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Saturn, April 6, RGB and false color - New

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#1 bunyon

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Posted 07 April 2013 - 08:51 PM

I got a new toy and spent the evening playing with it. I noticed at about 12:30 that the seeing was really good so set about imaging Saturn. I'd had the Dob out so it was cool and I was imaging by about 2am, although Saturn was still below 40 degrees. The best seeing was the first set though there are some later ones that aren't bad. If the seeing at 1am had held off two hours, I'd have been in business.

So, here is the first set RGB and IR and to follow a false color set.

This is the best seeing we've had in some time but it clearly wasn't "great". Solidly good to very good at the start then declining quickly. I've determined the "shadow" as I call it is at least somewhat tied to seeing, so perhaps on a very good night it will disappear.

These were enlarged 125%.

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#2 bunyon

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Posted 07 April 2013 - 08:55 PM

Here is a false color set. The seeing dipped dramatically a little before 3am so I played with some filters before going back to RGB. The images aren't great by any means but it gives an interesting peek at how reflectance varies with wavelength.

(RED) Methane Band is an Edmund Scientific 20nm bandpass filter. On right.

(GREEN) 619 is an Omega Filters 620nm filter with 20nm bandpass. Middle.

(BLUE) is an Astrodon UVenus filter. Left.

Each image was run through AS2 with 3x Drizzle.

The false color was resized 120%.

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#3 Kokatha man

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Posted 07 April 2013 - 08:58 PM

Hey Paul - these are great!!! :applause: :applause:

As I've just finished saying to Frank, despite some gloom maybe from the elevation you fellas are starting to crank out some really decent images with more promise ahead....."way to go!" :waytogo:

#4 bunyon

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Posted 07 April 2013 - 09:08 PM

Thanks, Darryl. I'm very happy with the set. As I say, I was playing with a new EQ mount for DSO imaging and noticed the sky had gotten very still. Saturn was only about 25 degrees up when the seeing was best. The seeing wasn't supposed to be so good or I would have been more ready than I was. Fortunately, I had thought to pull the Dob out to cool just in case.

I am convinced that except for those at very high latitudes, it isn't going to be that bad. However, I'm not hopeful of matching you guys down under. On the good nights, though, 40 degrees should be enough.

It was also the first spring night. While it was quite cool, I was seranaded for hours by frogs and owls. Not a bad way to pass the time.

#5 Az Frank

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Posted 07 April 2013 - 09:58 PM

Paul that some great work! Here in Tucson Arizona during the early morning hours we are seranaded by yapping Cayotes!

#6 bunyon

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Posted 07 April 2013 - 10:08 PM

Those are a great sound, too. There isn't anything like sitting under a good sky in the wee hours of the morning.

#7 Kecktastic

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Posted 08 April 2013 - 03:10 AM

Impressive result Paul, particularly like the IR. It is so difficult in variable seeing and I think even more frustrating when it steadies occasionally to reveal really nice detail to then revert to a waving flag or worse.

#8 ToxMan

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Posted 08 April 2013 - 08:01 AM

Nice images, Paul.

#9 bunyon

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Posted 08 April 2013 - 08:17 AM

Thanks, guys. The low altitude and fluctuating seeing is one reason I play with the false color. Gives a bit of a different view (as a photochemist, I like thinking of different slices of the spectrum) and resolution is already fairly low so the result is a little less dependent on seeing. Also, the narrow bandpasses counter atmospheric dispersion somewhat.

Or maybe I'm just screwing around.

Anyway, I thought I could make the false color smoother by using more frames and not drizzling. This version is without drizzle in AS2 and using 95% of the frames in UV and methane band (about 2000 and 2200, respectively). I used 5000 frames with the 619nm image (as opposed to just over 3000 in the first go). I think it came out much nicer.

I'm particularly taken with the methane band image. As I said the first time I imaged Saturn in the methane band, it is a ghostly light on screen. But the rings came out quite sharp this time, which surprised me.

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#10 bunyon

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Posted 08 April 2013 - 08:18 AM

This is an RGB from about 3:30am - an hour and a bit later than the first set above. Not quite as sharp. Red and green were okay but blue was awful. The sets after this don't look so hot.

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#11 bunyon

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Posted 08 April 2013 - 11:10 AM

So I just saw Darryl's negative of one of his whopping good RGB images and it made me wonder...

Here is the inverted version of the false color RGB above. And, yes, now I'm just screwing around. Writer's block.

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#12 sfugardi

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Posted 08 April 2013 - 11:22 AM

Paul, excellent image set! I like the IR-RGB composite. Have you tried R-RGB? The banding detail is very good. The last false color is wild. I'm hoping for decent seeing soon, its been weeks for me. for Thanks for posting

Regards,
Steve

#13 lcd1080

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Posted 08 April 2013 - 11:44 AM

Yes I agree with Steve, the IR-RGB is a stand-out; it shows much more detail than the RGB including a full CD and additional banding detail. Lots of eye candy with the methane band too.

Pete

#14 bunyon

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Posted 08 April 2013 - 04:33 PM

Thanks again, all.

Steve, a RRGB (with all the original channels is attached).

Pete, I actually re-did the IR - I have never quite pulled out a good hint of Encke gap and wondered if it might be processing. As it happens, I was able to get a nice gap on the ansae - not all the way around. I used LR deconvolution and a smaller PSV (with more iterations). The gap comes at the cost of noise, unfortunately. I'll keep plugging away.

In addition to the RRGB I made for Steve, I've put the new IR and a new IR-RGB using that channel (and the other originals).

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#15 Mike Phillips

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Posted 08 April 2013 - 06:37 PM

Writers block! LOL!
I vote IR-RGB, which I normally don't, but ever so slightly too much on the CD sharpening for the RRGB...
I think it's time to up the focal length a tad bit! I've been too struck with DSO's with the poor weather and new moon, I've been ignoring poor Saturn!

nice Paul J!

Mike

#16 Mitchell Duke

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Posted 08 April 2013 - 07:27 PM

Looks great Paul, and wow what a variety of data you have there.

#17 bunyon

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Posted 11 April 2013 - 04:00 PM

Thanks. I just purchased Topaz denoise after having tried them out several times. I didn't like how it worked with Jupiter but I've been having very noisy Saturns. And I really like Topaz on DSOs. So, what's a few more dollars?

Anyway, here is the original IR-RGB (from way back up top) denoised with Topaz. And resized 200%

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#18 Space Cowboy

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Posted 12 April 2013 - 02:55 AM

Looks like someone has been having fun! Cracking selection of images Paul!

#19 tjensen

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Posted 12 April 2013 - 11:07 AM

Nice ones Paul. Have you tried doing L-RGBs?

#20 CPellier

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Posted 13 April 2013 - 02:04 AM

Good work Paul. Especially the CH4 is good, and Saturn in CH4 is not easy !
The problems with the IR-RGB and RRGB processings is that the details are false (look how the belts change, some have even disappeared). The only way to reproduce the real belts with their colours is RGB or LRGB.






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