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Pleiades Stacking vs Equatorial Mount long exposure

Discussion in 'Astrophotography' started by jmax, Oct 10, 2014.

  1. jmax

    jmax Mu-43 Regular

    63
    May 22, 2012
    Hi everyone,
    last weekend I took a picture of the stars. It's a stack of 16 photos taken with the GF1 and P20mm at 15", f1.8, ISO 800. with 16 Darks, Flats and Bias, using Deep Sky Stacker.

    pleyades.
    16 stacks of 15", f1.8, ISO 800

    Compared with another one I took 2 years ago, 256" long exposure taken with a hand made non-motorized equatorial mount,
    _1130391.
    256", f2, ISO 400


    I have to admit that the stack provides better results in terms of sharpness, but long exposure provides a greater number and variety of stars shine and a richest histogram. Here a crop comparison of the Pleiades (levels adjusted):
    compare.

    I assume the risk of errors caused by the manual equatorial mount, maybe a motorized will offer optimal comparison with better sharpness. The next test will be a stacking of 16 long exposure pictures taken with the eq mount :biggrin:

    Advice are really welcome

    Regards
     
  2. RenaudVL

    RenaudVL Mu-43 Veteran

    308
    Mar 21, 2011
    Interesting demonstration,

    As far as I am concerned, nothing beat longer exposure, limited only by tracking accuracy, hight ISO noise and light pollution.

    Then you stack those longer exposed photos with DSS and voilĂ ...
     
  3. PeHa

    PeHa Mu-43 Veteran

    206
    Nov 12, 2013
    Uppsala, Sweden
    Good work using DSS but it clearly shows that stacking several images in DSS will not ackumulate the light of those, it will just use the images to provide one clean image, i.e. 16 images with 15 secs exposure in DSS will have the same exposure level as a single 15 secs exposure, not like a 16x15=240 secs exposure which would look much different, more like your long exposure.

    Your samples clearly shows that. An application that both ackumulates the images and also uses them to clean noise would be nice but I haven't found such an app yet...

    BR//Per