Occultation event with (1437) Diomedes, event index number 995
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/05/23 04:17:43 UTC
J2000 position of star is 10:59:59.9 -11:14:25
Equinox of date position of star is 11:01:16.2 -11:22:37
Star is 158 degrees from the moon. Moon is 22% illuminated.
Stellar brightness G=16.4, apparent brightess of occulting body is G=13.7
Use an exposure time of 2.00 seconds with the standard RECON-QHY system.
SNR of 3.4 per integration for unocculted signal
Expected flux drop is 8% with SNR of 0.3 for the occulted depth (per occulted point)
Apparent velocity is 4.7 km/sec on the sky relative to the star, or, 4.8 arcsec/hr.
Position angle of asteroid motion is 6.4 degrees
The recommended exposure time corresponds to 9.4 km per image.
The 1-sigma error in the time of the event is 6.8 seconds.
The 1-sigma cross-track error in the shadow position is 27.7 km.
The sky-plane scale is 3511.6 km/arcsec.
Diameter estimates:
139.3 km assuming a 5% albedo, aximum of 29.6 sec for a central chord
56.9 km assuming a 30% albedo, maximum of 12.1 sec for a central chord
Cross-track diameter of 139.3 km used for deployment plan.
Star training set for 1437_Diomedes, (2025/05/23 04:18UT) Object RA Dec mag sep mel Regulus 10:09:43.3 +11:50:32 1.3 26.51 143 4Gam Crv 12:17:06.9 -17:40:58 2.6 19.39 166 PPM 223860 11:04:31.2 -11:26:29 5.3 0.80 159 PPM 223734 10:59:43.8 -11:33:20 8.5 0.42 157 PPM 223775 11:01:23.1 -11:11:23 9.4 0.19 158 1437_Diomedes 11:01:16.2 -11:22:37 13.7 158 Positions are for equinox of date
Star training set for 1437_Diomedes, (2025/05/23 04:18UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 26.51 143 4Gam Crv 12:15:48.1 -17:32:30 2.6 19.39 166 PPM 223860 11:03:14.7 -11:18:15 5.3 0.80 159 PPM 223734 10:58:27.6 -11:25:09 8.5 0.42 157 PPM 223775 11:00:06.7 -11:03:11 9.4 0.19 158 1437_Diomedes 10:59:59.9 -11:14:25 13.7 158 Positions are for J2000