Occultation event with (4791) Iphidamas, event index number 4187
Regions able to see the event: Japan
Geocentric closest approach at 2026/09/05 19:58:07 UTC
J2000 position of star is 04:40:05.3 +32:10:41
Equinox of date position of star is 04:41:48.5 +32:13:42
Star is 21 degrees from the moon. Moon is 33% illuminated.
Stellar brightness G=15.9, apparent brightess of occulting body is G=15.4
Use an exposure time of 1.05 seconds with the standard RECON-QHY system.
SNR of 5.1 per integration for unocculted signal
Expected flux drop is 40% with SNR of 2.0 for the occulted depth (per occulted point)
Apparent velocity is 11.7 km/sec on the sky relative to the star, or, 12.1 arcsec/hr.
Position angle of asteroid motion is 86.9 degrees
The recommended exposure time corresponds to 12.3 km per image.
The 1-sigma error in the time of the event is 0.6 seconds.
The 1-sigma cross-track error in the shadow position is 27.8 km.
The sky-plane scale is 3488.1 km/arcsec.
Diameter estimates:
59.2 km assuming a 5% albedo, maximum of 5.0 sec for a central chord
24.1 km assuming a 30% albedo, maximum of 2.1 sec for a central chord
Cross-track diameter of 49.5 km used for deployment plan.
Star training set for 4791_Iphidamas, (2026/09/05 19:58UT) Object RA Dec mag sep mel Aldebaran 04:37:27.3 +16:33:39 0.8 15.70 25 3Iot Aur 04:58:44.1 +33:12:21 2.7 3.69 18 PPM 069605 04:45:32.1 +32:54:47 6.5 1.04 20 PPM 069566 04:40:57.3 +31:47:31 8.3 0.47 21 PPM 069571 04:41:36.9 +32:04:26 9.9 0.16 21 4791_Iphidamas 04:41:48.5 +32:13:42 15.4 21 Positions are for equinox of date
Star training set for 4791_Iphidamas, (2026/09/05 19:58UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 15.70 25 3Iot Aur 04:56:59.6 +33:09:57 2.7 3.69 18 PPM 069605 04:43:48.2 +32:51:55 6.5 1.04 20 PPM 069566 04:39:14.5 +31:44:29 8.3 0.47 21 PPM 069571 04:39:53.8 +32:01:25 9.9 0.16 21 4791_Iphidamas 04:40:05.3 +32:10:41 15.4 21 Positions are for J2000