Occultation event with (4543) Phoinix, event index number 1155
Regions able to see the event: SAmericaS
Geocentric closest approach at 2025/07/22 00:36:16 UTC
J2000 position of star is 11:31:52.1 -06:30:14
Equinox of date position of star is 11:33:10.2 -06:38:42
Star is 94 degrees from the moon. Moon is 10% illuminated.
Stellar brightness G=13.0, apparent brightess of occulting body is G=15.8
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 11.2 per integration for unocculted signal
Expected flux drop is 93% with SNR of 10.4 for the occulted depth (per occulted point)
Apparent velocity is 28.1 km/sec on the sky relative to the star, or, 23.4 arcsec/hr.
Position angle of asteroid motion is 335.4 degrees
The recommended exposure time corresponds to 3.4 km per image.
The 1-sigma error in the time of the event is 1.5 seconds.
The 1-sigma cross-track error in the shadow position is 35.5 km.
The sky-plane scale is 4318.1 km/arcsec.
Diameter estimates:
66.7 km assuming a 5% albedo, aximum of 2.4 sec for a central chord
27.2 km assuming a 30% albedo, maximum of 1.0 sec for a central chord
Cross-track diameter of 66.7 km used for deployment plan.
Star training set for 4543_Phoinix, (2025/07/22 00:36UT) Object RA Dec mag sep mel Regulus 10:09:43.8 +11:50:29 1.3 27.79 67 4Gam Crv 12:17:07.4 -17:41:01 2.6 15.39 108 PPM 194572 11:34:05.6 -07:58:08 5.8 1.34 95 PPM 194554 11:33:14.7 -06:36:45 6.9 0.04 94 4543_Phoinix 11:33:10.2 -06:38:42 15.8 94 Positions are for equinox of date
Star training set for 4543_Phoinix, (2025/07/22 00:36UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 27.79 67 4Gam Crv 12:15:48.1 -17:32:30 2.6 15.39 108 PPM 194572 11:32:47.5 -07:49:39 5.8 1.34 95 PPM 194554 11:31:56.6 -06:28:16 6.9 0.04 94 4543_Phoinix 11:31:52.1 -06:30:14 15.8 94 Positions are for J2000