RECON: TNO occultation with 181874

Event between (181874) 99HW11 and star GA0800:05035381 with event index number of 1882946

Geocentric closest approach at 2028/05/28 00:35:09 UTC

J2000 position of star is 16:08:43.7 -08:27:58
Equinox of date position of star is 16:10:00.2 -08:31:36
Stellar brightness G=14.3, use SENSEUP=64 with the MallinCam and and exposure time of 1 seconds with the QHY174 camera.
Star is 127 degrees from the moon. Moon is 16% illuminated.
Apparent brightness V=23.5

Object is 47.3 AU from the Sun and 46.3 AU from the Earth.
Apparent velocity is 25.0 km/sec on the sky relative to the star, or, 2.7 arcsec/hr.
The 1-sigma error in the time of the event is 666 seconds.
The 1-sigma cross-track error in the shadow position is 2193 km.

The object has an absolute magnitude Hv=6.8
Diameter=239.9 km assuming a 5% albedo -- 10.3 sec chord
Diameter=97.9 km assuming a 30% albedo -- 4.2 sec chord
Dynamical classification is SCATNEAR
 
 
 
 
 
 
 
 

Star training set for 181874, (2028/05/28 00:43UT)
Object            RA         Dec     mag  sep  mel
Antares        16:31:09.2 -26:29:33  0.9 18.62 136
1Del Oph       16:15:50.3 -03:45:54  2.7  4.97 126
16 Sco         16:13:39.8 -08:37:08  5.7  0.84 128
PPM 199341     16:10:33.7 -08:17:32  7.8  0.26 127
PPM 199337     16:10:22.0 -08:39:43  9.4  0.13 127
181874         16:10:16.1 -08:32:22 14.3       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, (2028/05/28 00:43UT)
Object            RA         Dec     mag  sep  mel
Antares        16:29:24.4 -26:25:56  0.9 18.62 136
1Del Oph       16:14:20.7 -03:41:43  2.7  4.97 126
16 Sco         16:12:07.4 -08:32:51  5.7  0.84 128
PPM 199341     16:09:01.5 -08:13:08  7.8  0.26 127
PPM 199337     16:08:49.5 -08:35:19  9.4  0.13 127
181874         16:08:43.7 -08:27:58 14.3       127
Positions are for J2000

Event circumstances last updated at 2023/07/07 03:10:15 UT

Marc W. Buie, Southwest Research Institute

RECON