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Astrophotography and Sketching >> CCD Imaging & Processing

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WhitenerJ
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Reged: 02/06/12

Loc: Waxahachie, Texas
First image with QHY8L new
      #5685154 - 02/17/13 12:48 PM Attachment (39 downloads)

Well I have been practicing using my new QHY8L and finally took my first image with it last night. I took a 0.2" shot of the moon using Nebulosity. It looks mostly ok except for some artifacts and jagged edges around the moon. What caused this? I did not see this when doing some test shots on some bright stars.

Jason


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Inverted
sage
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Reged: 01/19/13

Loc: LP Land
Re: First image with QHY8L new [Re: WhitenerJ]
      #5685376 - 02/17/13 02:53 PM

Interesting. Is the L monochrome? Otherwise I would guess some debayering artifact. Could also be a stacking issue I guess. More info on the process could help. I don't think it is really intended for short exposures of bright objects though, so, I'm not sure it is a good indicator anyways. If the electronics aren't optimized for short exposures, I could imagine that could introduce various read artifacts and such, but I don't know much about that so, can't help much more sorry.... Here is a bump at least.

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WhitenerJ
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Reged: 02/06/12

Loc: Waxahachie, Texas
Re: First image with QHY8L new [Re: Inverted]
      #5685381 - 02/17/13 02:55 PM

It's a OSC CCD and not stacked since it was a single frame. Interesting about being optimized. I would assume it could take pics of the moon and DSO's.

Jason


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Mike7Mak
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Reged: 12/07/11

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Re: First image with QHY8L new [Re: WhitenerJ]
      #5685478 - 02/17/13 04:24 PM

It looks like aliasing from low resolution and/or resampling down at 8 bits in processing. The jagged edges are also visible on the crater rims if you zoom in. The Orion 80mm must be somewhere around 3 arcsec/pix with the QHY8L 7.8um pixels. That's not 'high' res but I should think it's enough to give better edges than that. If you converted to 8 bit jpeg before resizing that might do it.

You're capturing in 16 bit fits, yes?


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WhitenerJ
professor emeritus


Reged: 02/06/12

Loc: Waxahachie, Texas
Re: First image with QHY8L new [Re: Mike7Mak]
      #5685487 - 02/17/13 04:29 PM

Quote:

It looks like aliasing from low resolution and/or resampling down at 8 bits in processing. The jagged edges are also visible on the crater rims if you zoom in. The Orion 80mm must be somewhere around 3 arcsec/pix with the QHY8L 7.8um pixels. That's not 'high' res but I should think it's enough to give better edges than that. If you converted to 8 bit jpeg before resizing that might do it.

You're capturing in 16 bit fits, yes?




Yes it was a 16 bit Fit. I actually used Sequence Generator Pro to capture and Nebulosity to process.

Jason


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WhitenerJ
professor emeritus


Reged: 02/06/12

Loc: Waxahachie, Texas
Re: First image with QHY8L new [Re: WhitenerJ]
      #5685842 - 02/17/13 07:55 PM

Re-did the pic tonight using Nebulosity as the capture program. Seems to be smoother now. Not sure what caused the artifacts.

http://tinypic.com/r/jh4pis/6


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David PavlichAdministrator
Transmographied
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Reged: 05/18/05

Loc: Mandeville, LA USA
Re: First image with QHY8L new [Re: WhitenerJ]
      #5686140 - 02/17/13 10:55 PM

It's really not that bad. These cameras were not made for imaging stuff like the Moon and Planets. They're made for long exposures for the more dim things. I just came in from an attempt on the Intergalactic Wanderer...I love that name! I use a QHY8 Pro. I hope to process it tomorrow. What I saw on the screen didn't look all that great, but I won't know 'til I stretch it a bit.

Anyway, you're off to a good start! The camera is working as it should. You might want to take a crack at M42 while Orion is still around.

David


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Mike7Mak
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Reged: 12/07/11

Loc: New York
Re: First image with QHY8L new [Re: WhitenerJ]
      #5686142 - 02/17/13 10:55 PM

A new shot or the same one reprocessed? In any case better, much less color noise as well. Still some aliasing but without seeing the raw fits it's hard to say whether it's just resolution or a processing artifact.

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WhitenerJ
professor emeritus


Reged: 02/06/12

Loc: Waxahachie, Texas
Re: First image with QHY8L [Re: Mike7Mak]
      #5686147 - 02/17/13 10:59 PM

Quote:

A new shot or the same one reprocessed? In any case better, much less color noise as well. Still some aliasing but without seeing the raw fits it's hard to say whether it's just resolution or a processing artifact.




Here is the raw fit file.

https://docs.google.com/file/d/0B1ae8BkkZsmreUh2dGRrRU5PdTg/edit?usp=sharing

Jason


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bill w
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Reged: 03/26/05

Loc: southern california
Re: First image with QHY8L new [Re: WhitenerJ]
      #5686200 - 02/17/13 11:38 PM

needs to be debayered
with one shot color cameras, the image needs to be converted to color
otherwise you will see that strange artifact
can be done with most if not all astro software packages


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Mike7Mak
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Reged: 12/07/11

Loc: New York
Re: First image with QHY8L new [Re: WhitenerJ]
      #5686205 - 02/17/13 11:42 PM

That's some field of view. Plugged the numbers into CCDcalc, fov is 108x162 arcmins, and scale is 3.21 arcsec/pix. There's some aliasing in the raw fits so I'm guessing it is just resolution that debayer makes worse. Plus it's a single frame, a stack would probably smooth out the edges a bit. I've never had the moon that small in a frame so I'm out of my element at this scale.

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WhitenerJ
professor emeritus


Reged: 02/06/12

Loc: Waxahachie, Texas
Re: First image with QHY8L new [Re: Mike7Mak]
      #5686575 - 02/18/13 08:30 AM

Thanks David for the words of encourgment, my next target will be M42.

Mike thanks for looking at the Fit file. Guess I might need a bigger scope to bring out more detail on something like the moon without causing too many artifacts. Looks like I'll stick to stacked DSO's with the QHY8L and get a DSLR maybe for the moon.

Jason


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