Occultation event with (9431) Pytho, event index number 3674
Regions able to see the event: Europe
Geocentric closest approach at 2026/04/22 20:01:53 UTC
J2000 position of star is 11:23:33.0 -06:11:31
Equinox of date position of star is 11:24:53.3 -06:20:12
Star is 69 degrees from the moon. Moon is 36% illuminated.
Stellar brightness G=14.3, apparent brightess of occulting body is G=16.0
Use an exposure time of 0.40 seconds with the standard RECON-QHY system.
SNR of 9.7 per integration for unocculted signal
Expected flux drop is 82% with SNR of 8.0 for the occulted depth (per occulted point)
Apparent velocity is 13.8 km/sec on the sky relative to the star, or, 14.7 arcsec/hr.
Position angle of asteroid motion is 143.2 degrees
The recommended exposure time corresponds to 5.5 km per image.
The 1-sigma error in the time of the event is 2.2 seconds.
The 1-sigma cross-track error in the shadow position is 19.7 km.
The sky-plane scale is 3392.4 km/arcsec.
Diameter estimates:
44.9 km assuming a 5% albedo, maximum of 3.2 sec for a central chord
18.3 km assuming a 30% albedo, maximum of 1.3 sec for a central chord
Cross-track diameter of 38.4 km used for deployment plan.
Star training set for 9431_Pytho, (2026/04/22 20:02UT) Object RA Dec mag sep mel Regulus 10:09:46.2 +11:50:15 1.3 26.06 44 4Gam Crv 12:17:09.8 -17:41:16 2.6 17.08 86 PPM 194312 11:18:18.2 -07:16:43 6.1 1.89 68 PPM 194426 11:25:42.0 -06:03:20 7.3 0.35 69 PPM 194419 11:25:10.6 -06:24:35 9.6 0.10 69 9431_Pytho 11:24:53.3 -06:20:12 16.0 69 Positions are for equinox of date
Star training set for 9431_Pytho, (2026/04/22 20:02UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 26.06 44 4Gam Crv 12:15:48.1 -17:32:30 2.6 17.08 86 PPM 194312 11:16:58.2 -07:08:05 6.1 1.89 68 PPM 194426 11:24:21.6 -05:54:39 7.3 0.35 69 PPM 194419 11:23:50.3 -06:15:54 9.6 0.10 69 9431_Pytho 11:23:33.0 -06:11:31 16.0 69 Positions are for J2000