RECON: TNO occultation with 118378

Event between (118378) 99HT11 and star GA0700:06142655 with event index number of 1376490

Geocentric closest approach at 2025/07/13 14:25:12 UTC

J2000 position of star is 16:03:58.7 -18:36:49
Equinox of date position of star is 16:05:22.7 -18:40:43
Stellar brightness G=16.9, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 82 degrees from the moon. Moon is 92% illuminated.
Apparent brightness V=23.3

Object is 39.4 AU from the Sun and 38.7 AU from the Earth.
Apparent velocity is 14.5 km/sec on the sky relative to the star, or, 1.9 arcsec/hr.
The 1-sigma error in the time of the event is 540 seconds.
The 1-sigma cross-track error in the shadow position is 3108 km.

The object has an absolute magnitude Hv=7.3
Diameter=182.0 km assuming a 5% albedo -- 14.7 sec chord
Diameter=74.3 km assuming a 30% albedo -- 6.0 sec chord
Dynamical classification is 7:4EEE
 
 
 
 
 
 
 
 

Star training set for 118378, (2025/07/13 14:25UT)
Object            RA         Dec     mag  sep  mel
Antares        16:30:58.6 -26:29:11  0.9  9.77  75
8Bet1Sco       16:06:55.5 -19:52:24  2.6  1.24  82
8Bet2Sco       16:06:56.0 -19:52:10  5.1  1.24  82
PPM 231166     16:06:31.4 -18:36:28  6.7  0.26  82
PPM 231156     16:06:02.1 -18:27:34 10.0  0.26  82
118378         16:05:27.3 -18:40:56 16.9        82
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, (2025/07/13 14:25UT)
Object            RA         Dec     mag  sep  mel
Antares        16:29:24.4 -26:25:56  0.9  9.77  75
8Bet1Sco       16:05:26.2 -19:48:20  2.6  1.24  82
8Bet2Sco       16:05:26.7 -19:48:07  5.1  1.24  82
PPM 231166     16:05:02.8 -18:32:23  6.7  0.26  82
PPM 231156     16:04:33.6 -18:23:28 10.0  0.26  82
118378         16:03:58.7 -18:36:49 16.9        82
Positions are for J2000

Event circumstances last updated at 2024/03/21 22:30:05 UT

Marc W. Buie, Southwest Research Institute

RECON