Re: camcorder tracking of Mir/STS

From: Astronomy Ireland <>
Date: Tue, 6 Jun 1995 20:02:45 -0400

Robert Preston <> wrote:
> David, I don't know a formula but it's a trivial calculation from
> the orbital inclination and RAAN figures in the TLE. Just subtract the
> relevant angles, using your latitude. It's elementary solid geometry.

Observer's latitude should have nothing to dowith it surely?
I'm not that good at "solid geometry" or spherical trigonometry but
a quick bit of doodling led me to the conclusion that:
the pole of a satellite's orbit is at
  declination=90-inclination degrees,
  R.A.=R.A.Ascending Node - 6 hours.
Does that sound right?
I note RAAN seems to be decreasing at about 5.0deg/day. Why? Drag?
On June 7.07 UT the pole would thus be near ra=7h 54m,dec=38.3deg,
7.5 deg. northeast of the star Castor, 4 deg above my north horizon.
Such low altitude will only allow rough alignment, if formula right.
Comments welcomed.

I'm using a super polaris equatorial mount that can be tilted from 0
deg latitude to 90 degrees. It's all I've got with nice slow motion
controls. That's the only reason I'm using it. I'm not saying it's
ideal. Though I expect good results. Mir is currently making morning
passes as seen from Ireland. I'll try the formula next time it's clear!

David Moore BSc FRAS, Editor of "Astronomy & Space" magazine.
( Chairman, Astronomy Ireland, P.O.Box 2888, Dublin 1.
Tel: +353-1-459 8883. Fax: +353-1-459 9933.
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Received on Tue Jun 06 1995 - 20:42:26 UTC

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