Occultation event with (1647) Menelaus, event index number 1574
Regions able to see the event: Australia
Geocentric closest approach at 2025/11/23 20:30:48 UTC
J2000 position of star is 10:49:23.3 +01:30:34
Equinox of date position of star is 10:50:43.2 +01:22:19
Star is 117 degrees from the moon. Moon is 11% illuminated.
Stellar brightness G=13.0, apparent brightess of occulting body is G=16.1
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 11.2 per integration for unocculted signal
Expected flux drop is 95% with SNR of 10.6 for the occulted depth (per occulted point)
Apparent velocity is 19.1 km/sec on the sky relative to the star, or, 18.2 arcsec/hr.
Position angle of asteroid motion is 120.1 degrees
The recommended exposure time corresponds to 2.3 km per image.
The 1-sigma error in the time of the event is 1.3 seconds.
The 1-sigma cross-track error in the shadow position is 20.4 km.
The sky-plane scale is 3770.6 km/arcsec.
Diameter estimates:
48.5 km assuming a 5% albedo, aximum of 2.5 sec for a central chord
19.8 km assuming a 30% albedo, maximum of 1.0 sec for a central chord
Cross-track diameter of 42.7 km used for deployment plan.
Star training set for 1647_Menelaus, (2025/11/23 20:31UT) Object RA Dec mag sep mel Regulus 10:09:44.9 +11:50:23 1.3 14.59 131 55 Leo 10:57:02.3 +00:35:54 6.2 1.76 115 PPM 157264 10:52:29.0 +00:38:53 8.2 0.85 116 PPM 157222 10:50:08.8 +01:15:58 8.9 0.18 117 1647_Menelaus 10:50:43.2 +01:22:19 16.1 117 Positions are for equinox of date
Star training set for 1647_Menelaus, (2025/11/23 20:31UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 14.59 131 55 Leo 10:55:42.5 +00:44:13 6.2 1.76 115 PPM 157264 10:51:09.2 +00:47:10 8.2 0.85 116 PPM 157222 10:48:48.9 +01:24:12 8.9 0.18 117 1647_Menelaus 10:49:23.3 +01:30:34 16.1 117 Positions are for J2000