Occultation event with (3540) Protesilaos, event index number 885
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/04/05 06:45:01 UTC
J2000 position of star is 10:00:09.2 +36:32:40
Equinox of date position of star is 10:01:39.3 +36:25:20
Star is 35 degrees from the moon. Moon is 52% illuminated.
Stellar brightness G=15.2, apparent brightess of occulting body is G=14.3
Use an exposure time of 1.60 seconds with the standard RECON-QHY system.
Expected flux drop is 70% with SNR of 10.0 per integration
Apparent velocity is 11.9 km/sec on the sky relative to the star, or, 14.5 arcsec/hr.
The recommended exposure time corresponds to 19.1 km per image.
The 1-sigma error in the time of the event is 2.7 seconds.
The 1-sigma cross-track error in the shadow position is 47.5 km.
The sky-plane scale is 2951.2 km/arcsec.
Diameter estimates:
78.7 km assuming a 5% albedo, aximum of 6.6 sec for a central chord
32.1 km assuming a 30% albedo, maximum of 2.7 sec for a central chord
Cross-track diameter of 78.7 km used for deployment plan.
Star training set for 3540_Protesilaos, (2025/04/05 06:45UT) Object RA Dec mag sep mel Regulus 10:09:42.9 +11:50:34 1.3 24.65 42 Merak 11:03:21.0 +56:14:47 2.4 22.39 49 21 LMi 10:08:54.7 +35:07:13 4.6 1.97 36 PPM 074928 10:03:02.8 +36:23:17 8.5 0.28 35 PPM 074914 10:01:51.2 +36:15:28 10.3 0.17 35 3540_Protesila 10:01:39.3 +36:25:20 14.3 35 Positions are for equinox of date
Star training set for 3540_Protesilaos, (2025/04/05 06:45UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 24.65 42 Merak 11:01:50.7 +56:22:58 2.4 22.39 49 21 LMi 10:07:25.9 +35:14:41 4.6 1.97 36 PPM 074928 10:01:32.8 +36:30:38 8.5 0.28 35 PPM 074914 10:00:21.2 +36:22:47 10.3 0.17 35 3540_Protesila 10:00:09.2 +36:32:40 14.3 35 Positions are for J2000