Re: Unwanted satellite tracks in astrophotos

From: Anthony Ayiomamitis (
Date: Sun Feb 23 2003 - 07:45:34 EST

  • Next message: Peter Wakelin: "SATOBS 2003 February 22"

    > Subject: Unwanted satellite tracks in astrophotos
    > Date: Sat, 22 Feb 2003 15:34:52 -0800
    > From: "Matson, Robert" <>
    > To: "' '" <>
    > Hi All,
    > Regarding (unwanted) satellite tracks in astrophotographs, Tony wrote:
    > > Astronomers using wide field telescopes ( like the UK schimdt at
    > > Siding Spring mountain ) ,have been complaining for 20 years Tom.
    > > There is a particularly bad example published many years ago in
    > > Sky & Telescope that shows 5 trails on one plate. ...
    Hi Rob,
    > What's surprising is that more astrophotographers don't make use
    > of computer programs have existed since the early 1990s (e.g.
    > SkyMap) that completely eliminate the problem.  In a matter of
    > seconds, you can find every satellite that is going to intersect
    > your camera's field of view during the exposure time and plan
    > accordingly.  Suppose you want to take a 1-hour exposure, and
            Imaging around the transit times is probably the only alternative.
    Furthermore, the modus operandi these days is to take multiple exposures of shorter
    duration than fewer of a longer duration. For example, most will take 6x10-min
    rather than 1x60-min.
            There are two primary reasons for this ... most unguided mounts allow
    acceptable exposures which are quite short in duration ... and the second reason is
    indeed the satellite and/or unexpected plane overhead issue.
    > three objects will transit the FOV during that hour.  If shifting
    > the start time of the exposure is not an option, all you have to
    > do is temporarily block your aperture during the few seconds
    > that each satellite will pass through.
           There is a problem here if one is using a guider and/or adaptive-optics unit
    which constantly feed off the guide star.
    > Cheers,
    > Rob
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