RECON: TNO occultation with 531015

Event between (531015) 12BX154 and star GA0880:03956479 with event index number of 2439496

Geocentric closest approach at 2026/03/24 15:13:08 UTC

J2000 position of star is 11:38:15.3 -00:28:42
Equinox of date position of star is 11:39:24.0 -00:36:08
Stellar brightness G=10.6, use SENSEUP=4 with the MallinCam and and exposure time of 125 milli-seconds with the QHY174 camera.
Star is 97 degrees from the moon. Moon is 37% illuminated.
TNO apparent brightness V=23.0

TNO is 46.1 AU from the Sun and 45.1 AU from the Earth.
The TNO is moving 24.9 km/sec on the sky relative to the star, or, 2.7 arcsec/hr.
The 1-sigma error in the time of the event is 320 seconds.
The 1-sigma cross-track error in the shadow position is 5898 km.

The TNO has an absolute magnitude Hv=6.4
Diameter=316.2 km assuming a 5% albedo -- 12.8 sec chord
Diameter=129.1 km assuming a 30% albedo -- 5.2 sec chord
Dynamical classification is SCATNEAR
 
 
 
 
 
 
 
 

Star training set for 531015, (2026/03/24 15:27UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:09:46.0 +11:50:17  1.3 25.55  71
Denebola       11:50:23.9 +14:25:32  2.1 15.28  92
91Ups Leo      11:38:17.5 -00:58:08  4.3  0.48  97
PPM 178570     11:42:16.5 -00:49:12  7.8  0.70  97
PPM 178554     11:39:35.9 -00:37:25 10.0  0.00  97
531015         11:39:35.9 -00:37:25 10.6        97
Positions are for equinox of date

Azimuth is measured in degrees eastward from north. North is at an azimuth of 0, due East is at an azimuth of 90 degrees, due South is 180, and due West is 270.

Do not use the listing below for the RECON CPC 1100 telescopes. This is provided for other non-team facilities.

Star training set for 531015, (2026/03/24 15:27UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:08:21.9 +11:58:02  1.3 25.55  71
Denebola       11:49:02.8 +14:34:17  2.1 15.28  92
91Ups Leo      11:36:56.9 -00:49:25  4.3  0.48  97
PPM 178570     11:40:55.9 -00:40:28  7.8  0.70  97
PPM 178554     11:38:15.3 -00:28:41 10.0  0.00  97
531015         11:38:15.3 -00:28:42 10.6        97
Positions are for J2000

Event circumstances last updated at 2022/05/04 23:29:41 UT

Marc W. Buie, Southwest Research Institute

RECON