A&P An astropic without a telescope

Discussion in 'Lifestyle' started by EWhytsell, Aug 12, 2008.

  1. EWhytsell

    EWhytsell New Member

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    Here's a project I worked on this weekend. It was done using just a 40D with the cheap 75-300mm lens at 300mm F5.6. Its a section of Veil Nebula.
    This is a very low res file. I'm still working on the high res version in PS.
    Its got some problems, but with that lens I'm not gonna get a perfect image its just to tiny for what I was imaging.

    [​IMG]

    Evan
     
  2. Bowzyr

    Bowzyr sup bro

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    That's sick dude... details?
     
  3. QWIKSNK

    QWIKSNK New Member

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    wow, how did you do that?
     
  4. EWhytsell

    EWhytsell New Member

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    Oh forgot to mention the camera was mounted on my mount in place of my telescope for tracking and a shutter release was used to make 1.5minute exposers. I combined 32 of them to get 48 minutes worth of light hitting the sensor.

    In camera noise reduction is turned off so you do it manually by putting the lens cap on and taking a few more pics of the same time length to get a picture of the sensors signal to noise ratio at that particular ambient temp.
    Then you subtract those dark frames from the light frames using software that some nerds made and you get an image.

    Then after hours and hours of processing in PS adjusting levels, curves, reducing all the bad things that happen to pictures when shooting you end up with something you can see.

    BTW the nebula is about 3.5-4 degrees long so you can't see it in a lot of telescopes. You need a very wide field telescope or a large telephoto lens to get a better pic.


    Evan
     
  5. hootpie

    hootpie New Member

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    Puts things in perspective.
     
  6. Hyperite

    Hyperite Vagina Junction OT Supporter

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    welcome to OT and OTAP... looking forward to seeing more of your work :coold:
     
  7. TurkeyChicken

    TurkeyChicken New Member

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    damn dude. I'm impressed :bowdown:
     
  8. EWhytsell

    EWhytsell New Member

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    Thanks, I'm learning daytime photog stuff too, but I suck and am lurking around reading mostly.

    Evan
     
  9. Gvidon

    Gvidon New Member

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    Damn. :eek4:

    :bowdown::bowdown::bowdown:
     
  10. f/2.8L

    f/2.8L New Member

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    Hmm...
     
  11. Yoritomo

    Yoritomo dad's jar chimer

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    My God, It's full of stars...
     
  12. ///Mik3

    ///Mik3 New Member

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    quick question, just wondering cause i don't do this sort of thing. Is there an advantage to doing several 90 sec exposures over just doing one long 48 minute exposure?
     
  13. EWhytsell

    EWhytsell New Member

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    Yes since most of you don't do long exposure work you probably only see a little bit of the signal to noise ratio effect on an image. In a single 48 minute exposure you get a huge amount of heat saturation which causes hot pixels.
    You get 48minutes of light and 48minutes of noise. By doing the 32 1.5min exposures you average out the signal/noise ratio. The more exposures you add in the better you can get the S/N ratio and the sharper and brighter your resulting picture will be. You can do this type of averaging up to about 400-600 exposures. Then the gains become to small.

    There are a few other benefits as well.

    1) In most places in the US you can't get skys dark enough to shoot a very long exposure (say over 6 or 7 minutes using a light pollution filter) before the background starts to wash out the details of the subject.

    2) If shooting the moon or planets doing hundreds of exposures ensures that you get at least a good number of excellent shots in the mix with a whole bunch of shots ruined by atmospheric distortion, airplanes, and other stuff.

    Believe it or not a $40 web cam is the way to go for planetary imaging. I haven't tried it yet, but I guess since its a video camera you can quickly rack up several hundred or even 1000 frames and then stack them.

    Evan
     
  14. Twisted STi

    Twisted STi All wheel or no wheel OT Supporter

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    thats awesome. i'd love to see the high res when youre done with it :bowdown:
     
  15. EWhytsell

    EWhytsell New Member

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    I'm nearly done, but its 218MB's of data and thats after cropping out the part with the serious vignetting. It took my computer hours to run some of the PS filters.

    For some reason at 100% size a lot of the stars show what I think is some light bounce from inside the lens itself so I'll be limited to 16x12 or so for a print size unless I go in and manually touch up each star.

    Evan
     

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