Occultation event with (1437) Diomedes, event index number 3861
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/07/19 01:55:29 UTC
J2000 position of star is 12:58:46.2 -28:35:42
Equinox of date position of star is 13:00:12.8 -28:44:17
Star is 32 degrees from the moon. Moon is 27% illuminated.
Stellar brightness G=14.7, apparent brightess of occulting body is G=13.9
Use an exposure time of 0.85 seconds with the standard RECON-QHY system.
SNR of 10.0 per integration for unocculted signal
Expected flux drop is 34% with SNR of 3.4 for the occulted depth (per occulted point)
Apparent velocity is 15.7 km/sec on the sky relative to the star, or, 14.7 arcsec/hr.
Position angle of asteroid motion is 80.8 degrees
The recommended exposure time corresponds to 13.4 km per image.
The 1-sigma error in the time of the event is 0.8 seconds.
The 1-sigma cross-track error in the shadow position is 31.5 km.
The sky-plane scale is 3842.5 km/arcsec.
Diameter estimates:
140.6 km assuming a 5% albedo, maximum of 8.9 sec for a central chord
57.4 km assuming a 30% albedo, maximum of 3.6 sec for a central chord
Cross-track diameter of 117.8 km used for deployment plan.
Star training set for 1437_Diomedes, (2026/07/19 01:55UT) Object RA Dec mag sep mel Spica 13:26:35.7 -11:17:57 1.0 18.50 25 9Bet Crv 12:35:47.2 -23:32:35 2.6 7.55 24 PPM 260903 12:53:23.5 -26:52:54 6.4 2.39 29 PPM 261132 13:03:49.4 -28:25:42 6.6 0.85 32 PPM 261073 13:00:39.9 -28:54:22 9.6 0.20 32 1437_Diomedes 13:00:12.8 -28:44:17 13.9 32 Positions are for equinox of date
Star training set for 1437_Diomedes, (2026/07/19 01:55UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 18.50 25 9Bet Crv 12:34:23.2 -23:23:50 2.6 7.55 24 PPM 260903 12:51:57.7 -26:44:16 6.4 2.39 29 PPM 261132 13:02:22.6 -28:17:10 6.6 0.85 32 PPM 261073 12:59:13.2 -28:45:48 9.6 0.20 32 1437_Diomedes 12:58:46.2 -28:35:42 13.9 32 Positions are for J2000