Saturn Occultation in nice seeing, a.k.a. here comes the big rock!

[andyc]

I had decent conditons for the occultation on the 12th. I recorded IR through disappearance, and have made a 2min animated sequence while Saturn was being hidden by the Moon. Some hills on the edge of the Moon are silhouetted against Saturn, and if you look closely, Tethys and Dione are barely visible to the left of Saturn. There's a few individual frames below.

It's too large for IIS, so view the animation at this link (https://photos.app.goo.gl/v5omh1p15HdFQkAj8)

Each frame is 1000 stacked video frames, overlapping (1-1000,500-1500,1000-2000 etc) to generate a smoother sequence across about 14,000 total frames. C14 at f/11.

I made a 2-frame composition with a properly-exposed Moon from a minute after disappearance

[multiweb]

:eyepop: That's awesome. So sharp. Love the details. :thumbsup::thumbsup::thumbsup:

[Atmos]

Saturn photobombing the moon again... Sigh.... :lol:

[cometcatcher]

That's excellent. I completely forgot about it.

[redbeard]

Really really good! Best I've seen. :thumbsup:

[Saturnine]

Very well done once again Andy, captured the occultation nicely.

[multiweb]

Looking at this again this morning on my PC bigger screen and the details are outstanding. Can you elaborate on the gear and settings/ I gathered that to be able to stack the planet and the moon limb from the same video you must have been shooting at a very fast frame rate? Did you barlow or native FL. That looks like over 4m FL.

[Tinderboxsky]

Fabulous result Andy. I think I follow how you have achieved this, but am also very interested in the settings you used.

[andyc]

Thanks everyone for the kind comments.
Marc and Steve, sure, I'm happy to elaborate. It was my usual C14 & ASI290MM set-up, but with no Barlow in place (the FoV with the Barlow is tiny), so about 4m f.l. I recorded using ~1300x950 pixels, most of the chip, but that was only because I barely got set up in time and that was how it was set (too much messing around with other options)!

Capture was 88fps, 277 gain - this exposed Saturn pretty well, but overexposed the Moon. I had Firecapture take continuous sets of 45s IR videos (4000 frames each), but again that was because I was still using old settings. Though it was useful to make each video less huge (they were still each 4.5GB).

After the rush of capture, processing wasn't so bad :work: Obviously the moving Moon was going to be a problem, so I used PIPP to divide the videos into the overlapping 1000 frame blocks, each covering ~11s. On Autostakkert I set for 'surface' image stabilisation, placing the anchor over the partially-hidden Saturn (the 'planet's one doesn't work because the Moon is too bright). Once through the 'Analyse' step, I set some alignment points only on the planet, and stacked 60% of the frames, before sharpening in Registax. I did not expect them to come out anything like as well as this! With the gap between planet and overexposed Moon, I could have placed some chunky alignment points on the Moon to get that sharper (even though overexposed), but I'd processed too many of the individual blocks before I thought of that :P

[Tinderboxsky]

Thank you for the background info Andy.
Yes, it is very easy to be caught short of time when setting up. When up close, Lunar occultations happen in a rush. I have been caught out a few times.

[bigjoe]

What you did was not easy ..well thought out Andy.
Bigjoe.

[multiweb]

Thanks for all the info Andy. :thumbsup:
One thing I don't know how to do in AS!3 is to resize the green image stabilization anchor window. Also how do you restrict the alignment points to that area in automatic mode? I find it really annoying to have to deselected all the ones you don't want one at a time. You can't even drag a selection to remove them. And finally how do you get such a high capture frame rate? You're on USB3?

[andyc]

Stabilisation anchor - I don't think you can resize it, I have a feeling it is based on a fraction of your overall frame size. I was lucky that in my 1000-frame PIPP videos (which I think I cropped slightly , missed that part in info below), the stabilisation anchor was similar to the size of Saturn.
I didn't use automatic addition of alignment points for this (I do for regular planetary captures, with a few tweaks). I manually placed the points for each frame, which made sure that all the alignment was only on Saturn. [Although that's where I could have placed a few bigger alignment boxes on the moon's edge for a slightly cleaner overexposed Moon]

[multiweb]

Cool. I see now how you've positioned your points on Saturn. I had a lot less and in different positions. I tried to do a few manually but the resulting alignment was a shocker so I left it to automatic.

[Dennis]

Excellent views Andy, nicely captured and processed.:):thumbsup:

Once it starts, it seems like there is little time to think as I stood transfixed by the unfolding event and found it difficult to pull myself away and think about tweaking settings.

I found that egress produced a noticeably sharper Saturn, as it was at a greater altitude than ingress.

Cheers

Dennis

[Retrograde]

Great images and animation Andy - excellent detail. :thumbsup: