RECON: TNO occultation with 581804

Event between (581804) 15KN167 and star GA0700:06690820 with event index number of 2544154

Geocentric closest approach at 2026/04/03 14:48:28 UTC

J2000 position of star is 16:41:02.8 -18:08:47
Equinox of date position of star is 16:42:19.6 -18:11:15
Stellar brightness G=15.9, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 41 degrees from the moon. Moon is 98% illuminated.
TNO apparent brightness V=24.8

TNO is 42.8 AU from the Sun and 42.3 AU from the Earth.
The TNO is moving 10.9 km/sec on the sky relative to the star, or, 1.3 arcsec/hr.
The 1-sigma error in the time of the event is 1939 seconds.
The 1-sigma cross-track error in the shadow position is 4999 km.

The TNO has an absolute magnitude Hv=8.4
Diameter=124.7 km assuming a 5% albedo -- 11.4 sec chord
Diameter=50.9 km assuming a 30% albedo -- 4.7 sec chord
Dynamical classification is 2:1E
 
 
 
 
 
 
 
 

Star training set for 581804, (2026/04/03 14:48UT)
Object            RA         Dec     mag  sep  mel
Antares        16:31:01.3 -26:29:16  0.9  8.71  38
35Eta Oph      17:11:53.1 -15:45:20  2.6  7.42  48
PPM 232030     16:43:05.7 -17:47:27  5.0  0.42  41
PPM 231954     16:40:00.3 -18:16:16  6.7  0.61  40
PPM 232017     16:42:43.6 -17:59:16  9.5  0.21  41
581804         16:42:34.4 -18:11:43 15.9        41
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 581804, (2026/04/03 14:48UT)
Object            RA         Dec     mag  sep  mel
Antares        16:29:24.4 -26:25:56  0.9  8.71  38
35Eta Oph      17:10:22.7 -15:43:29  2.6  7.42  48
PPM 232030     16:41:34.4 -17:44:32  5.0  0.42  41
PPM 231954     16:38:28.7 -18:13:14  6.7  0.61  40
PPM 232017     16:41:12.2 -17:56:21  9.5  0.21  41
581804         16:41:02.8 -18:08:47 15.9        41
Positions are for J2000

Event circumstances last updated at 2022/01/12 00:20:15 UT

Marc W. Buie, Southwest Research Institute

RECON