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Here's one to slap your forehead about! - AP's in AS!3

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#1 dcaponeii

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Posted 27 July 2021 - 12:14 PM

For going to TWO years since I was introduced to this endeavor it looks like I've been using AS!3 incorrectly.

 

I just realized that I have been placing my AP's BEFORE analyzing the video.  When the light bulb went off twenty minutes ago it dawned ("Don"ned) on me that if you follow the procedures (in like ALL of the tutorials I've watched over the months as well as the NUMBERED steps on the software itself) it turns out that after you analyze the video then the image that displays in the preview window is the BEST image in the stack.  This image is MUCH easier to place AP's on in precise locations.

 

UGH.  Already seeing improvements in the first few attempts at doing things the right way round.

 

Note:  Doesn't fix my collimation issue at all but it DOES appear to allow me to properly stack only those best images in which the details were actually in focus.


Edited by dcaponeii, 27 July 2021 - 12:14 PM.

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#2 RedLionNJ

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Posted 27 July 2021 - 01:12 PM

You're only partly correct, I think.

 

Depending on the Quality Estimator option (Local or Global), you'll notice "Local" is actually "Local ( AP )".  If you're going to use Local as your quality estimator method, then you should indeed place APs prior to clicking on "2) Analyze".

 

This is where I'm fuzzy on the next step (Emil, do you still read these forums?).  Let's say I selected "Local ( AP )" and placed ten APs on Jupiter.  When the frames are sorted in order of decreasing quality and the "best" frame is displayed, is this best frame a composite of the individual best APs from the entire video, or is it determined by some other means?

 

Or, is the "Local ( AP )" option essentially meaningless?


Edited by RedLionNJ, 27 July 2021 - 01:12 PM.


#3 KiwiRay

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Posted 27 July 2021 - 01:32 PM

In the youtube video on the AS website, Emil discusses all of this in detail. He says "Local" works best in 99% of cases, and performs the analysis prior to placing alignment points.



#4 KiwiRay

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Posted 27 July 2021 - 01:41 PM

And yes, manually adding alignment points around features is much easier when you can actually see the features in the best frame, and not whatever random quality the first frame happens to have. Almost always, though, I use automatic placement with the multiscale option selected, which has worked great for Mars and Jupiter. I will add extra, smaller points (24 or 32) for Jupiter's moons after the autoplacement. I used to only manually add points to Saturn, but multiscale works well here too, and I may just add a small number of manual points if necessary to make sure the rings are well covered.



#5 dcaponeii

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Posted 27 July 2021 - 05:48 PM

I’ve been reprocessing images this afternoon by analyzing first and then placing AP’s (size 24) manually onto the moon’s or shadows in Jupiter’s surface. Once they are placed I let AS!3 place MAP’s (size 48) on the rest of the image. Of course you have to have “replace” turned off. I’m not finished yet but the results have been an improvement over previous attempts to process images from the weekend. I’ll be ready to post some results later this evening. Again not perfect but much better than my previous efforts. I’m certain that analysis followed by placing AP’s is definitely a better procedure that the reverse. I always use Local by the way.

#6 Tulloch

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Posted 27 July 2021 - 06:56 PM

I was of the opinion that it doesn't matter that much, by setting the APs before you analyse the video you are setting the AP location on the first frame in the video rather than the best frame in the video. Yes, the positions of the APs might change a bit, but it really shouldn't make that much of a difference... hmm.gif

 

Happy to be proven wrong though :).



#7 dcaponeii

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Posted 27 July 2021 - 07:14 PM

I was of the opinion that it doesn't matter that much, by setting the APs before you analyse the video you are setting the AP location on the first frame in the video rather than the best frame in the video. Yes, the positions of the APs might change a bit, but it really shouldn't make that much of a difference... hmm.gif

Happy to be proven wrong though :).


I don’t think it’s right or wrong. What I’m finding is that in bad seeing if I’m manually placing AP’s on moons for example I can place a smaller AP more accurately centered on the moon that I can when I’m looking at just the first image. Unless it just happens to be a high quality frame the blurring makes it tough to identify the centroid of the moon in question.

#8 Kokatha man

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Posted 27 July 2021 - 08:19 PM

Leaving aside the "smoke & mirrors" myths of AS!3 it is inconsequential...sorta like "double stack referencing" but it is true that a sharp image is easier/better to place the MAPs onto. waytogo.gif

 

But after loading & analysing the first capture & setting the MAPs all subsequent captures are just dropped into the pre-existing MAPs arrangement - I hope no-one is resetting them for the subsequent captures..! rofl2.gif bigshock.gif


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#9 dcaponeii

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Posted 27 July 2021 - 08:42 PM

So here is a result from my playing around today.  It's still not perfect but I did discover that in one of the full-chip images today the moon on the lower right hand side of the image is in focus without distortions even though the moons closer to the disk of Jupiter and the shadow have the cruciform distortions.  Maybe the camera is off axis.

 

2021-07-25-0831_8-DWC-L-Jup__M__AS_P5_lapl5_ap258_Drizzle15wAP.jpg

 

This other image is later in the events which had so much distortion as to be a waste of effort.  This is much better.

 

2021-07-25-0857_7-DWC-L-Jup__M__AS_P5_lapl5_ap263_Drizzle15wAP.jpg



#10 Tulloch

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Posted 27 July 2021 - 10:09 PM

Leaving aside the "smoke & mirrors" myths of AS!3 it is inconsequential...sorta like "double stack referencing" but it is true that a sharp image is easier/better to place the MAPs onto. waytogo.gif

 

But after loading & analysing the first capture & setting the MAPs all subsequent captures are just dropped into the pre-existing MAPs arrangement - I hope no-one is resetting them for the subsequent captures..! rofl2.gif bigshock.gif

I always have to reset - field rotation issues again :)



#11 KiwiRay

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Posted 28 July 2021 - 12:23 AM

Right - I always reset for the same reason. Even without field rotation, I can't see that it would hurt anyway - the exact placement shouldn't matter much.


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