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M51 Whirlpool + data

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#1 Sean13

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Posted 11 January 2013 - 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.

Posted Image

Stacked and Calibrated TIFF: https://www.dropbox..../Whirlpool 2...

Zip of all data including calibration frames: https://www.dropbox..../WHIRLPOOL 2...

#2 pfile

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Posted 11 January 2013 - 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.

#3 Sean13

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Posted 11 January 2013 - 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.

#4 Dustin S

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Posted 11 January 2013 - 05:32 PM

This is what I got from your data!

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#5 Sean13

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Posted 11 January 2013 - 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.

#6 shawnhar

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Posted 11 January 2013 - 07:47 PM

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

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#7 pfile

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Posted 11 January 2013 - 08:07 PM

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

#8 Sean13

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Posted 11 January 2013 - 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.

#9 mmalik

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Posted 11 January 2013 - 08:32 PM

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

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#10 Dustin S

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Posted 11 January 2013 - 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.

#11 Sean13

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Posted 12 January 2013 - 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:

Posted Image

#12 stelios_STI

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Posted 12 January 2013 - 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!!!

#13 orlyandico

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Posted 12 January 2013 - 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.

#14 Sean13

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Posted 12 January 2013 - 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.

#15 Dustin S

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Posted 12 January 2013 - 06:35 PM

I like your second process a lot more!

#16 pfile

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Posted 12 January 2013 - 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.

#17 Sean13

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Posted 13 January 2013 - 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.

#18 harry page 1

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Posted 13 January 2013 - 04:23 AM

Hi

Gave it a run through PI :cool:

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

Regards Harry

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#19 proteus5

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Posted 13 January 2013 - 05:13 AM

Here's my shot at it with Startools.

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#20 bouffetout

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Posted 13 January 2013 - 03:15 PM

That's a very good shot dude !

#21 Sean13

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Posted 13 January 2013 - 03:16 PM

Would some of my noise (specifically the outside edges) be what they call Banding Noise? I skipped the step in my processing for banding noise reduction because I didn't think I saw any, but now that I think about it I wouldn't know what it looked like if I did see it, so I have no idea.

#22 Ugmul

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Posted 13 January 2013 - 04:43 PM

If your having trouble with Pixinsight, take a look at Harrys Videos, hes does an amazing job.

Just google, "pixinsight tutorial harry"

He does an amazin job showing the basics, and even with basics you can get some great details out.






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