Occultation event with (4902) Thessandrus, event index number 3156
Regions able to see the event: Australia
Geocentric closest approach at 2026/01/18 18:56:13 UTC
J2000 position of star is 11:49:44.3 +00:39:56
Equinox of date position of star is 11:51:04.4 +00:31:14
Star is 121 degrees from the moon. Moon is 0% illuminated.
Stellar brightness G=16.3, apparent brightess of occulting body is G=15.2
Use an exposure time of 2.00 seconds with the standard RECON-QHY system.
SNR of 5.0 per integration for unocculted signal
Expected flux drop is 25% with SNR of 1.3 for the occulted depth (per occulted point)
Apparent velocity is 3.4 km/sec on the sky relative to the star, or, 3.6 arcsec/hr.
Position angle of asteroid motion is 147.9 degrees
The recommended exposure time corresponds to 6.7 km per image.
The 1-sigma error in the time of the event is 10.8 seconds.
The 1-sigma cross-track error in the shadow position is 11.7 km.
The sky-plane scale is 3332.6 km/arcsec.
Diameter estimates:
64.9 km assuming a 5% albedo, maximum of 19.3 sec for a central chord
26.5 km assuming a 30% albedo, maximum of 7.9 sec for a central chord
Cross-track diameter of 51.3 km used for deployment plan.
Star training set for 4902_Thessandrus, (2026/01/18 18:56UT) Object RA Dec mag sep mel Spica 13:26:34.2 -11:17:47 1.0 26.50 94 Denebola 11:50:23.2 +14:25:35 2.1 13.91 126 5Bet Vir 11:52:03.1 +01:37:04 3.6 1.12 121 PPM 158301 11:55:10.3 +00:24:26 6.6 1.03 120 PPM 158256 11:51:47.0 +00:51:43 10.1 0.38 121 4902_Thessandr 11:51:04.4 +00:31:14 15.2 120 Positions are for equinox of date
Star training set for 4902_Thessandrus, (2026/01/18 18:56UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 26.50 94 Denebola 11:49:02.7 +14:34:16 2.1 13.91 126 5Bet Vir 11:50:43.0 +01:45:46 3.6 1.12 121 PPM 158301 11:53:50.2 +00:33:08 6.6 1.03 120 PPM 158256 11:50:26.9 +01:00:24 10.1 0.38 121 4902_Thessandr 11:49:44.3 +00:39:56 15.2 121 Positions are for J2000