> Subject: Unwanted satellite tracks in astrophotos > Date: Sat, 22 Feb 2003 15:34:52 -0800 > From: "Matson, Robert" <ROBERT.D.MATSON@saic.com> > To: "'SeeSat-L@satobs.org '" <SeeSat-L@satobs.org> > > 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. Anthony. > Cheers, > Rob ----------------------------------------------------------------- To unsubscribe from SeeSat-L, send a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@satobs.org List archived at http://www.satobs.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Sun Feb 23 2003 - 07:55:16 EST