Occultation event with (1437) Diomedes, event index number 3746
Regions able to see the event: SAmericaS
Geocentric closest approach at 2026/05/15 05:07:11 UTC
J2000 position of star is 12:55:29.9 -31:51:38
Equinox of date position of star is 12:56:56.3 -32:00:11
Star is 160 degrees from the moon. Moon is 4% illuminated.
Stellar brightness G=15.7, apparent brightess of occulting body is G=13.4
Use an exposure time of 2.00 seconds with the standard RECON-QHY system.
SNR of 5.8 per integration for unocculted signal
Expected flux drop is 11% with SNR of 0.6 for the occulted depth (per occulted point)
Apparent velocity is 14.1 km/sec on the sky relative to the star, or, 15.5 arcsec/hr.
Position angle of asteroid motion is 131.2 degrees
The recommended exposure time corresponds to 28.2 km per image.
The 1-sigma error in the time of the event is 2.4 seconds.
The 1-sigma cross-track error in the shadow position is 9.7 km.
The sky-plane scale is 3271.1 km/arcsec.
Diameter estimates:
140.6 km assuming a 5% albedo, maximum of 10.0 sec for a central chord
57.4 km assuming a 30% albedo, maximum of 4.1 sec for a central chord
Cross-track diameter of 117.8 km used for deployment plan.
Star training set for 1437_Diomedes, (2026/05/15 05:07UT) Object RA Dec mag sep mel Spica 13:26:35.2 -11:17:53 1.0 21.80 172 Iot Cen 13:22:05.3 -36:51:02 2.8 7.10 158 PPM 290854 13:01:59.7 -33:38:51 6.0 1.96 159 PPM 290701 12:54:25.7 -32:00:00 8.5 0.53 159 PPM 290749 12:57:15.4 -32:13:20 9.9 0.23 159 1437_Diomedes 12:56:56.3 -32:00:11 13.4 160 Positions are for equinox of date
Star training set for 1437_Diomedes, (2026/05/15 05:07UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 21.80 172 Iot Cen 13:20:35.1 -36:42:46 2.8 7.10 158 PPM 290854 13:00:32.5 -33:30:21 6.0 1.96 159 PPM 290701 12:52:59.5 -31:51:26 8.5 0.53 159 PPM 290749 12:55:48.9 -32:04:47 9.9 0.23 159 1437_Diomedes 12:55:29.9 -31:51:38 13.4 160 Positions are for J2000