Occultation event with (1647) Menelaus, event index number 3499
Regions able to see the event: Australia
Geocentric closest approach at 2026/03/25 11:33:58 UTC
J2000 position of star is 10:27:20.2 +02:27:22
Equinox of date position of star is 10:28:41.4 +02:19:18
Star is 68 degrees from the moon. Moon is 46% illuminated.
Stellar brightness G=15.3, apparent brightess of occulting body is G=15.4
Use an exposure time of 0.75 seconds with the standard RECON-QHY system.
SNR of 6.6 per integration for unocculted signal
Expected flux drop is 51% with SNR of 3.4 for the occulted depth (per occulted point)
Apparent velocity is 13.7 km/sec on the sky relative to the star, or, 16.2 arcsec/hr.
Position angle of asteroid motion is 118.6 degrees
The recommended exposure time corresponds to 10.3 km per image.
The 1-sigma error in the time of the event is 1.9 seconds.
The 1-sigma cross-track error in the shadow position is 21.6 km.
The sky-plane scale is 3031.2 km/arcsec.
Diameter estimates:
48.5 km assuming a 5% albedo, maximum of 3.5 sec for a central chord
19.8 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 42.7 km used for deployment plan.
Star training set for 1647_Menelaus, (2026/03/25 11:34UT) Object RA Dec mag sep mel Regulus 10:09:46.0 +11:50:17 1.3 10.61 59 30Bet Sex 10:31:37.9 -00:46:21 4.8 3.18 70 PPM 156876 10:30:20.0 +02:30:41 7.5 0.45 68 PPM 156832 10:27:41.4 +02:24:52 9.5 0.27 68 1647_Menelaus 10:28:41.4 +02:19:18 15.4 68 Positions are for equinox of date
Star training set for 1647_Menelaus, (2026/03/25 11:34UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 10.61 59 30Bet Sex 10:30:17.4 -00:38:14 4.8 3.18 70 PPM 156876 10:28:58.7 +02:38:46 7.5 0.45 68 PPM 156832 10:26:20.2 +02:32:55 9.5 0.27 68 1647_Menelaus 10:27:20.2 +02:27:22 15.4 68 Positions are for J2000