Occultation event with (4007) Euryalos, event index number 3662
Regions able to see the event: SAmericaS
Geocentric closest approach at 2026/04/20 04:23:22 UTC
J2000 position of star is 12:24:29.0 -03:49:35
Equinox of date position of star is 12:25:50.1 -03:58:19
Star is 120 degrees from the moon. Moon is 10% illuminated.
Stellar brightness G=16.5, apparent brightess of occulting body is G=15.3
Use an exposure time of 1.05 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 26% with SNR of 0.8 for the occulted depth (per occulted point)
Apparent velocity is 15.1 km/sec on the sky relative to the star, or, 17.3 arcsec/hr.
Position angle of asteroid motion is 104.7 degrees
The recommended exposure time corresponds to 15.8 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 23.9 km.
The sky-plane scale is 3129.9 km/arcsec.
Diameter estimates:
51.8 km assuming a 5% albedo, maximum of 3.4 sec for a central chord
21.1 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 45.5 km used for deployment plan.
Star training set for 4007_Euryalos, (2026/04/20 04:23UT) Object RA Dec mag sep mel Spica 13:26:34.9 -11:17:52 1.0 16.73 136 4Gam Crv 12:17:09.8 -17:41:16 2.6 13.88 123 PPM 195518 12:29:12.6 -04:45:38 6.2 1.15 121 PPM 195499 12:28:22.2 -03:40:52 8.4 0.70 120 PPM 195457 12:26:25.5 -04:11:17 9.7 0.26 120 4007_Euryalos 12:25:50.1 -03:58:19 15.3 120 Positions are for equinox of date
Star training set for 4007_Euryalos, (2026/04/20 04:23UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 16.73 136 4Gam Crv 12:15:48.1 -17:32:30 2.6 13.88 123 PPM 195518 12:27:51.4 -04:36:55 6.2 1.15 121 PPM 195499 12:27:01.0 -03:32:08 8.4 0.70 120 PPM 195457 12:25:04.3 -04:02:34 9.7 0.26 120 4007_Euryalos 12:24:29.0 -03:49:35 15.3 120 Positions are for J2000