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Re: Optical Tracking?




I found some recent NORAD elements for PCSAT, and plugged them into my
plantarium program. If I can get the rectangular field of view parallel
to the path of the satellite, it looks like it will take 17 seconds
to cross my CCD detector's field of view. I've got 500 pixels of
resolution in that dimension, or about 34 milliseconds per pixel at
that rate. I'm guessing that I'd be luckly to resolve detail smaller than
a couple of pixels, so figure closer to 70 milliseconds of resolution.
This with a 480mm focal length instrument.

If it's spinning much faster than that, then with my longer focal length
instrument (1099mm) it will take about 7 seconds to cross the field 
of 500 pixels.

Hmm.. this might just be doable given sufficiently accurate TLE's so
that the scope can get aimed at the right part of the sky.  My
telescope mount should be able to hack the 20 arc minutes, no problem,
especially since I can verify the position by observing the stars
in the background.

louie
wa3ymh

camera: http://www.starlight-xpress.co.uk/Test/mx5.htm
mount:  http://www.astro-physics.com/products/mounts/900gto/900gto.htm
telescopes:
        http://www.astro-physics.com/products/telescopes/155edfs/155edfs.htm
        http://www.company7.com/televue/telescopes/ranger.html


http://www.astro-physics.com/
> It moves through say 90 degrees of arc in about 2  minutes maybe...
> You should see it witn binoculars, so a viewfinder would work better.
> 
> bob
> 
> On Wed, 3 Oct 2001, Louis A. Mamakos wrote:
> 
> >
> > Bob,
> >
> > I've got a a telescope mount with great positioning accuracy (on the
> > order of 10 arc minutes or so).  What would be helpful is a back-of-the
> > envelope computation of what the apparent motion of the satellite is,
> > say within a 1 degree field of view, and if we'd be likely to see
> > enough blinks during that time to get meaningful measurements.   So,
> > we could part our telescope on a part of the sky, and wait for PCsat
> > to fly through the field, rather than trying to actively track it.
> >
> > I don't recall what the computed apparent magnitude was likely to be; but
> > I suspect that with my 6" f/7 refractor, I ought to be able to see it.
> > Visually, even in my light polluted area, I can go to at least mag 9 or
> > better.
> >
> > Alternatively, if the apparent motion is small enough, I should be able
> > to do a long-exposure CCD integration and see the light come and go.
> > Working backwards, the blinking rate should be computable.  Even with
> > a 70mm f/6.8 scope, giving a much larger field of view, I suspect the
> > CCD camera would be able to image the beacon blinking on and off.
> >
> > I'd be interested in trying something like this, please let me know
> > if you continue to pursue this approach.
> >
> > louie
> > wa3ymh
> >
> 
> de WB4APR@amsat.org, Bob
> 
> ISS-APRS FAQ:       http://www.ew.usna.edu/~bruninga/iss-faq.html
> PCsat Design        http://www.ew.usna.edu/~bruninga/pcsat.html
> CUBESAT Designs     http://www.ew.usna.edu/~bruninga/cubesat.html
> APRS LIVE pages     http://www.ew.usna.edu/~bruninga/aprs.html
> APRS SATELLITES     http://www.ew.usna.edu/~bruninga/astars.html
> MIM/Mic-E/Mic-Lite  http://www.toad.net/~wclement/bruninga/mic-lite.html

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