Occultation event with (1437) Diomedes, event index number 1110
Regions able to see the event: SAfrica
Geocentric closest approach at 2025/07/04 19:54:30 UTC
J2000 position of star is 11:14:12.4 -11:33:14
Equinox of date position of star is 11:15:29.5 -11:41:36
Star is 42 degrees from the moon. Moon is 69% illuminated.
Stellar brightness G=16.1, apparent brightess of occulting body is G=14.0
Use an exposure time of 1.55 seconds with the standard RECON-QHY system.
SNR of 4.3 per integration for unocculted signal
Expected flux drop is 13% with SNR of 0.5 for the occulted depth (per occulted point)
Apparent velocity is 22.0 km/sec on the sky relative to the star, or, 19.9 arcsec/hr.
Position angle of asteroid motion is 343.6 degrees
The recommended exposure time corresponds to 34.1 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 30.7 km.
The sky-plane scale is 3975.4 km/arcsec.
Diameter estimates:
139.3 km assuming a 5% albedo, aximum of 6.3 sec for a central chord
56.9 km assuming a 30% albedo, maximum of 2.6 sec for a central chord
Cross-track diameter of 139.3 km used for deployment plan.
Star training set for 1437_Diomedes, (2025/07/04 19:55UT) Object RA Dec mag sep mel Regulus 10:09:43.7 +11:50:30 1.3 28.64 65 4Gam Crv 12:17:07.3 -17:41:00 2.6 16.05 26 PPM 224159 11:16:56.7 -12:43:56 6.5 1.10 41 PPM 224154 11:16:40.7 -11:43:40 7.0 0.29 42 1437_Diomedes 11:15:29.5 -11:41:36 14.0 42 Positions are for equinox of date
Star training set for 1437_Diomedes, (2025/07/04 19:55UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 28.64 65 4Gam Crv 12:15:48.1 -17:32:30 2.6 16.05 26 PPM 224159 11:15:39.8 -12:35:34 6.5 1.10 41 PPM 224154 11:15:23.6 -11:35:18 7.0 0.29 42 1437_Diomedes 11:14:12.4 -11:33:14 14.0 42 Positions are for J2000