Occultation event with (2241) Alcathous, event index number 1292
Regions able to see the event: US
Geocentric closest approach at 2025/09/17 12:56:32 UTC
J2000 position of star is 01:22:42.9 +27:55:20
Equinox of date position of star is 01:24:08.5 +28:03:22
Star is 93 degrees from the moon. Moon is 18% illuminated.
Stellar brightness G=13.1, apparent brightess of occulting body is G=13.9
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 9.6 per integration for unocculted signal
Expected flux drop is 68% with SNR of 6.5 for the occulted depth (per occulted point)
Apparent velocity is 12.8 km/sec on the sky relative to the star, or, 13.6 arcsec/hr.
Position angle of asteroid motion is 81.4 degrees
The recommended exposure time corresponds to 1.5 km per image.
The 1-sigma error in the time of the event is 1.1 seconds.
The 1-sigma cross-track error in the shadow position is 32.3 km.
The sky-plane scale is 3406.0 km/arcsec.
Diameter estimates:
118.6 km assuming a 5% albedo, aximum of 9.2 sec for a central chord
48.4 km assuming a 30% albedo, maximum of 3.8 sec for a central chord
Cross-track diameter of 113.7 km used for deployment plan.
Star training set for 2241_Alcathous, (2025/09/17 12:57UT) Object RA Dec mag sep mel Aldebaran 04:37:23.9 +16:33:32 0.8 45.85 55 6Bet Ari 01:56:04.0 +20:55:57 2.6 10.17 90 90Ups Psc 01:20:53.2 +27:23:54 4.8 0.98 94 PPM 090789 01:28:09.5 +27:22:44 7.3 1.12 93 PPM 090736 01:24:46.1 +27:46:54 8.8 0.31 93 PPM 090724 01:23:56.9 +28:09:59 11.0 0.12 93 2241_Alcathous 01:24:08.5 +28:03:22 13.9 93 Positions are for equinox of date
Star training set for 2241_Alcathous, (2025/09/17 12:57UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 45.85 55 6Bet Ari 01:54:38.6 +20:48:26 2.6 10.17 90 90Ups Psc 01:19:28.0 +27:15:50 4.8 0.98 94 PPM 090789 01:26:43.8 +27:14:46 7.3 1.12 93 PPM 090736 01:23:20.6 +27:38:53 8.8 0.31 93 PPM 090724 01:22:31.3 +28:01:58 11.0 0.12 93 2241_Alcathous 01:22:42.9 +27:55:20 13.9 93 Positions are for J2000