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Who knows? - Hiding in my Jupiter challenges were some good Saturns

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#1 dcaponeii

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Posted 26 July 2021 - 02:11 PM

Still not rising to contemporary professional standards the images I captured of Saturn on 7/25/21 are among the best I've ever achieved.  Still a bit wonky on color correction (haze and smoke are challenging R6 RGB balance I guess) but really pretty good compared to my previous efforts.  I was processing them trying to figured out exactly when my collimation/astigmatism issues arose the other morning.  Figured they'd be full of those gross Cassini Division pretzels I've come to expect.

 

2021-07-25-0738_5-DWC-L-Sat__M__AS_P1_lapl5_ap158_Drizzle15wdrAP.jpg


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#2 RedLionNJ

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Posted 26 July 2021 - 05:43 PM

I think we may have been here before ...  Look at the rings near the ansae. They are far from symmetrical, with the Cassini division being almost reasonable-looking on the left side and almost invisible on the right side. This can be the result of mediocre seeing, but it can also result from a poor selection of APs during alignment and stacking.  If I think I have decent Saturn data, I'll make quite a few attempts at stacking until I get ansae which are symmetrical in appearance with a crisp Cassini division.  When seeing is particularly good, you might even capture an indication of the Encke minima outside of the Cassini division. Too many people jump to the conclusion they were successful in recording the "Encke gap" when in fact, all they have is an artifact from poor deconvolution.  You're not at that point yet. But watch out when you get there and be aware.

 

Honestly, it's been good to see your progression over the last few months - you ARE coming along.


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#3 dcaponeii

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Posted 26 July 2021 - 05:51 PM

I think we may have been here before ... Look at the rings near the ansae. They are far from symmetrical, with the Cassini division being almost reasonable-looking on the left side and almost invisible on the right side. This can be the result of mediocre seeing, but it can also result from a poor selection of APs during alignment and stacking. If I think I have decent Saturn data, I'll make quite a few attempts at stacking until I get ansae which are symmetrical in appearance with a crisp Cassini division. When seeing is particularly good, you might even capture an indication of the Encke minima outside of the Cassini division. Too many people jump to the conclusion they were successful in recording the "Encke gap" when in fact, all they have is an artifact from poor deconvolution. You're not at that point yet. But watch out when you get there and be aware.

Honestly, it's been good to see your progression over the last few months - you ARE coming along.


Thanks for the feedback and the positive encouragement. Until these half-decent results do not come purely by accident I’ll not be too satisfied. I take it from your comments that you’re using manual placement of AP’s around the ring as Daryl describes? I’ll have to try that. My recent results, while using much smaller AP’s (size 30 multi scale) I’ve been allowing AS!3 to place them for me.
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#4 Kokatha man

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Posted 26 July 2021 - 10:07 PM

<"I take it from your comments that you’re using manual placement of AP’s around the ring as Daryl describes? I’ll have to try that. My recent results, while using much smaller AP’s (size 30 multi scale) I’ve been allowing AS!3 to place them for me.">

 

...just on this & your comments in your other thread, let's hope you get on top of all this soon, though there should still be a lot of imaging opportunities in both planets' apparitions...the comments I've quoted here are a "sometimes" cure for a split Cassini Division at the ansae where a particular type of nasty "vibrating" seeing can induce said: there are other times when it is due to other problems - but placing a ring of small MAPs along the rings can help some of the time - & other times not!

 

Being an old dinosaur I always manually apply the MAPs boxes, suspicious of auto-placement...although I'm sure many folks employ auto without any problems. wink.gif

 

At any rate, from our conversation I felt it was worthwhile to elaborate on the collimation situation with you - I hope that astigmatism isn't an issue as I understand that in SCT's this is something incurable - fingerscrossed.gif

 

But I'm sure you'll get to the bottom of it all! waytogo.gif


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