transits

Alphonse Pouplier (Alphonse.pouplier@ping.be)
Thu, 25 Jul 1996 23:51:51 +0200 (MET DST)

Rob MATSON wrote:
>I wonder if there are any Seesaters out there with the equipment necessary to
>do solar observations?  More specifically, an 8" scope (or larger) with a
>full-aperture solar filter and an integrated video recorder.  The goal,
>naturally, would be to capture a large satellite doing a solar transit.

When an artificial satellite is passing between the Sun and an observer, it's
easyer to see it (in black on white) than to see it (in white on black) during
the night.

I made a program to predict such "transits".

Here are the principles of that program:

- I can operate a search for 100 satellites at once.
  I select those having,
  1) a sufficient dimension,
  2) a good stability,
  3) an interresting distance.
- I give the coordinates of the place.
- I give the instant from which the search has to start.
- I give the duration of the period to search for.
- I eliminate the uninterresting hours in order to speed the progress.
- The scanning is fast for
  - eliminated hours
  - Sun not risen
  - satellite at more than 6 deg. from the center of the Sun.
  else, scanning at a tenth of a second.
- I ask to get every tenth of a second the instants when the satellite is at
  less than n deg. of the center of the Sun
  (n can be from .25 deg., satellite in principle in the Sun, to 6 deg., for
satellites
  having an uncertain orbit like MIR)

My friend Jean BOURGEOIS could see already some satellites with such
predictions. We hope to record on video tape a transit of MIR.

 Here is the storry: Jean BOURGEOIS is a very serious and well known observer.
 On october 10 1994 he phoned me and said: "Alphonse I was observing the sun a
 few minutes ago and I'm sure a satellite passed across. Can you tell me which
 one it was in order to confirm it to myselve?" He said he could notice some
 shapes and rotations...!
 I couldn't identify the satellite he saw but it gave me the idea to try to
 predict some such transits. Jean was very interrested and its him who told me
 that it's easyer to see shapes in black-on-bright than in bright-on-black.
 I'm not an observer at all. He is experienced and well equipped.
 I could predict a transit for his observation place and a geostationnary
 satellite. That is the easiest to predict but I thought impossible to be seen!
 It was MOP-2. And Jean could see it ! ...
 Jean is equipped for recording on video tape.

My pleasure, avec plaisir,  Alphonse
alphonse.pouplier@ping.be
http://www.ping.be/~ping5861
http://ourworld.compuserve.com/homepages/ALPHONSE