…..and it was those differences that made all the difference in the final result. Red Lion really rammed home the importance of signal to noise ratio which became some evident the first time I stacked 20k images of Saturn during the wavelet process…..I could push sharpening soooooo much farther without the whole thing falling apart or even needing smoothing on some layers. With a small aperture like yours, high gain is inevitable….and getting rid of the associated noise essential.

 

Keep the images coming!….best new hobby I’ve taken up in decades!



#17 NightSkyD

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Posted 12 August 2021 - 03:52 PM

 

mayhem13 said:

 

Use the histogram!…….get the avg up in the 50-60% range. The more gain needed, the more frames needed to cancel out the noise

 

 

Kokatha Man Said:

 

What you want are the most frames in a single capture, which for Saturn is limited to 6 minutes. The gain determines the histogram & for Saturn, as I said, a histogram around 60% with the ASI120MC is a good value.

 

I’m going to try to imaging tonight and I was curious on what was meant by 60% histogram. Does that mean that 60% of the graph should be on the left side or is that the amplitude or peak of the histogram. I know this may seem like an ignorant question, but I’m new to this so I’m just wondering what 60% meant.


Edited by NightSkyD, 12 August 2021 - 04:46 PM.



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