Occultation event with (1437) Diomedes, event index number 3636
Regions able to see the event: SAmericaN,SAmericaS
Geocentric closest approach at 2026/04/15 00:56:12 UTC
J2000 position of star is 13:10:38.8 -33:32:26
Equinox of date position of star is 13:12:06.8 -33:40:48
Star is 137 degrees from the moon. Moon is 8% illuminated.
Stellar brightness G=14.5, apparent brightess of occulting body is G=13.2
Use an exposure time of 0.80 seconds with the standard RECON-QHY system.
SNR of 9.8 per integration for unocculted signal
Expected flux drop is 24% with SNR of 2.4 for the occulted depth (per occulted point)
Apparent velocity is 17.1 km/sec on the sky relative to the star, or, 19.2 arcsec/hr.
Position angle of asteroid motion is 106.4 degrees
The recommended exposure time corresponds to 13.7 km per image.
The 1-sigma error in the time of the event is 1.5 seconds.
The 1-sigma cross-track error in the shadow position is 24.3 km.
The sky-plane scale is 3205.6 km/arcsec.
Diameter estimates:
140.6 km assuming a 5% albedo, maximum of 8.2 sec for a central chord
57.4 km assuming a 30% albedo, maximum of 3.4 sec for a central chord
Cross-track diameter of 117.8 km used for deployment plan.
Star training set for 1437_Diomedes, (2026/04/15 00:56UT) Object RA Dec mag sep mel Spica 13:26:34.9 -11:17:52 1.0 22.63 149 Iot Cen 13:22:05.0 -36:51:00 2.8 3.77 134 PPM 290865 13:02:30.1 -33:45:54 6.3 2.00 139 PPM 291027 13:10:28.6 -33:38:28 7.4 0.34 138 PPM 291067 13:12:23.1 -33:51:42 9.9 0.19 137 1437_Diomedes 13:12:06.8 -33:40:48 13.2 137 Positions are for equinox of date
Star training set for 1437_Diomedes, (2026/04/15 00:56UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 22.63 149 Iot Cen 13:20:35.1 -36:42:46 2.8 3.77 134 PPM 290865 13:01:03.1 -33:37:26 6.3 2.00 139 PPM 291027 13:09:00.8 -33:30:06 7.4 0.34 138 PPM 291067 13:10:55.0 -33:43:20 9.9 0.19 137 1437_Diomedes 13:10:38.8 -33:32:26 13.2 137 Positions are for J2000