Occultation event with (5254) Ulysses, event index number 3865
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/07/19 23:58:14 UTC
J2000 position of star is 12:21:02.7 +20:56:20
Equinox of date position of star is 12:22:23.1 +20:47:30
Star is 28 degrees from the moon. Moon is 35% illuminated.
Stellar brightness G=15.5, apparent brightess of occulting body is G=15.2
Use an exposure time of 0.65 seconds with the standard RECON-QHY system.
SNR of 5.1 per integration for unocculted signal
Expected flux drop is 44% with SNR of 2.2 for the occulted depth (per occulted point)
Apparent velocity is 29.2 km/sec on the sky relative to the star, or, 24.4 arcsec/hr.
Position angle of asteroid motion is 135.2 degrees
The recommended exposure time corresponds to 19.0 km per image.
The 1-sigma error in the time of the event is 1.3 seconds.
The 1-sigma cross-track error in the shadow position is 10.4 km.
The sky-plane scale is 4299.2 km/arcsec.
Diameter estimates:
87.5 km assuming a 5% albedo, maximum of 3.0 sec for a central chord
35.7 km assuming a 30% albedo, maximum of 1.2 sec for a central chord
Cross-track diameter of 76.1 km used for deployment plan.
Star training set for 5254_Ulysses, (2026/07/19 23:58UT) Object RA Dec mag sep mel Arcturus 14:16:52.5 +19:02:45 0.0 26.93 37 Denebola 11:50:24.8 +14:25:25 2.1 9.93 24 20 Com 12:31:03.1 +20:44:58 5.7 2.03 28 PPM 101837 12:23:05.4 +21:43:33 7.8 0.95 29 PPM 101835 12:22:59.7 +21:09:15 9.1 0.39 29 PPM 101816 12:21:35.5 +20:57:39 10.7 0.25 28 5254_Ulysses 12:22:23.1 +20:47:30 15.2 28 Positions are for equinox of date
Star training set for 5254_Ulysses, (2026/07/19 23:58UT) Object RA Dec mag sep mel Arcturus 14:15:37.7 +19:10:06 0.0 26.93 37 Denebola 11:49:02.7 +14:34:16 2.1 9.93 24 20 Com 12:29:43.3 +20:53:45 5.7 2.03 28 PPM 101837 12:21:45.1 +21:52:22 7.8 0.95 29 PPM 101835 12:21:39.4 +21:18:05 9.1 0.39 29 PPM 101816 12:20:15.1 +21:06:29 10.7 0.25 28 5254_Ulysses 12:21:02.7 +20:56:20 15.2 28 Positions are for J2000