To all, The effect called irradiation limits the angular size one can distinguish the silouete of an object against a bright background. In the case of the Sun this lower limit on the size is about 1 arcsecond. For Geostationary satellite ranges ( 40,000Km) this means about 200 meters or yards. So maybe just Milstar but not the ASTRA cluster. For the lower NEO's at ranges of 1000KM the lower size limit is 5meters. So I think detail would show on the lacrosses , the Keyholes and maybe HST. I also think that short exposures would be required ( or tracking) to reduce image motion blur to acceptable limits. This consideration comes up when considering the chances of seeing NEO asteroids against the solar disk. Brought up by Duncan Steel at the 1992 National Australian Convention of Amateur Astronomers, and shown to be not a useful technique because the asteroids angular diameter would be too small. Tony Beresford ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Thu Jan 25 2001 - 03:37:48 PST