Occultation event with (2241) Alcathous, event index number 1333
Regions able to see the event: Australia
Geocentric closest approach at 2025/10/03 14:20:37 UTC
J2000 position of star is 01:15:20.2 +27:28:55
Equinox of date position of star is 01:16:45.2 +27:37:03
Star is 67 degrees from the moon. Moon is 84% illuminated.
Stellar brightness G=16.2, apparent brightess of occulting body is G=13.7
Use an exposure time of 1.70 seconds with the standard RECON-QHY system.
SNR of 3.6 per integration for unocculted signal
Expected flux drop is 9% with SNR of 0.3 for the occulted depth (per occulted point)
Apparent velocity is 16.4 km/sec on the sky relative to the star, or, 17.7 arcsec/hr.
Position angle of asteroid motion is 69.7 degrees
The recommended exposure time corresponds to 27.9 km per image.
The 1-sigma error in the time of the event is 1.2 seconds.
The 1-sigma cross-track error in the shadow position is 28.1 km.
The sky-plane scale is 3329.9 km/arcsec.
Diameter estimates:
118.6 km assuming a 5% albedo, aximum of 7.2 sec for a central chord
48.4 km assuming a 30% albedo, maximum of 3.0 sec for a central chord
Cross-track diameter of 113.7 km used for deployment plan.
Star training set for 2241_Alcathous, (2025/10/03 14:21UT) Object RA Dec mag sep mel Aldebaran 04:37:24.1 +16:33:32 0.8 47.45 106 6Bet Ari 01:56:04.1 +20:55:58 2.6 11.17 71 90Ups Psc 01:20:53.3 +27:23:55 4.8 0.94 67 PPM 090640 01:18:28.8 +28:07:11 8.0 0.63 67 PPM 090612 01:16:46.2 +27:19:13 9.8 0.30 67 PPM 090600 01:15:54.9 +27:32:16 10.8 0.20 67 2241_Alcathous 01:16:45.2 +27:37:03 13.7 67 Positions are for equinox of date
Star training set for 2241_Alcathous, (2025/10/03 14:21UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 47.45 106 6Bet Ari 01:54:38.6 +20:48:26 2.6 11.17 71 90Ups Psc 01:19:28.0 +27:15:50 4.8 0.94 67 PPM 090640 01:17:03.5 +27:59:04 8.0 0.63 67 PPM 090612 01:15:21.2 +27:11:05 9.8 0.30 67 PPM 090600 01:14:29.9 +27:24:08 10.8 0.20 67 2241_Alcathous 01:15:20.2 +27:28:55 13.7 67 Positions are for J2000