Occultation event with (4836) Medon, event index number 1708
Regions able to see the event: Europe
Geocentric closest approach at 2025/12/22 02:39:53 UTC
J2000 position of star is 13:42:14.8 +08:25:26
Equinox of date position of star is 13:43:32.4 +08:17:37
Star is 94 degrees from the moon. Moon is 4% illuminated.
Stellar brightness G=14.9, apparent brightess of occulting body is G=15.1
Use an exposure time of 0.65 seconds with the standard RECON-QHY system.
SNR of 8.4 per integration for unocculted signal
Expected flux drop is 56% with SNR of 4.7 for the occulted depth (per occulted point)
Apparent velocity is 24.2 km/sec on the sky relative to the star, or, 23.0 arcsec/hr.
Position angle of asteroid motion is 96.4 degrees
The recommended exposure time corresponds to 15.8 km per image.
The 1-sigma error in the time of the event is 0.9 seconds.
The 1-sigma cross-track error in the shadow position is 27.9 km.
The sky-plane scale is 3789.5 km/arcsec.
Diameter estimates:
74.1 km assuming a 5% albedo, aximum of 3.1 sec for a central chord
30.3 km assuming a 30% albedo, maximum of 1.2 sec for a central chord
Cross-track diameter of 63.3 km used for deployment plan.
Star training set for 4836_Medon, (2025/12/22 02:40UT) Object RA Dec mag sep mel Arcturus 14:16:50.9 +19:02:55 0.0 13.45 91 Vindemiatrix 13:03:28.2 +10:49:12 2.8 10.20 104 PPM 129981 13:40:51.5 +10:36:55 5.8 2.41 95 PPM 159981 13:43:29.8 +08:15:27 6.6 0.04 94 4836_Medon 13:43:32.4 +08:17:37 15.1 93 Positions are for equinox of date
Star training set for 4836_Medon, (2025/12/22 02:40UT) Object RA Dec mag sep mel Arcturus 14:15:37.7 +19:10:06 0.0 13.45 91 Vindemiatrix 13:02:10.1 +10:57:33 2.8 10.20 104 PPM 129981 13:39:34.4 +10:44:46 5.8 2.41 95 PPM 159981 13:42:12.1 +08:23:16 6.6 0.04 94 4836_Medon 13:42:14.8 +08:25:26 15.1 94 Positions are for J2000