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BKBrown
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Reged: 08/23/09

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ASI120mc Saturn on 6/21/13 new
      #5937058 - 06/23/13 08:24 PM Attachment (259 downloads)

Friday night was pretty decent so I did a bit of imaging. This shot was acquired through the C11 Edge HD, TV 2x Barlow, and ASI120mc w/ Baader UV/IR cut filter. I stepped up from the Siebert 1.75X Barlow to see how much of a difference in scale I would get , and tried a few other things as well. My settings were as follows: Gain - 100, Gamma - 60, and Exposure (ms) - 19/52 fps nominal. I normally leave the Gain at the default 50, but 60 gave me a brighter image and does not seem to have introduced excessive noise, next time I'll try to push it even higher to get a better frame rate and 50%+ histogram in the red. Anybody else out there tinkering with settings who might like to chime in? Looks like I got a decent NPH and some belt details, I'll be out again tonight giving it a try...

Clear Skies,
Brian


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Mitchell Duke
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Re: ASI120mc Saturn on 6/21/13 new [Re: BKBrown]
      #5937088 - 06/23/13 08:44 PM

Brian,
The shot looks great, try setting gamma to the default setting of 50, and brightness to 0.


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BKBrown
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Re: ASI120mc Saturn on 6/21/13 new [Re: Mitchell Duke]
      #5937124 - 06/23/13 09:06 PM

Quote:

Brian,
The shot looks great, try setting gamma to the default setting of 50, and brightness to 0.




Thanks Mitchell! I have been shooting with the gamma 50 and have been having trouble keeping the frame rates up and the red histogram at just above 50. Pushing the gamma to 60 let me shoot with a frame rate of 53 fps vice the mid 40s I was getting, the red and green histos were at and above 50. Do you think I'm picking up too much additional noise?

Clear Skies,
Brian


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Kokatha man
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Reged: 09/13/09

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Re: ASI120mc Saturn on 6/21/13 new [Re: Mitchell Duke]
      #5937128 - 06/23/13 09:07 PM

That's a pretty nice image outcome Brian.

The gamma setting for the ASI cams is recommended to stay at 50 as you'd know anyway, and an old mantra was that raising the gamma a bit in capture wasn't a bad thing, but tbh I've never done any capture trials to determine the truth of that matter: I usually drop the gamma value in post-processing to "0.9" so if you do something similar maybe you could try lowering it even more.....on my screen your image looks like this might be worthwhile but at any rate you caught a very good image regardless..!


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BKBrown
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Re: ASI120mc Saturn on 6/21/13 new [Re: Kokatha man]
      #5937148 - 06/23/13 09:18 PM

Thanks Darryl. I also tend to adjust the gamma down in post processing and did that with this image. Expect I'll be experimenting with this data for a while since I haven't had a lot to work with this season. Cheers!

Clear Skies,
Brian


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zAmbonii
Carpal Tunnel


Reged: 01/19/08

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Re: ASI120mc Saturn on 6/21/13 new [Re: BKBrown]
      #5937162 - 06/23/13 09:29 PM

In this thread Smitty had the gamma cranked to 70.

I'm not really sure if noise is really the problem with cranking the gamma, but with my old webcam it would introduce onion skinning in the final image. But it may not really be a problem with the ASI cameras. If you look later on in that thread linked above, he did go back to gamma = 50, and you can see a difference (the planet itself looks more round).

I think with increasing the gamma you are sorta compressing the color values towards the higher range and an uncorrected image will look flat. Like Darryl said above, you can compensate for it by bringing the gamma back down in post processing, but it may not equal the result if the gamma = 50....but who knows, I don't think that anyone has experimented with it before to see how it looks.

I'm thinking of dragging the scope out in a few. There are T-storms that are threatening us from the South so it may be a washout, but I may give it a try with varying gain in captures and then correcting in post processing. We'll see how it goes.


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hopskipson
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Reged: 06/24/10

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Re: ASI120mc Saturn on 6/21/13 new [Re: zAmbonii]
      #5937292 - 06/23/13 11:21 PM

Not an expert, but that image is excellent!

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wenjha
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Reged: 09/24/08

Loc: SuZhou China
Re: ASI120mc Saturn on 6/21/13 new [Re: hopskipson]
      #5937446 - 06/24/13 03:12 AM

Yes,Darryl and zAmbonii is correct about the gamma setting.
wrong use of gamma will cause onion ring.
60 actually won't cause that. but 50 is the recommended setting.
well done Anyway!


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lcd1080
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Reged: 06/03/10

Loc: Maryland, USA
Re: ASI120mc Saturn on 6/21/13 new [Re: wenjha]
      #5937709 - 06/24/13 10:15 AM

Looks like a fine late season Saturn Brian, resolving the NPH and CD across the globe are both heroic acts in the North 55 days past opposition.

Pete

Edited by lcd1080 (06/24/13 10:52 AM)


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sfugardi
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Re: ASI120mc Saturn on 6/21/13 new [Re: lcd1080]
      #5937910 - 06/24/13 12:09 PM

Brian, excellent image especially this late in the season! Color and details look very natural. Congradulations on this beauty and thanks for posting it

Regards,
Steve


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BKBrown
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Re: ASI120mc Saturn on 6/21/13 new [Re: sfugardi]
      #5938464 - 06/24/13 05:59 PM

Thanks zA, James, Sam, Pete, and Steve It's been a tough Saturn apparition but the new ZWO cams have definitely been a high point. I am looking forward to trying them out on Jupiter before too long...

Clear Skies,
Brian


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leviathan
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Reged: 11/29/11

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Re: ASI120mc Saturn on 6/21/13 new [Re: BKBrown]
      #5939072 - 06/25/13 02:09 AM Attachment (44 downloads)

Looks a bit under corrected in colors. I've slightly changed it, hope you don't mind:

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Baron
sage


Reged: 11/23/12

Loc: Rome, Italy
Re: ASI120mc Saturn on 6/21/13 new [Re: leviathan]
      #5940176 - 06/25/13 05:27 PM

Nice image!

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BKBrown
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Re: ASI120mc Saturn on 6/21/13 new [Re: leviathan]
      #5940306 - 06/25/13 07:07 PM

No, I don't mind ...just don't know what you mean by "under corrected in colors" I think the overall effect is largely dependent on individual monitors, and most folks do not calibrate theirs regularly.

Clear Skies,
Brian


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BKBrown
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Re: ASI120mc Saturn on 6/21/13 new [Re: Baron]
      #5940311 - 06/25/13 07:08 PM

Thanks Paolo

Clear Skies,
Brian


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RedLionNJ
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Reged: 12/29/09

Loc: Red Lion, NJ, USA
Re: ASI120mc Saturn on 6/21/13 new [Re: BKBrown]
      #5941324 - 06/26/13 11:53 AM

Brian - that is one of the very, very few ASI120MC images I've seen where the colors don't look "flat". Whatever you're doing with the settings (perhaps in post-processing, too), you're doing it very right!

Most excellent.

Grant


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semmyboy
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Reged: 05/13/13

Loc: Italy Rome
Re: ASI120mc Saturn on 6/21/13 new [Re: RedLionNJ]
      #5941336 - 06/26/13 12:04 PM

Wow!

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BKBrown
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Re: ASI120mc Saturn on 6/21/13 new [Re: semmyboy]
      #5942308 - 06/26/13 11:14 PM

Thanks Grant and semmyboy
Grant - I find the color rendering with the ASI120mc to be a bit flat. The color is being picked up but it is somehow suppressed...at least to my eye. In PS CS4 I have been increasing (slightly) the saturation and then I fidget with the vibrance until it gets to where I like it. Understanding this cool new camera is still a "work in progress" for me...

Clear Skies,
Brian


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azure1961p
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Re: ASI120mc Saturn on 6/21/13 [Re: BKBrown]
      #5942372 - 06/27/13 12:10 AM

Very impressive image!!!! I enjoy following your work and through different apertures.

Pete


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BKBrown
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Re: ASI120mc Saturn on 6/21/13 new [Re: azure1961p]
      #5946786 - 06/29/13 03:32 PM

Thanks Pete!

Clear Skies,
Brian


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