RECON: TNO occultation with 13GB138

Event between 13GB138 and star GA0740:05331869 with event index number of 1642730

Geocentric closest approach at 2021/04/16 02:32:31 UTC

J2000 position of star is 15:00:59.6 -15:02:56
Equinox of date position of star is 15:02:09.8 -15:07:53
Stellar brightness G=15.1, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 157 degrees from the moon. Moon is 14% illuminated.
TNO apparent brightness V=23.8

TNO is 44.7 AU from the Sun and 43.8 AU from the Earth.
The TNO is moving 23.2 km/sec on the sky relative to the star, or, 2.6 arcsec/hr.
The 1-sigma error in the time of the event is 277 seconds.
The 1-sigma cross-track error in the shadow position is 2364 km.

The TNO has an absolute magnitude Hv=7.3
Diameter=208.0 km assuming a 5% albedo -- 9.0 sec chord
Diameter=84.9 km assuming a 30% albedo -- 3.7 sec chord
Dynamical classification is CLASSICAL
 
 
 
 
 
 
 
 

Star training set for 13GB138, (2021/04/16 02:33UT)
Object            RA         Dec     mag  sep  mel
Antares        16:30:43.0 -26:28:39  0.9 23.54 175
27Bet Lib      15:18:09.3 -09:27:37  2.6  6.88 158
21Nu Lib       15:07:49.1 -16:20:17  5.2  1.82 159
PPM 229632     15:02:06.5 -15:06:34  8.3  0.03 157
13GB138        15:02:10.5 -15:07:56 15.1       158
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 13GB138, (2021/04/16 02:33UT)
Object            RA         Dec     mag  sep  mel
Antares        16:29:24.4 -26:25:56  0.9 23.54 175
27Bet Lib      15:17:00.3 -09:22:59  2.6  6.88 158
21Nu Lib       15:06:37.6 -16:15:25  5.2  1.82 159
PPM 229632     15:00:55.6 -15:01:34  8.3  0.03 157
13GB138        15:00:59.6 -15:02:56 15.1       157
Positions are for J2000

Event circumstances last updated at 2021/01/20 20:30:14 UT

Marc W. Buie, Southwest Research Institute

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