Occultation event with (4057) Demophon, event index number 3526
Regions able to see the event: SAmericaS
Geocentric closest approach at 2026/03/28 07:03:48 UTC
J2000 position of star is 11:33:13.2 +04:47:01
Equinox of date position of star is 11:34:34.2 +04:38:18
Star is 42 degrees from the moon. Moon is 77% illuminated.
Stellar brightness G=13.7, apparent brightess of occulting body is G=15.0
Use an exposure time of 0.20 seconds with the standard RECON-QHY system.
SNR of 9.0 per integration for unocculted signal
Expected flux drop is 77% with SNR of 6.9 for the occulted depth (per occulted point)
Apparent velocity is 15.8 km/sec on the sky relative to the star, or, 18.7 arcsec/hr.
Position angle of asteroid motion is 110.4 degrees
The recommended exposure time corresponds to 3.2 km per image.
The 1-sigma error in the time of the event is 1.8 seconds.
The 1-sigma cross-track error in the shadow position is 27.3 km.
The sky-plane scale is 3037.4 km/arcsec.
Diameter estimates:
53.2 km assuming a 5% albedo, maximum of 3.4 sec for a central chord
21.7 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 45.7 km used for deployment plan.
Star training set for 4057_Demophon, (2026/03/28 07:04UT) Object RA Dec mag sep mel Regulus 10:09:46.0 +11:50:17 1.3 22.17 20 Denebola 11:50:23.8 +14:25:31 2.1 10.53 43 89 Leo 11:35:42.5 +02:54:51 6.2 1.75 43 PPM 157971 11:34:40.6 +03:13:01 8.1 1.42 43 PPM 157959 11:34:15.3 +04:43:35 9.8 0.12 42 4057_Demophon 11:34:34.2 +04:38:18 15.0 43 Positions are for equinox of date
Star training set for 4057_Demophon, (2026/03/28 07:04UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 22.17 20 Denebola 11:49:02.7 +14:34:16 2.1 10.53 43 89 Leo 11:34:21.6 +03:03:34 6.2 1.75 43 PPM 157971 11:33:19.7 +03:21:44 8.1 1.42 43 PPM 157959 11:32:54.3 +04:52:17 9.8 0.12 42 4057_Demophon 11:33:13.2 +04:47:01 15.0 42 Positions are for J2000