Occultation event with (17171) 99NB38, event index number 707
Regions able to see the event: Senegal
Geocentric closest approach at 2025/02/24 20:10:13 UTC
J2000 position of star is 00:40:40.5 +27:43:43
Equinox of date position of star is 00:42:01.0 +27:51:59
Star is 88 degrees from the moon. Moon is 13% illuminated.
Stellar brightness G=11.9, apparent brightess of occulting body is G=16.2
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
Expected flux drop is 2% with SNR of 23.4 per integration
Apparent velocity is 34.8 km/sec on the sky relative to the star, or, 30.8 arcsec/hr.
The recommended exposure time corresponds to 4.2 km per image.
The 1-sigma error in the time of the event is 1.2 seconds.
The 1-sigma cross-track error in the shadow position is 32.2 km.
The sky-plane scale is 4060.8 km/arcsec.
Diameter estimates:
45.9 km assuming a 5% albedo, aximum of 1.3 sec for a central chord
18.8 km assuming a 30% albedo, maximum of 0.5 sec for a central chord
Cross-track diameter of 45.9 km used for deployment plan.
Star training set for 17171_99NB38, (2025/02/24 20:10UT) Object RA Dec mag sep mel Deneb 20:42:17.4 +45:22:16 1.3 49.92 72 Algenib 00:14:32.1 +15:19:24 2.8 14.07 76 PPM 089965 00:37:40.3 +27:23:34 6.2 1.07 87 PPM 090048 00:42:46.0 +28:10:49 8.2 0.35 88 PPM 090036 00:42:00.9 +27:52:00 11.9 0.00 88 17171_99NB38 00:42:01.0 +27:51:59 16.2 88 Positions are for equinox of date
Star training set for 17171_99NB38, (2025/02/24 20:10UT) Object RA Dec mag sep mel Deneb 20:41:25.9 +45:16:49 1.3 49.92 72 Algenib 00:13:14.2 +15:11:00 2.8 14.07 76 PPM 089965 00:36:20.1 +27:15:17 6.2 1.07 87 PPM 090048 00:41:25.4 +28:02:33 8.2 0.35 88 PPM 090036 00:40:40.4 +27:43:44 11.9 0.00 88 17171_99NB38 00:40:40.5 +27:43:43 16.2 88 Positions are for J2000