RECON: TNO occultation with 181874

Event between (181874) 99HW11 and star GA0800:04920104 with event index number of 1300579

Geocentric closest approach at 2024/04/07 19:56:50 UTC

J2000 position of star is 15:52:57.3 -08:49:30
Equinox of date position of star is 15:54:13.7 -08:53:37
Stellar brightness G=15.1, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 127 degrees from the moon. Moon is 1% illuminated.
Apparent brightness V=23.5

Object is 46.3 AU from the Sun and 45.6 AU from the Earth.
Apparent velocity is 18.8 km/sec on the sky relative to the star, or, 2.0 arcsec/hr.
The 1-sigma error in the time of the event is 539 seconds.
The 1-sigma cross-track error in the shadow position is 4218 km.

The object has an absolute magnitude Hv=6.8
Diameter=239.9 km assuming a 5% albedo -- 13.7 sec chord
Diameter=97.9 km assuming a 30% albedo -- 5.6 sec chord
Dynamical classification is SCATNEAR
 
 
 
 
 
 
 
 

Star training set for 181874, (2024/04/07 20:04UT)
Object            RA         Dec     mag  sep  mel
Antares        16:30:54.0 -26:29:01  0.9 19.61 115
1Del Oph       16:15:37.2 -03:45:18  2.7  7.39 122
50 Lib         16:02:06.4 -08:28:42  5.5  1.98 125
PPM 199054     15:55:06.8 -08:20:58  8.2  0.58 127
PPM 199047     15:54:39.2 -08:40:34  9.3  0.24 127
181874         15:54:16.2 -08:53:45 15.1       127
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 181874, (2024/04/07 20:04UT)
Object            RA         Dec     mag  sep  mel
Antares        16:29:24.4 -26:25:56  0.9 19.61 115
1Del Oph       16:14:20.7 -03:41:43  2.7  7.39 122
50 Lib         16:00:47.6 -08:24:41  5.5  1.98 125
PPM 199054     15:53:48.1 -08:16:44  8.2  0.58 127
PPM 199047     15:53:20.4 -08:36:20  9.3  0.24 127
181874         15:52:57.3 -08:49:30 15.1       127
Positions are for J2000

Event circumstances last updated at 2023/07/04 04:09:55 UT

Marc W. Buie, Southwest Research Institute

RECON