RECON: TNO occultation with 120178

Event between (120178) 03OP32 and star GA0920:18103519 with event index number of 2139175

Geocentric closest approach at 2025/06/03 18:27:13 UTC

J2000 position of star is 23:08:15.5 +02:44:46
Equinox of date position of star is 23:09:28.5 +02:52:33
Stellar brightness G=16.4, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 172 degrees from the moon. Moon is 56% illuminated.
Apparent brightness V=20.5

Object is 43.0 AU from the Sun and 43.1 AU from the Earth.
Apparent velocity is 7.6 km/sec on the sky relative to the star, or, 0.9 arcsec/hr.
The 1-sigma error in the time of the event is 242 seconds.
The 1-sigma cross-track error in the shadow position is 1944 km.

The object has an absolute magnitude Hv=4.0
Diameter=933.3 km assuming a 5% albedo -- 124.5 sec chord
Diameter=381.0 km assuming a 30% albedo -- 50.8 sec chord
Dynamical classification is SCATEXTD
 
 
 
 
 
 
 
 

Star training set for 120178, (2025/06/03 18:25UT)
Object            RA         Dec     mag  sep  mel
Fomalhaut      22:59:02.9 -29:29:12  1.2 32.47 154
Markab         23:06:01.7 +15:20:33  2.5 12.49 160
5 Psc          23:09:59.0 +02:16:00  5.4  0.63 173
PPM 173800     23:10:40.4 +02:16:58  8.0  0.66 173
PPM 173815     23:11:29.0 +03:04:20  9.5  0.52 172
PPM 173768     23:08:45.3 +03:00:50 10.2  0.24 172
120178         23:09:33.3 +02:53:03 16.4       172
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 120178, (2025/06/03 18:25UT)
Object            RA         Dec     mag  sep  mel
Fomalhaut      22:57:39.6 -29:37:24  1.2 32.47 154
Markab         23:04:45.8 +15:12:18  2.5 12.49 160
5 Psc          23:08:41.1 +02:07:43  5.4  0.63 173
PPM 173800     23:09:22.5 +02:08:40  8.0  0.66 173
PPM 173815     23:10:11.2 +02:56:03  9.5  0.52 172
PPM 173768     23:07:27.5 +02:52:34 10.2  0.24 172
120178         23:08:15.5 +02:44:46 16.4       172
Positions are for J2000

Event circumstances last updated at 2023/11/18 04:55:52 UT

Marc W. Buie, Southwest Research Institute

RECON