Occultation event with (1437) Diomedes, event index number 3656
Regions able to see the event: SAmericaN,SAmericaS
Geocentric closest approach at 2026/04/19 07:15:22 UTC
J2000 position of star is 13:08:09.5 -33:22:19
Equinox of date position of star is 13:09:37.3 -33:30:42
Star is 149 degrees from the moon. Moon is 5% illuminated.
Stellar brightness G=15.7, apparent brightess of occulting body is G=13.2
Use an exposure time of 1.70 seconds with the standard RECON-QHY system.
SNR of 5.1 per integration for unocculted signal
Expected flux drop is 9% with SNR of 0.5 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 109.7 degrees
The recommended exposure time corresponds to 29.0 km per image.
The 1-sigma error in the time of the event is 1.6 seconds.
The 1-sigma cross-track error in the shadow position is 22.4 km.
The sky-plane scale is 3203.9 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, (2026/04/19 07:15UT) Object RA Dec mag sep mel Spica 13:26:34.9 -11:17:52 1.0 22.55 149 Iot Cen 13:22:05.1 -36:51:01 2.8 4.20 151 PPM 290865 13:02:30.2 -33:45:54 6.3 1.50 148 PPM 291027 13:10:28.6 -33:38:29 7.4 0.22 149 PPM 290992 13:08:57.3 -33:36:32 10.2 0.17 149 1437_Diomedes 13:09:37.3 -33:30:42 13.2 149 Positions are for equinox of date
Star training set for 1437_Diomedes, (2026/04/19 07:15UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 22.55 149 Iot Cen 13:20:35.1 -36:42:46 2.8 4.20 151 PPM 290865 13:01:03.1 -33:37:26 6.3 1.50 148 PPM 291027 13:09:00.8 -33:30:06 7.4 0.22 149 PPM 290992 13:07:29.6 -33:28:08 10.2 0.17 149 1437_Diomedes 13:08:09.5 -33:22:19 13.2 149 Positions are for J2000