To add a few tips to Jim Scotti's: If the air is clear/clean, 90 degrees (or more?) away from the Sun the sky is dark enough. In any case, try to find a spot where the Sun is blocked by a house or dense trees. Timing is essential - if I strain my neck more than a few seconds (in daylight only?!) I see many short flashes. For the right spot in the sky I have often used a compass and an adjustable angle finder with a spirit level, well in advance. If you can find a place shadowed from the Sun, where you have a marker near the expected spot, like a TV antenna or a chimney, the corner of a roof , or a tree top, note the place carefully. I have some times used George Roberts' suggestion: On a night in advance, you can use a planetarium program to find a star at the right position, then locate the marker described above. You can find the RA/Decl. of the flare if you use Rob's SkyMap or IridFlar. [Heavens-Above won't show you a star map for daytime flares, but you could convert the az/alt mathematically or using a planetarium program] Then find a reference star at the "same" declination and note the R.A. difference. If the star is at a lower RA, subtract this time diff from the flare time (add if larger). Subtract 23h56m as (many times as) needed. This gives the time you should go out to find your marker. Observer's Location: Bruce MacDonald ( 51.3440°N, 1.9849°W) Local Time: British Summer Time (GMT + 1:00) _______________(Mag.) Flare position Flare _____centre Sun ______________Satellite _____________________Alt.Azimuth Distance ________Mag Alt.Azimuth From flare 04 Apr 18:23:08 -8.1 71° 324° (NW ) _1.6 km (W) __-8.2 12° 264° (W ) 69° Iridium 91 (69 degrees from Sun makes a polarizer possible) 71 deg high makes finding a marker a bit hard, but remember it feels like 90, if you are not lying flat on the ground! With az=324 I have RA=04:18, Dec=+64.8 (SkyMap for flare time) There are no bright stars at convenient hours tonight, alpha UMa is close enough, but at 00:35 local time it will be 5 deg above the flare pos. At 22:45 you have the two stars (mag +4.5/+5.5 five deg. of omi UMA at 08:41, +64.3) there. Note: Heavens-Above has 27373 Iridium 91 SpaceTrack has: 27373 Iridium 90 http://www.io.com/~mmccants/tles/iridium.html has (March 06): 27372 Iridium 91 ? Spare was called Iridium 90 27373 Iridium 90 ? Moving between planes (Oct. 2005) was called I 91 ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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