RECON: TNO occultation with 12HE85

Event between 12HE85 and star GA0700:33205388 with event index number of 1127586

Geocentric closest approach at 2021/07/22 21:46:41 UTC

J2000 position of star is 19:28:57.4 -19:15:55
Equinox of date position of star is 19:30:12.1 -19:13:12
Stellar brightness G=12.5, use SENSEUP=16 with the MallinCam and and exposure time of 250 milli-seconds with the QHY174 camera.
Star is 9 degrees from the moon. Moon is 98% illuminated.
TNO apparent brightness V=25.0

TNO is 40.4 AU from the Sun and 39.3 AU from the Earth.
The TNO is moving 24.0 km/sec on the sky relative to the star, or, 3.0 arcsec/hr.
The 1-sigma error in the time of the event is 459 seconds.
The 1-sigma cross-track error in the shadow position is 3016 km.

The TNO has an absolute magnitude Hv=9.0
Diameter=93.8 km assuming a 5% albedo -- 3.9 sec chord
Diameter=38.3 km assuming a 30% albedo -- 1.6 sec chord
Dynamical classification is 9:5EEEE
 
 
 
 
 
 
 
 

Star training set for 12HE85, (2021/07/22 21:47UT)
Object            RA         Dec     mag  sep  mel
Antares        16:30:44.0 -26:28:41  0.9 41.77  34
Nunki          18:56:36.0 -26:16:05  2.0 10.47   2
45Rho2Sgr      19:23:06.3 -18:16:00  5.8  1.93   9
PPM 236018     19:29:18.9 -19:17:51  8.1  0.23   9
PPM 236056     19:30:52.9 -19:12:49  9.8  0.16   9
12HE85         19:30:13.0 -19:13:10 12.5         9
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 12HE85, (2021/07/22 21:47UT)
Object            RA         Dec     mag  sep  mel
Antares        16:29:24.4 -26:25:56  0.9 41.77  34
Nunki          18:55:15.9 -26:17:49  2.0 10.47   2
45Rho2Sgr      19:21:51.1 -18:18:32  5.8  1.93   9
PPM 236018     19:28:03.3 -19:20:34  8.1  0.23   9
PPM 236056     19:29:37.4 -19:15:34  9.8  0.16   9
12HE85         19:28:57.4 -19:15:55 12.5         9
Positions are for J2000

Event circumstances last updated at 2021/04/21 22:33:04 UT

Marc W. Buie, Southwest Research Institute

RECON