(See also http://www.satobs.org/iridium.html#flares) First, 'Select' or 'Enter' your coordinates, and bookmark the H-A home page, if you haven't already. www.heavens-above.com/main.asp?lat=41.63&lng=-0.88&alt=188&loc=Zaragoza In addition you can bookmark favourite search pages, like for Iridium 7 days ahead: http://www.heavens-above.com/iridium.asp?lat=41.633& lng=-0.883&alt=188&loc=Zaragoza&TZ=CET&Dur=7 (combine lines!) or even: www.heavens-above.com/iridium.asp?lat=41.63&lng=-0.88&alt=188&loc=Zaragoza Correct coordinates are necessary to catch the brightest flares, because the ones from high in the sky are about 10 km wide only (but can be seen several 100 km off) You are in luck - one -8 magnitude in the morning and two in the evenings this week (UTC+1): 16 Mar 07:13:30 -8 45° 153° (SSE) 1.4 km (E) -8 Iridium 15 ... 19 Mar 20:21:09 -6 57° 139° (SE ) 6.0 km (W) -8 Iridium 63 20 Mar 19:27:25 -8 56° 359° (N ) 2.0 km (E) -8 Iridium 17 Standard info from (above) page is sufficient if you know the direction angles. To find reference stars, either use a star charting program that displays/locates the alt/az given, or note the exact time of a flare, click on the satellite name, then 'Passes'. On the correct pass time, click the date (!). (Unfortunately, Iridium 15 is just two minutes before sunrise, and not listed there; I use Ir63 2005-03-19 as example) Scroll down to the 'Detailed Star Chart' and locate the time (20:21:15 at right edge) If the correct time is outside, click outside the margin to relocate the map. You can get a larger image in the dialog box below, and/or a close-up by clicking on the track, near the flare time. Either way, you find that this flare is midway between Procyon and the Sickle of Leo, above the head of Hydra. Many flares are not listed at H-A: the ones fainter than mag -0; those Iridiums that are in spare orbits, but still functional, and flares from the solar panels (not radio antenna panels=MMA). These will all be predicted by Rob Matson's IridFlar (http://www.satobs.org/programs/flare221.zip), and his SkyMap (http://users2.ev1.net/~mmccants/skymap66/) will show each colour coded (except solar panels) on normal satellite prediction charts. Even without predictions, you can often succeed by looking for the adjacent operational Iridiums at + or - 9.3 minutes, or spare ones in a similar time frame. Sometimes those overtake the operational ones, so they flare in parallell! With a prediction program like IridFlar or SkyMap (or computation) you find the RA and Dec of the flares, which makes it easier to find terrestrial landmarks like a nearby tree- or rooftop hours in advance, which facilitates looking at the right spot (essential for finding daytime flares). Iridium 15 is about 18 degrees right of Altair,slightly below, at 7:13:30 (UTC+1), RA 19:00, Dec.-0.1 Gamma Virginis is at RA 12:42 (and one degree below), so you could locate that at 00:56 to find the right spot (terrestrial). Or five degrees below Procyon, (RA 07:39) at 19:54 (UTC+1). ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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