RECON: TNO occultation with 78799

Event between (78799) 02XW93 and star GA1240:02825523 with event index number of 2436593

Geocentric closest approach at 2025/12/25 16:38:47 UTC

J2000 position of star is 06:39:56.4 +34:42:34
Equinox of date position of star is 06:41:32.8 +34:41:08
Stellar brightness G=15.4, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 119 degrees from the moon. Moon is 28% illuminated.
Apparent brightness V=21.5

Object is 46.3 AU from the Sun and 45.3 AU from the Earth.
Apparent velocity is 26.4 km/sec on the sky relative to the star, or, 2.9 arcsec/hr.
The 1-sigma error in the time of the event is 181 seconds.
The 1-sigma cross-track error in the shadow position is 1690 km.

The object has an absolute magnitude Hv=4.9
Diameter=605.4 km assuming a 5% albedo -- 23.9 sec chord
Diameter=247.1 km assuming a 30% albedo -- 9.7 sec chord
Dynamical classification is CENTAURR
 
 
 
 
 
 
 
 

Star training set for 78799, (2025/12/25 16:41UT)
Object            RA         Dec     mag  sep  mel
Pollux         07:46:54.3 +27:57:41  1.1 15.44 135
34Bet Aur      06:01:26.2 +44:56:50  1.9 12.82 110
PPM 071742     06:34:08.9 +32:26:03  6.0  2.74 118
PPM 071969     06:44:17.2 +34:04:10  7.9  0.82 120
PPM 071944     06:43:17.4 +34:49:58  9.4  0.37 120
PPM 071912     06:41:22.4 +34:47:19 10.1  0.12 119
78799          06:41:40.0 +34:41:02 15.4       120
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 78799, (2025/12/25 16:41UT)
Object            RA         Dec     mag  sep  mel
Pollux         07:45:17.9 +28:01:33  1.1 15.44 135
34Bet Aur      05:59:31.6 +44:56:51  1.9 12.82 110
PPM 071742     06:32:27.1 +32:27:18  6.0  2.74 118
PPM 071969     06:42:34.2 +34:05:48  7.9  0.82 120
PPM 071944     06:41:33.8 +34:51:34  9.4  0.37 120
PPM 071912     06:39:38.8 +34:48:51 10.1  0.12 119
78799          06:39:56.4 +34:42:34 15.4       119
Positions are for J2000

Event circumstances last updated at 2024/03/04 05:37:36 UT

Marc W. Buie, Southwest Research Institute

RECON