RECON: TNO occultation with 120178

Event between (120178) 03OP32 and star GA0900:16477003 with event index number of 2139179

Geocentric closest approach at 2025/10/27 13:35:53 UTC

J2000 position of star is 23:01:34.3 +01:56:45
Equinox of date position of star is 23:02:47.4 +02:04:28
Stellar brightness G=13.3, use SENSEUP=32 with the MallinCam and and exposure time of 500 milli-seconds with the QHY174 camera.
Star is 68 degrees from the moon. Moon is 30% illuminated.
Apparent brightness V=20.4

Object is 43.1 AU from the Sun and 42.4 AU from the Earth.
Apparent velocity is 16.9 km/sec on the sky relative to the star, or, 2.0 arcsec/hr.
The 1-sigma error in the time of the event is 102 seconds.
The 1-sigma cross-track error in the shadow position is 1740 km.

The object has an absolute magnitude Hv=4.0
Diameter=933.3 km assuming a 5% albedo -- 56.4 sec chord
Diameter=381.0 km assuming a 30% albedo -- 23.0 sec chord
Dynamical classification is SCATEXTD
 
 
 
 
 
 
 
 

Star training set for 120178, (2025/10/27 13:36UT)
Object            RA         Dec     mag  sep  mel
Fomalhaut      22:59:04.2 -29:29:05  1.2 31.58  54
Markab         23:06:02.9 +15:20:41  2.5 13.28  76
2 Psc          23:00:46.9 +01:06:06  6.5  1.12  67
PPM 173643     23:02:01.8 +03:09:01  7.4  1.09  68
PPM 173658     23:02:56.1 +01:59:46  9.4  0.09  68
120178         23:02:53.4 +02:05:06 13.3        68
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, (2025/10/27 13:36UT)
Object            RA         Dec     mag  sep  mel
Fomalhaut      22:57:39.6 -29:37:24  1.2 31.58  54
Markab         23:04:45.8 +15:12:18  2.5 13.28  76
2 Psc          22:59:27.6 +00:57:46  6.5  1.12  67
PPM 173643     23:00:42.9 +03:00:40  7.4  1.09  68
PPM 173658     23:01:37.0 +01:51:25  9.4  0.09  68
120178         23:01:34.3 +01:56:45 13.3        68
Positions are for J2000

Event circumstances last updated at 2023/11/18 04:57:28 UT

Marc W. Buie, Southwest Research Institute

RECON