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M51-Whirlpool Galaxy

  1. Mar 5, 2012 #1

    Drakkith

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    Hey all. Just finished my best galaxy picture yet, this time of the Whirlpool Galaxy, AKA Messier 51. Enjoy!



    http://img13.imageshack.us/img13/5875/m51colorfinal.jpg [Broken]
     
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Mar 5, 2012 #2
    Wow! What telescope?
     
  4. Mar 5, 2012 #3

    turbo

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    You managed to get a pretty good likeness of that little barred spiral, too (below M51's companion the way your image is oriented).
     
  5. Mar 5, 2012 #4
    Fantastic work. Can you post your equipment and settings?
     
  6. Mar 5, 2012 #5

    Drakkith

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    Scope: Astrotech 8" Ritchey-Chrétien
    Camera: SBIG ST2000XM
    Mount: Orion Atlas

    Approximately 3 hours of exposures for luminance and 30 min each RGB. The exact numbers are hard to pin down, as I've been imaging this over 3 different nights from the 26th of Feb through last night, and had to throw out many sub exposures. Full moon, light pollution, plus a large light dome makes it hard to know which ones to keep. :confused:
     
  7. Mar 5, 2012 #6

    DaveC426913

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    Wow. That is double plus good.
     
  8. Mar 5, 2012 #7

    Andy Resnick

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    awesome! It's been cloudy here for 3 months straight :(
     
  9. Mar 5, 2012 #8

    drizzle

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    Wow! That's great.
     
  10. Mar 5, 2012 #9

    Drakkith

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    Yeah when I finally started on M51, I turned on my mount, and since it saves the last date that you used it, I noticed it said January 29th. The night I started on M51 was February 26th. Freaking terrible weather for almost an entire month. I'd hate to have 3 months of it...
     
  11. Mar 16, 2012 #10

    Borg

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    Great photo Drakkith.

    I really need to get a computerized drive one of these days.
     
  12. Mar 16, 2012 #11

    Drakkith

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    I've got an Atlas EQ-G. It works pretty well for me. My buddy was testing his Atlas out after getting it souped up with new gears and such, in preparation for writing an review in a magazine, and he noticed his new gears were actually worse than the original ones. Not that the new ones were bad, but he jokes that, by chance, he has the most accurate stock Atlas gears in the world.
     
  13. Apr 4, 2012 #12

    Andy Resnick

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    Nowhere near as good, but here's what I have so far: 5 minutes worth of exposure (0.8s at a time), cropped and re-sized, etc. etc.

    http://img20.imageshack.us/img20/1015/m513.jpg [Broken]

    For some reason, the image stacking lowers the overall color saturation. I'm hopeful that at some point I'll be able to pick out a low-surface brightness galaxy located in the lower left area of the image
     
    Last edited by a moderator: May 5, 2017
  14. Apr 11, 2012 #13

    Andy Resnick

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    getting better- 20 minutes total exposure time- cropped and re-sized:

    http://img688.imageshack.us/img688/1779/m51combinedallfiltereds.jpg [Broken]

    and 1:1 crop:

    http://img685.imageshack.us/img685/973/m51combinedallfilteredc.jpg [Broken]

    It's kind of crazy- these images represent 120 GB of data. There are some magnitude 14 and 15 objects visible, but NGC 5229 hasn't appeared yet.
     
    Last edited by a moderator: May 5, 2017
  15. Apr 12, 2012 #14

    Drakkith

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    Andy why are you using 0.8 sec exposures? Those are crazy short.
     
  16. Apr 12, 2012 #15

    DaveC426913

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    Short exposure times mean you don't have to move the camera to compensate for Earth motion. But you take many, many (20 min = 1200) short exposures, then stack them.
     
  17. Apr 12, 2012 #16

    Andy Resnick

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    Don't have a tracking mount.
     
  18. Apr 13, 2012 #17

    Drakkith

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    Ahh, ok.
     
  19. May 15, 2012 #18
    I tried shooting M51 last night as well but like Andy, I don't have a tracking mount. Well, I do, but its not very good and never works the way it should as its under sized, even for my small 80mm scope. Anyway, below is a shot of M51 I took last night using a tripod.

    4x45sec and 6x60sec subs at ISO 3200 ISO using my K-5 with a DA 55-300mm lens
    1z3xzbk.jpg

    and a cropped image...
    2lxujux.png

    BTW, Andy I think you lose color saturation when you stack because the RGB levels need to be significantly lowered in the process. Otherwise when stacking so many images you hit the limits of the color/brightness scale. I always bump up the saturation after stacking and it seems to work ok although it can bring out a lot of noise.
     
  20. May 15, 2012 #19

    Andy Resnick

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    Nice!

    I think I understand what you mean re: color saturation... I'll have to poke around in DeepSkyStacker. Recently tho, I've just been shooting in B&W- I can fit 2x the images on a memory card that way. The lab computer is crunching M53 as we speak, if the weather holds out tonight I'm going to try M3.
     
  21. May 18, 2012 #20

    Andy Resnick

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    I apologize in advance for 'thread creep'- I guess we could start a generic 'astrophotography' thread...

    In any case, it's been an excellent time at my location for seeing deep sky objects- the constellation Virgo is well-placed, Saturn is clearly visible near Spica, and there are *tons* of galaxies and clusters in that region of the sky. Naturally, once I figured out how to stack and post-process images efficiently, I am now taking data faster than the lab computer can handle- call it 3000 frames per night (300GB data per night). Hopefully on Monday I will have some final results- today I prep everything for a batch run over the weekend. I'm posting the full-size images on my blog, here I will only post 1:1 crops of 'things of interest;- for example M53:

    m53_deconvolved.jpg

    and preliminary images of the siamese galaxies- this is a tiny section of (I think) the Virgo supercluster- there are hundreds of galaxies in the total field of view (one of them is upper center-left in the frame), I'm hoping to pull some of them out of the background with the thousands of images I'm stacking this weekend- this was a result of 700 frames (about 10 minutes exposure time, ISO 3200)

    http://img69.imageshack.us/img69/6195/maxtotalnobkg2.jpg [Broken]

    M3 is still chugging along- getting those images was a challenge because the cluster was located directly overhead- if my tripod had a center column I couldn't have gotten the camera vertical enough. In a few weeks the globular cluster in Hercules comes into view, so that should be interesting as well.
     
    Last edited by a moderator: May 6, 2017
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