Occultation event with (4057) Demophon, event index number 3697
Regions able to see the event: Australia
Geocentric closest approach at 2026/04/29 13:17:41 UTC
J2000 position of star is 11:22:05.9 +05:42:22
Equinox of date position of star is 11:23:27.4 +05:33:41
Star is 26 degrees from the moon. Moon is 95% illuminated.
Stellar brightness G=10.5, apparent brightess of occulting body is G=15.5
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 46.5 per integration for unocculted signal
Expected flux drop is 99% with SNR of 46.0 for the occulted depth (per occulted point)
Apparent velocity is 6.4 km/sec on the sky relative to the star, or, 7.1 arcsec/hr.
Position angle of asteroid motion is 103.0 degrees
The recommended exposure time corresponds to 0.8 km per image.
The 1-sigma error in the time of the event is 3.9 seconds.
The 1-sigma cross-track error in the shadow position is 31.1 km.
The sky-plane scale is 3248.5 km/arcsec.
Diameter estimates:
53.2 km assuming a 5% albedo, maximum of 8.3 sec for a central chord
21.7 km assuming a 30% albedo, maximum of 3.4 sec for a central chord
Cross-track diameter of 45.7 km used for deployment plan.
Star training set for 4057_Demophon, (2026/04/29 13:18UT) Object RA Dec mag sep mel Regulus 10:09:46.3 +11:50:15 1.3 19.25 45 Denebola 11:50:24.1 +14:25:29 2.1 11.07 28 77Sig Leo 11:22:29.6 +05:53:05 4.0 0.40 26 PPM 157764 11:22:20.4 +04:44:09 7.8 0.87 26 PPM 157770 11:22:38.7 +05:35:48 9.4 0.21 26 PPM 157772 11:22:50.0 +05:29:14 10.7 0.17 26 4057_Demophon 11:23:27.4 +05:33:41 15.5 26 Positions are for equinox of date
Star training set for 4057_Demophon, (2026/04/29 13:18UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 19.25 45 Denebola 11:49:02.7 +14:34:16 2.1 11.07 28 77Sig Leo 11:21:08.0 +06:01:45 4.0 0.40 26 PPM 157764 11:20:59.0 +04:52:49 7.8 0.87 26 PPM 157770 11:21:17.2 +05:44:29 9.4 0.21 26 PPM 157772 11:21:28.5 +05:37:55 10.7 0.17 26 4057_Demophon 11:22:05.9 +05:42:22 15.5 26 Positions are for J2000