Occultation event with (4057) Demophon, event index number 3705
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/05/01 06:53:55 UTC
J2000 position of star is 11:21:47.7 +05:43:21
Equinox of date position of star is 11:23:09.3 +05:34:40
Star is 47 degrees from the moon. Moon is 100% illuminated.
Stellar brightness G=16.7, apparent brightess of occulting body is G=15.5
Use an exposure time of 2.00 seconds with the standard RECON-QHY system.
SNR of 3.8 per integration for unocculted signal
Expected flux drop is 26% with SNR of 1.0 for the occulted depth (per occulted point)
Apparent velocity is 5.7 km/sec on the sky relative to the star, or, 6.3 arcsec/hr.
Position angle of asteroid motion is 101.7 degrees
The recommended exposure time corresponds to 11.4 km per image.
The 1-sigma error in the time of the event is 4.1 seconds.
The 1-sigma cross-track error in the shadow position is 31.1 km.
The sky-plane scale is 3264.5 km/arcsec.
Diameter estimates:
53.2 km assuming a 5% albedo, maximum of 9.3 sec for a central chord
21.7 km assuming a 30% albedo, maximum of 3.8 sec for a central chord
Cross-track diameter of 45.7 km used for deployment plan.
Star training set for 4057_Demophon, (2026/05/01 06:54UT) Object RA Dec mag sep mel Regulus 10:09:46.3 +11:50:15 1.3 19.17 66 Denebola 11:50:24.1 +14:25:29 2.1 11.10 47 77Sig Leo 11:22:29.6 +05:53:05 4.0 0.35 48 PPM 157764 11:22:20.4 +04:44:09 7.8 0.87 47 PPM 157770 11:22:38.7 +05:35:48 9.4 0.13 47 PPM 157772 11:22:50.0 +05:29:14 10.7 0.12 47 4057_Demophon 11:23:09.3 +05:34:40 15.5 47 Positions are for equinox of date
Star training set for 4057_Demophon, (2026/05/01 06:54UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 19.17 66 Denebola 11:49:02.7 +14:34:16 2.1 11.10 47 77Sig Leo 11:21:08.0 +06:01:45 4.0 0.35 48 PPM 157764 11:20:59.0 +04:52:49 7.8 0.87 47 PPM 157770 11:21:17.2 +05:44:29 9.4 0.13 47 PPM 157772 11:21:28.5 +05:37:55 10.7 0.12 47 4057_Demophon 11:21:47.7 +05:43:21 15.5 47 Positions are for J2000