Occultation event with (2357) Phereclos, event index number 3942
Regions able to see the event: SMexico
Geocentric closest approach at 2026/08/05 09:13:26 UTC
J2000 position of star is 05:00:43.2 +20:27:23
Equinox of date position of star is 05:02:17.9 +20:29:38
Star is 43 degrees from the moon. Moon is 58% illuminated.
Stellar brightness G=15.1, apparent brightess of occulting body is G=15.0
Use an exposure time of 0.80 seconds with the standard RECON-QHY system.
SNR of 8.2 per integration for unocculted signal
Expected flux drop is 48% with SNR of 3.9 for the occulted depth (per occulted point)
Apparent velocity is 28.3 km/sec on the sky relative to the star, or, 23.6 arcsec/hr.
Position angle of asteroid motion is 86.4 degrees
The recommended exposure time corresponds to 22.7 km per image.
The 1-sigma error in the time of the event is 0.2 seconds.
The 1-sigma cross-track error in the shadow position is 33.3 km.
The sky-plane scale is 4320.5 km/arcsec.
Diameter estimates:
95.9 km assuming a 5% albedo, maximum of 3.4 sec for a central chord
39.2 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 94.6 km used for deployment plan.
Star training set for 2357_Phereclos, (2026/08/05 09:13UT) Object RA Dec mag sep mel Aldebaran 04:37:27.0 +16:33:38 0.8 7.08 37 Alnath 05:27:58.5 +28:37:38 1.6 10.01 49 102Iot Tau 05:04:41.3 +21:37:32 4.6 1.26 43 PPM 093957 05:01:48.8 +20:57:55 8.4 0.48 43 PPM 093940 05:01:00.1 +20:13:56 9.3 0.40 43 PPM 093968 05:02:23.4 +20:18:47 11.5 0.18 43 2357_Phereclos 05:02:17.9 +20:29:38 15.0 43 Positions are for equinox of date
Star training set for 2357_Phereclos, (2026/08/05 09:13UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 7.08 37 Alnath 05:26:17.6 +28:36:22 1.6 10.01 49 102Iot Tau 05:03:05.9 +21:35:23 4.6 1.26 43 PPM 093957 05:00:13.9 +20:55:40 8.4 0.48 43 PPM 093940 04:59:25.7 +20:11:39 9.3 0.40 43 PPM 093968 05:00:48.9 +20:16:33 11.5 0.18 43 2357_Phereclos 05:00:43.2 +20:27:23 15.0 43 Positions are for J2000