RECON: TNO occultation with 118378

Event between (118378) 99HT11 and star GA0700:06318299 with event index number of 1466309

Geocentric closest approach at 2026/03/29 05:57:27 UTC

J2000 position of star is 16:18:04.8 -19:19:44
Equinox of date position of star is 16:19:29.6 -19:23:12
Stellar brightness G=16.6, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 104 degrees from the moon. Moon is 85% illuminated.
Apparent brightness V=23.4

Object is 39.4 AU from the Sun and 38.8 AU from the Earth.
Apparent velocity is 10.5 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 1099 seconds.
The 1-sigma cross-track error in the shadow position is 5709 km.

The object has an absolute magnitude Hv=7.3
Diameter=182.0 km assuming a 5% albedo -- 20.2 sec chord
Diameter=74.3 km assuming a 30% albedo -- 8.3 sec chord
Dynamical classification is 7:4EEE
 
 
 
 
 
 
 
 

Star training set for 118378, (2026/03/29 05:57UT)
Object            RA         Dec     mag  sep  mel
Antares        16:31:01.2 -26:29:16  0.9  7.57 107
8Bet1Sco       16:06:58.0 -19:52:30  2.6  3.02 101
PPM 265352     16:18:31.5 -20:10:02  6.5  0.82 103
PPM 231502     16:20:20.4 -19:33:11  9.9  0.24 104
PPM 231486     16:19:49.3 -19:30:31 10.1  0.13 104
118378         16:19:36.7 -19:23:29 16.6       104
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 118378, (2026/03/29 05:57UT)
Object            RA         Dec     mag  sep  mel
Antares        16:29:24.4 -26:25:56  0.9  7.57 107
8Bet1Sco       16:05:26.2 -19:48:20  2.6  3.02 101
PPM 265352     16:16:59.2 -20:06:15  6.5  0.82 103
PPM 231502     16:18:48.4 -19:29:28  9.9  0.24 104
PPM 231486     16:18:17.4 -19:26:47 10.1  0.13 104
118378         16:18:04.8 -19:19:44 16.6       104
Positions are for J2000

Event circumstances last updated at 2024/03/21 22:30:50 UT

Marc W. Buie, Southwest Research Institute

RECON