RECON: TNO occultation with 517717

Event between (517717) 15KZ120 and star GA1360:01866368 with event index number of 2628229

Geocentric closest approach at 2025/12/16 20:34:07 UTC

J2000 position of star is 03:52:54.4 +47:48:47
Equinox of date position of star is 03:54:33.3 +47:52:46
Stellar brightness G=14.6, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 153 degrees from the moon. Moon is 9% illuminated.
TNO apparent brightness V=21.9

TNO is 14.9 AU from the Sun and 14.0 AU from the Earth.
The TNO is moving 30.4 km/sec on the sky relative to the star, or, 10.8 arcsec/hr.
The 1-sigma error in the time of the event is 100 seconds.
The 1-sigma cross-track error in the shadow position is 3584 km.

The TNO has an absolute magnitude Hv=10.1
Diameter=57.5 km assuming a 5% albedo -- 1.8 sec chord
Diameter=23.5 km assuming a 30% albedo -- 0.8 sec chord
Dynamical classification is CENTAURR
 
 
 
 
 
 
 
 

Star training set for 517717, (2025/12/16 20:34UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:37:24.8 +16:33:34  0.8 32.53 158
Mirphak        03:26:11.4 +49:57:05  1.8  5.13 152
PPM 046639     03:57:51.0 +47:56:43  5.2  0.52 152
PPM 046626     03:56:34.5 +47:43:46  8.5  0.34 153
PPM 046603     03:54:30.5 +47:42:50  9.4  0.18 153
517717         03:54:46.9 +47:53:19 14.6       152
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 517717, (2025/12/16 20:34UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:35:55.3 +16:30:29  0.8 32.53 158
Mirphak        03:24:19.4 +49:51:40  1.8  5.13 152
PPM 046639     03:55:58.2 +47:52:16  5.2  0.52 152
PPM 046626     03:54:42.0 +47:39:17  8.5  0.34 153
PPM 046603     03:52:38.2 +47:38:18  9.4  0.18 153
517717         03:52:54.4 +47:48:47 14.6       153
Positions are for J2000

Event circumstances last updated at 2022/10/30 02:03:38 UT

Marc W. Buie, Southwest Research Institute

RECON