RECON: TNO occultation with 121725

Event between (121725) Aphidas and star GA1040:03403514 with event index number of 1099060

Geocentric closest approach at 2021/06/01 12:57:47 UTC

J2000 position of star is 10:42:49.6 +14:10:00
Equinox of date position of star is 10:43:57.7 +14:03:15
Stellar brightness G=15.0, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 175 degrees from the moon. Moon is 58% illuminated.
TNO apparent brightness V=23.1

TNO is 25.0 AU from the Sun and 25.0 AU from the Earth.
The TNO is moving 6.7 km/sec on the sky relative to the star, or, 1.3 arcsec/hr.
The 1-sigma error in the time of the event is 177 seconds.
The 1-sigma cross-track error in the shadow position is 1292 km.

The TNO has an absolute magnitude Hv=8.9
Diameter=99.5 km assuming a 5% albedo -- 14.8 sec chord
Diameter=40.6 km assuming a 30% albedo -- 6.0 sec chord
Dynamical classification is CENTAURR
 
 
 
 
 
 
 
 

Star training set for 121725, (2021/06/01 12:58UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:09:30.6 +11:51:42  1.3  8.67 175
52 Leo         10:47:33.2 +14:04:52  5.5  0.87 174
PPM 127610     10:41:33.7 +14:51:04  8.1  0.99 176
PPM 127627     10:43:04.8 +13:38:42  8.7  0.46 175
PPM 127651     10:44:50.5 +14:07:19 11.2  0.22 175
121725         10:43:57.8 +14:03:14 15.0       175
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 121725, (2021/06/01 12:58UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:08:22.0 +11:58:02  1.3  8.67 175
52 Leo         10:46:25.1 +14:11:39  5.5  0.87 174
PPM 127610     10:40:25.2 +14:57:48  8.1  0.99 176
PPM 127627     10:41:56.6 +13:45:27  8.7  0.46 175
PPM 127651     10:43:42.3 +14:14:05 11.2  0.22 175
121725         10:42:49.6 +14:10:00 15.0       175
Positions are for J2000

Event circumstances last updated at 2021/05/19 01:05:37 UT

Marc W. Buie, Southwest Research Institute

RECON