Occultation event with (15527) 99YY2, event index number 970
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/05/14 01:15:28 UTC
J2000 position of star is 09:18:06.0 +06:14:28
Equinox of date position of star is 09:19:26.4 +06:08:00
Star is 107 degrees from the moon. Moon is 98% illuminated.
Stellar brightness G=15.9, apparent brightess of occulting body is G=17.2
Use an exposure time of 0.65 seconds with the standard RECON-QHY system.
SNR of 4.1 per integration for unocculted signal
Expected flux drop is 77% with SNR of 3.1 for the occulted depth (per occulted point)
Apparent velocity is 14.4 km/sec on the sky relative to the star, or, 12.0 arcsec/hr.
Position angle of asteroid motion is 11.7 degrees
The recommended exposure time corresponds to 9.3 km per image.
The 1-sigma error in the time of the event is 5.6 seconds.
The 1-sigma cross-track error in the shadow position is 16.6 km.
The sky-plane scale is 4317.0 km/arcsec.
Diameter estimates:
38.7 km assuming a 5% albedo, aximum of 2.7 sec for a central chord
15.8 km assuming a 30% albedo, maximum of 1.1 sec for a central chord
Cross-track diameter of 38.7 km used for deployment plan.
Star training set for 15527_99YY2, (2025/05/14 01:15UT) Object RA Dec mag sep mel Regulus 10:09:43.2 +11:50:32 1.3 13.66 99 PPM 155539 09:13:32.3 +03:45:42 6.0 2.79 108 PPM 155672 09:19:41.5 +06:57:56 8.4 0.83 108 PPM 155620 09:17:23.6 +06:00:29 9.8 0.52 108 PPM 155640 09:18:31.3 +05:51:08 10.6 0.36 107 15527_99YY2 09:19:26.4 +06:08:00 17.2 107 Positions are for equinox of date
Star training set for 15527_99YY2, (2025/05/14 01:15UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 13.66 99 PPM 155539 09:12:12.8 +03:52:01 6.0 2.79 108 PPM 155672 09:18:20.8 +07:04:24 8.4 0.83 108 PPM 155620 09:16:03.2 +06:06:54 9.8 0.52 108 PPM 155640 09:17:11.0 +05:57:34 10.6 0.36 107 15527_99YY2 09:18:06.0 +06:14:28 17.2 107 Positions are for J2000