Occultation event with (1872) Helenos, event index number 4596
Regions able to see the event: Australia
Geocentric closest approach at 2026/11/07 14:42:21 UTC
J2000 position of star is 05:00:27.4 +07:23:09
Equinox of date position of star is 05:01:54.5 +07:25:25
Star is 128 degrees from the moon. Moon is 3% illuminated.
Stellar brightness G=16.2, apparent brightess of occulting body is G=16.1
Use an exposure time of 0.70 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 46% with SNR of 1.4 for the occulted depth (per occulted point)
Apparent velocity is 14.8 km/sec on the sky relative to the star, or, 15.9 arcsec/hr.
Position angle of asteroid motion is 63.8 degrees
The recommended exposure time corresponds to 10.3 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 32.2 km.
The sky-plane scale is 3339.1 km/arcsec.
Diameter estimates:
42.1 km assuming a 5% albedo, maximum of 2.8 sec for a central chord
17.2 km assuming a 30% albedo, maximum of 1.2 sec for a central chord
Cross-track diameter of 34.0 km used for deployment plan.
Star training set for 1872_Helenos, (2026/11/07 14:42UT) Object RA Dec mag sep mel Aldebaran 04:37:27.9 +16:33:40 0.8 10.91 135 Bellatrix 05:26:34.4 +06:22:18 1.6 6.21 122 14 Ori 05:09:20.7 +08:31:53 5.7 2.15 126 PPM 148328 05:03:10.9 +06:47:19 8.3 0.71 127 PPM 148288 05:01:46.0 +07:35:22 9.6 0.17 128 1872_Helenos 05:01:54.5 +07:25:25 16.1 127 Positions are for equinox of date
Star training set for 1872_Helenos, (2026/11/07 14:42UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 10.91 135 Bellatrix 05:25:07.8 +06:20:58 1.6 6.21 122 14 Ori 05:07:52.9 +08:29:53 5.7 2.15 126 PPM 148328 05:01:44.2 +06:45:06 8.3 0.71 127 PPM 148288 05:00:18.8 +07:33:05 9.6 0.17 128 1872_Helenos 05:00:27.4 +07:23:09 16.1 128 Positions are for J2000