Occultation event with (1872) Helenos, event index number 4673
Regions able to see the event: Australia
Geocentric closest approach at 2026/11/13 17:51:59 UTC
J2000 position of star is 04:57:56.4 +07:06:31
Equinox of date position of star is 04:59:23.4 +07:08:54
Star is 148 degrees from the moon. Moon is 17% illuminated.
Stellar brightness G=14.7, apparent brightess of occulting body is G=16.0
Use an exposure time of 0.50 seconds with the standard RECON-QHY system.
SNR of 8.8 per integration for unocculted signal
Expected flux drop is 77% with SNR of 6.8 for the occulted depth (per occulted point)
Apparent velocity is 16.0 km/sec on the sky relative to the star, or, 17.4 arcsec/hr.
Position angle of asteroid motion is 68.1 degrees
The recommended exposure time corresponds to 8.0 km per image.
The 1-sigma error in the time of the event is 0.8 seconds.
The 1-sigma cross-track error in the shadow position is 33.0 km.
The sky-plane scale is 3310.9 km/arcsec.
Diameter estimates:
42.1 km assuming a 5% albedo, maximum of 2.6 sec for a central chord
17.2 km assuming a 30% albedo, maximum of 1.1 sec for a central chord
Cross-track diameter of 34.0 km used for deployment plan.
Star training set for 1872_Helenos, (2026/11/13 17:52UT) Object RA Dec mag sep mel Aldebaran 04:37:27.9 +16:33:40 0.8 10.83 148 Bellatrix 05:26:34.4 +06:22:18 1.6 6.79 152 PPM 148183 04:57:24.2 +05:26:22 6.3 1.78 146 PPM 148190 04:57:36.2 +07:56:42 6.6 0.91 148 PPM 148236 04:59:10.5 +07:21:00 9.3 0.21 148 1872_Helenos 04:59:23.4 +07:08:54 16.0 148 Positions are for equinox of date
Star training set for 1872_Helenos, (2026/11/13 17:52UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 10.83 148 Bellatrix 05:25:07.8 +06:20:58 1.6 6.79 152 PPM 148183 04:55:58.3 +05:23:56 6.3 1.78 146 PPM 148190 04:56:08.8 +07:54:16 6.6 0.91 148 PPM 148236 04:57:43.4 +07:18:37 9.3 0.21 148 1872_Helenos 04:57:56.4 +07:06:31 16.0 148 Positions are for J2000