Occultation event with (2241) Alcathous, event index number 1178
Regions able to see the event: Australia
Geocentric closest approach at 2025/07/31 20:06:03 UTC
J2000 position of star is 01:29:43.4 +26:48:14
Equinox of date position of star is 01:31:08.8 +26:56:08
Star is 167 degrees from the moon. Moon is 44% illuminated.
Stellar brightness G=15.0, apparent brightess of occulting body is G=14.3
Use an exposure time of 1.15 seconds with the standard RECON-QHY system.
SNR of 10.0 per integration for unocculted signal
Expected flux drop is 36% with SNR of 3.6 for the occulted depth (per occulted point)
Apparent velocity is 9.9 km/sec on the sky relative to the star, or, 9.3 arcsec/hr.
The recommended exposure time corresponds to 11.4 km per image.
The 1-sigma error in the time of the event is 2.1 seconds.
The 1-sigma cross-track error in the shadow position is 31.2 km.
The sky-plane scale is 3837.6 km/arcsec.
Diameter estimates:
118.6 km assuming a 5% albedo, aximum of 12.0 sec for a central chord
48.4 km assuming a 30% albedo, maximum of 4.9 sec for a central chord
Cross-track diameter of 118.6 km used for deployment plan.
Star training set for 2241_Alcathous, (2025/07/31 20:06UT) Object RA Dec mag sep mel Aldebaran 04:37:23.5 +16:33:31 0.8 44.22 141 6Bet Ari 01:56:03.5 +20:55:55 2.6 8.27 174 90Ups Psc 01:20:52.8 +27:23:52 4.8 2.33 166 PPM 090846 01:32:05.4 +26:28:49 8.5 0.50 168 PPM 090841 01:31:56.7 +26:52:51 9.2 0.19 167 2241_Alcathous 01:31:08.8 +26:56:08 14.3 167 Positions are for equinox of date
Star training set for 2241_Alcathous, (2025/07/31 20:06UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 44.22 141 6Bet Ari 01:54:38.6 +20:48:26 2.6 8.27 174 90Ups Psc 01:19:28.0 +27:15:50 4.8 2.33 166 PPM 090846 01:30:40.2 +26:20:57 8.5 0.50 168 PPM 090841 01:30:31.4 +26:44:58 9.2 0.19 167 2241_Alcathous 01:29:43.4 +26:48:14 14.3 167 Positions are for J2000