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Astrophotography and Sketching >> DSLR & Digital Camera Astro Imaging & Processing

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Sean13
sage


Reged: 11/17/12

Loc: North Platte, Nebraska
M51 Whirlpool + data
      #5617534 - 01/11/13 04:15 PM

This is my first real photograph with my setup. I know I have alot to learn on processing, and I'm trying to learn PixInsight on the trial but its proving to be more of a learning mountain then a learning curve. I'm sure someone here can do a far far better job then I, so I'm going to go ahead and post the stacked and calibrated tiff file, as well as the whole package of all the data if you feel the desire to stack it yourself.

Taken in the AM hours of 1/9/13 from my driveway in Nebraska
8x 15min subs (took 10, threw out 2)
Captured with Backyard EOS, stacked with DSS, and processed with PixInsight. All details on equipment in sig below.



Stacked and Calibrated TIFF: https://www.dropbox.com/sh/7c9dj9wuods30wt/0fXbf9238t/Astropics/Whirlpool%202...

Zip of all data including calibration frames: https://www.dropbox.com/sh/7c9dj9wuods30wt/bBTJ3mYucs/Astropics/WHIRLPOOL%202...


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pfile
Post Laureate


Reged: 06/14/09

Re: M51 Whirlpool + data new [Re: Sean13]
      #5617538 - 01/11/13 04:19 PM

actually i think your processing is pretty good. the data looks to me to have a lot of trailing/guiding error and so it will be difficult to get a really sharp image like that.

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Sean13
sage


Reged: 11/17/12

Loc: North Platte, Nebraska
Re: M51 Whirlpool + data new [Re: pfile]
      #5617551 - 01/11/13 04:23 PM

Yea I do have a bit of trailing. I forgot to enable dithering while taking the pictures, and I some problems lead to not being able to do a proper polar alignment. All I was going off of is my polar alignment scope on the CG-5 and its not all that accurate, so I was having a bit of dec drift all night long.

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Dustin S
sage


Reged: 10/27/11

Loc: Michigan
Re: M51 Whirlpool + data new [Re: Sean13]
      #5617630 - 01/11/13 05:32 PM Attachment (31 downloads)

This is what I got from your data!

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Sean13
sage


Reged: 11/17/12

Loc: North Platte, Nebraska
Re: M51 Whirlpool + data new [Re: Dustin S]
      #5617731 - 01/11/13 06:26 PM

Very nice, coloration looks a ton better then mine, and keeping the image at its full size helps minimize the trailing. What program did you use to do this? Looks 100x better then mine, but hey it was my very first time with PixInsight.

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shawnhar
Post Laureate
*****

Reged: 06/25/10

Loc: Knoxville, TN
Re: M51 Whirlpool + data new [Re: Sean13]
      #5617876 - 01/11/13 07:47 PM Attachment (19 downloads)

Man that is SOOOOOO much better than my attempt!
I gave the data a go in StarTools:


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pfile
Post Laureate


Reged: 06/14/09

Re: M51 Whirlpool + data new [Re: shawnhar]
      #5617915 - 01/11/13 08:07 PM

Did you try ColorCalibration in PI? that should get you pretty close to the right color.

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Sean13
sage


Reged: 11/17/12

Loc: North Platte, Nebraska
Re: M51 Whirlpool + data new [Re: pfile]
      #5617925 - 01/11/13 08:11 PM

I did, but I'm afraid I messed with the individual color curves a bit to much trying to bring out the red lacking by my unmodified camera, then I was like hey this blue looks pretty too and by the time I was done it was a bit overdone compared to others now. I'm going to give it another go in PI and see if I can come up with a comparable color.

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mmalik
Post Laureate
*****

Reged: 01/13/12

Loc: USA
Re: M51 Whirlpool + data new [Re: Sean13]
      #5617958 - 01/11/13 08:32 PM Attachment (21 downloads)

My processing of your data...; refine your tracking and you are all set. My attempt here....Thx

Re-Processing Workflow: (Instructions here...)
•RAW file Processing in ImagesPlus 5.0
•Align TSR/Combine/Crop in ImagesPlus 5.0
•Digital Development in ImagesPlus 5.0
•Multi Point Flatten Background-Planar in ImagesPlus 5.0
•Multiresolution Smooth-Sharpen (Finest/Fine 30/15) in ImagesPlus 5.0
•Geometric Transform/Scale (Factor 0.4) in ImagesPlus 5.0
•Smoothing in ImagesPlus 5.0
•Saturation (Block), and 'Noise Reduction' in Photoshop Extended CS6
•Star Size and Halo Reduction in ImagesPlus 5.0
•Hue-Saturation-Luminance in ImagesPlus 5.0
•Curves, Brightness/Contrast, Saturation, and 'Noise Reduction' in Photoshop Extended CS6

Edited by mmalik (01/11/13 08:38 PM)


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Dustin S
sage


Reged: 10/27/11

Loc: Michigan
Re: M51 Whirlpool + data new [Re: mmalik]
      #5618022 - 01/11/13 09:07 PM

I took your fully calibrated image into CS6, basically i just used curves and levels, that's all. I used levels in lab color once also.

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Sean13
sage


Reged: 11/17/12

Loc: North Platte, Nebraska
Re: M51 Whirlpool + data new [Re: Dustin S]
      #5618444 - 01/12/13 04:20 AM

Redid it aiming for a little better color and leaving the image large to reduce the appearance of trails. Here's my updated attempt:



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stelios_STI
member


Reged: 04/23/12

Loc: Greece
Re: M51 Whirlpool + data new [Re: Sean13]
      #5618469 - 01/12/13 05:12 AM

very nice try, but i think your 15min subs did'n work well for your guiding and the noise. the noise is too mutch.
i think if you take more subs of 8-10 minutes you get better resault.
i forgot to say that the detail on the galaxy is VERY good!!!


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orlyandico
Post Laureate
*****

Reged: 08/10/09

Loc: Singapore
Re: M51 Whirlpool + data new [Re: stelios_STI]
      #5618895 - 01/12/13 11:41 AM

you can use Fitswork to remove the trailing. as long as its due to declination drift and hence all in one direction.

if you have field rotation though... that's another story.


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Sean13
sage


Reged: 11/17/12

Loc: North Platte, Nebraska
Re: M51 Whirlpool + data new [Re: orlyandico]
      #5619067 - 01/12/13 01:24 PM

Pretty sure it is only dec drift and no field rotation. I will have to give that a try, thanks!

Yea I wasn't really sure on exposure time. I don't fully understand how I can tell when I've captured all the data I can possibly capture and should end the exposure, so I just guessed. I've always assumed longer is better, but I guess that isn't always the case.


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Dustin S
sage


Reged: 10/27/11

Loc: Michigan
Re: M51 Whirlpool + data new [Re: Sean13]
      #5619615 - 01/12/13 06:35 PM

I like your second process a lot more!

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pfile
Post Laureate


Reged: 06/14/09

Re: M51 Whirlpool + data new [Re: Dustin S]
      #5619990 - 01/12/13 11:14 PM

on the 2nd processing, i'd maybe do some ACDNR to the chrominance channel either before or after the curves. the red channel is a little hot with noise.

the whole subexposure length thing comes up again and again. the bottom line is that you just need to expose long enough to get the skyglow to overwhelm the read noise of the camera. for a canon DSLR the rule of thumb is to get the histogram hump's left edge 20-30% of the way across the back of camera display, and you are there.

exposing longer won't kill you (until you saturate the stars of course) but from a mathematical perspective exposing longer won't really help with the so-called 'stacking efficiency'. once you've reached the "skyfog limit"* you're there. using the shortest sub you can get away with = less trailing, fewer subs lost to airplanes, etc.


* this term confuses people but what it means is that your image quality will not be limited by the read noise of the camera but rather by the limiting magnitude of your local skies. if you expose shorter than the skyfog limit, then the light from the faintest stars/objects in your image is destroyed by the read noise - essentially overwritten as the image is read off the CCD. getting to the skyfog limit means that objects dimmer than the sky brightness are simply lost in the sky glow, rather than to camera artifacts.


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Sean13
sage


Reged: 11/17/12

Loc: North Platte, Nebraska
Re: M51 Whirlpool + data new [Re: pfile]
      #5620101 - 01/13/13 01:26 AM

Will do. One of my last steps was ACDNR, but I think I messed with my curves one last time after the ACDNR and maybe brought back some of the noise. The reason there is so much noise still is because of my bad skills at masking, I think my structure mask was a little stretched and grabbed a little more then just the structure. Its been one heck of a learning processes thats for sure.

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harry page 1
super member


Reged: 07/25/09

Re: M51 Whirlpool + data new [Re: Sean13]
      #5620170 - 01/13/13 04:23 AM Attachment (8 downloads)

Hi

Gave it a run through PI

As you say a lot of noise , but still some Data to work with

Regards Harry


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proteus5
scholastic sledgehammer
*****

Reged: 06/24/10

Loc: Southern New Jersey
Re: M51 Whirlpool + data new [Re: harry page 1]
      #5620191 - 01/13/13 05:13 AM Attachment (7 downloads)

Here's my shot at it with Startools.

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bouffetout
scholastic sledgehammer


Reged: 11/21/12

Loc: Canada
Re: M51 Whirlpool + data new [Re: proteus5]
      #5621038 - 01/13/13 03:15 PM

That's a very good shot dude !

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