RECON: TNO occultation with 12HL85

Event between 12HL85 and star GA0720:05372025 with event index number of 1134105

Geocentric closest approach at 2021/05/04 22:23:05 UTC

J2000 position of star is 15:01:43.7 -17:12:46
Equinox of date position of star is 15:02:55.5 -17:17:45
Stellar brightness G=17.0, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 100 degrees from the moon. Moon is 39% illuminated.
TNO apparent brightness V=22.6

TNO is 41.0 AU from the Sun and 40.0 AU from the Earth.
The TNO is moving 25.1 km/sec on the sky relative to the star, or, 3.1 arcsec/hr.
The 1-sigma error in the time of the event is 141 seconds.
The 1-sigma cross-track error in the shadow position is 2686 km.

The TNO has an absolute magnitude Hv=6.5
Diameter=296.5 km assuming a 5% albedo -- 11.8 sec chord
Diameter=121.0 km assuming a 30% albedo -- 4.8 sec chord
Dynamical classification is SCATEXTD
 
 
 
 
 
 
 
 

Star training set for 12HL85, (2021/05/04 22:23UT)
Object            RA         Dec     mag  sep  mel
Antares        16:30:43.2 -26:28:39  0.9 22.29  78
27Bet Lib      15:18:09.5 -09:27:37  2.6  8.67  99
21Nu Lib       15:07:49.3 -16:20:18  5.2  1.51  99
PPM 229686     15:04:18.7 -17:42:57  7.2  0.53 100
PPM 229643     15:02:41.0 -17:06:55  8.9  0.19 100
12HL85         15:02:55.6 -17:17:46 17.0       100
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 12HL85, (2021/05/04 22:23UT)
Object            RA         Dec     mag  sep  mel
Antares        16:29:24.4 -26:25:56  0.9 22.29  78
27Bet Lib      15:17:00.3 -09:22:59  2.6  8.67  99
21Nu Lib       15:06:37.6 -16:15:25  5.2  1.51  99
PPM 229686     15:03:06.5 -17:38:00  7.2  0.53 100
PPM 229643     15:01:29.1 -17:01:56  8.9  0.19 100
12HL85         15:01:43.7 -17:12:46 17.0       100
Positions are for J2000

Event circumstances last updated at 2021/04/21 22:32:14 UT

Marc W. Buie, Southwest Research Institute

RECON