RECON: TNO occultation with 181855

Event between (181855) 98WT31 and star GA1360:03523547 with event index number of 1806774

Geocentric closest approach at 2027/12/26 13:15:22 UTC

J2000 position of star is 05:55:36.3 +46:02:28
Equinox of date position of star is 05:57:24.0 +46:02:35
Stellar brightness G=15.2, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 159 degrees from the moon. Moon is 2% illuminated.
Apparent brightness V=23.5

[RECON map]
Object is 37.7 AU from the Sun and 36.8 AU from the Earth.
Apparent velocity is 25.2 km/sec on the sky relative to the star, or, 3.4 arcsec/hr.
The 1-sigma error in the time of the event is 558 seconds.
The 1-sigma cross-track error in the shadow position is 5926 km.
The sky-plane scale is 26673.7 km/arcsec.

The object has an absolute magnitude Hv=7.7
Diameter=173.8 km assuming a 5% albedo -- 6.9 sec chord
Diameter=70.9 km assuming a 30% albedo -- 2.8 sec chord
Dynamical classification is SCATEXTD
 
 
 
 
 
 

Star training set for 181855, (2027/12/26 13:15UT)
Object            RA         Dec     mag  sep  mel
Pollux         07:47:01.8 +27:57:23  1.1 28.10 147
34Bet Aur      06:01:35.0 +44:56:49  1.9  1.29 160
35Pi Aur       06:02:00.8 +45:56:09  5.9  0.76 159
PPM 048591     05:59:42.0 +45:54:08  7.2  0.38 159
PPM 048565     05:58:06.6 +45:59:16  9.7  0.09 159
181855         05:57:41.1 +46:02:36 15.2       159
Positions are for equinox of date

This table contains the target star visibility for the RECON network. The observing range has been set to a maximum of 1.6 sigma about the mid-time.
The median site spacing is 16.5 km RECON observability=0.9 and success probability=7.0%
Site Site mid-time
(UT)
Sun alt
(deg)
Sky Moon Star alt
(deg)
Star az
(deg)
Target Observing Time
(UT)
X-track
(km)
Sleaford 13:12:53 -16.9 AT Down 30.5 307.2 Up 12:57:53 - 13:27:53 -3952
Dunrhomin 13:12:16 -12.8 AT Down 22.6 312.0 Low 12:57:16 - 13:27:16 -4434
Nikitin 13:12:16 -12.8 AT Down 22.5 312.1 Low 12:57:16 - 13:27:16 -4444
CU-SBO 13:12:16 -12.8 AT Down 22.5 312.1 Low 12:57:16 - 13:27:16 -4452
Kelowna 13:12:45 -24.8 Dark Down 36.3 300.9 Up 12:57:45 - 13:27:45 -4738
Kamloops 13:12:48 -25.5 Dark Down 37.2 300.0 Up 12:57:48 - 13:27:48 -4740
Peachland 13:12:44 -25.0 Dark Down 36.4 300.9 Up 12:57:44 - 13:27:44 -4760
Penticton 13:12:44 -24.9 Dark Down 36.2 301.1 Up 12:57:44 - 13:27:44 -4761
Summerland 13:12:44 -24.9 Dark Down 36.3 301.0 Up 12:57:44 - 13:27:44 -4763
Anarchist Mountain Observatory 13:12:42 -24.7 Dark Down 35.8 301.5 Up 12:57:42 - 13:27:42 -4780
Oliver 13:12:42 -24.8 Dark Down 36.0 301.3 Up 12:57:42 - 13:27:42 -4781
Okanogan 13:12:40 -24.7 Dark Down 35.6 301.8 Up 12:57:40 - 13:27:40 -4828
Brewster 13:12:39 -24.8 Dark Down 35.6 301.9 Up 12:57:39 - 13:27:39 -4854
Manson/Chelan 13:12:38 -25.0 Dark Down 35.7 301.8 Up 12:57:38 - 13:27:38 -4886
Wenatchee 13:12:37 -25.1 Dark Down 35.5 302.0 Up 12:57:37 - 13:27:37 -4922
PNWRO 13:12:32 -23.9 Dark Down 34.0 303.5 Up 12:57:32 - 13:27:32 -4925
Ellensburg 13:12:36 -25.2 Dark Down 35.4 302.2 Up 12:57:36 - 13:27:36 -4958
Yakima 13:12:34 -25.1 Dark Down 35.2 302.4 Up 12:57:34 - 13:27:34 -4983
Toppenish/White Swan 13:12:33 -25.0 Dark Down 35.0 302.6 Up 12:57:33 - 13:27:33 -4987
Victoria 13:12:42 -27.3 Dark Down 37.9 299.8 Up 12:57:42 - 13:27:42 -5022
The Dalles 13:12:31 -25.4 Dark Down 35.1 302.7 Up 12:57:31 - 13:27:31 -5077
Maupin 13:12:30 -25.3 Dark Down 34.8 303.0 Up 12:57:30 - 13:27:30 -5097
Bend 13:12:27 -25.3 Dark Down 34.3 303.5 Up 12:57:27 - 13:27:27 -5178
Sisters 13:12:27 -25.5 Dark Down 34.6 303.3 Up 12:57:27 - 13:27:27 -5179
Oregon Observatory 13:12:26 -25.4 Dark Down 34.3 303.6 Up 12:57:26 - 13:27:26 -5197
George/Scottsdale 13:11:57 -15.8 AT Down 22.3 311.4 Low 12:56:57 - 13:26:57 -5230
Patrick 13:12:01 -17.9 AT Down 24.6 310.2 Low 12:57:01 - 13:27:01 -5257
Cedarville 13:12:19 -24.1 Dark Down 32.2 305.3 Up 12:57:19 - 13:27:19 -5269
Chiloquin 13:12:22 -25.5 Dark Down 33.8 304.1 Up 12:57:22 - 13:27:22 -5304
Laughlin/Bullhead City 13:12:00 -18.4 Dark Down 24.9 310.1 Low 12:57:00 - 13:27:00 -5319
Klamath Falls 13:12:21 -25.4 Dark Down 33.6 304.3 Up 12:57:21 - 13:27:21 -5321
Lake Havasu City 13:11:59 -18.0 Dark Down 24.3 310.4 Low 12:56:59 - 13:26:59 -5345
Beatty 13:12:05 -20.6 Dark Down 27.4 308.7 Low 12:57:05 - 13:27:05 -5351
Hawthorne 13:12:10 -22.4 Dark Down 29.5 307.3 Low 12:57:10 - 13:27:10 -5366
Yerington 13:12:11 -22.9 Dark Down 30.1 306.9 Up 12:57:11 - 13:27:11 -5369
Fall River/Burney 13:12:18 -24.9 Dark Down 32.7 305.1 Up 12:57:18 - 13:27:18 -5374
Reno 13:12:13 -23.5 Dark Down 30.9 306.4 Up 12:57:13 - 13:27:13 -5374
Carson City 13:12:12 -23.4 Dark Down 30.6 306.6 Up 12:57:12 - 13:27:12 -5396
Portola 13:12:14 -24.0 Dark Down 31.4 306.1 Up 12:57:14 - 13:27:14 -5397
Gimple 13:12:15 -24.4 Dark Down 31.9 305.8 Up 12:57:15 - 13:27:15 -5400
Greenville 13:12:15 -24.4 Dark Down 31.9 305.7 Up 12:57:15 - 13:27:15 -5405
Gardnerville 13:12:11 -23.3 Dark Down 30.5 306.8 Up 12:57:11 - 13:27:11 -5409
Quincy 13:12:14 -24.4 Dark Down 31.8 305.8 Up 12:57:14 - 13:27:14 -5418
Bishop 13:12:07 -21.9 Dark Down 28.7 307.9 Low 12:57:07 - 13:27:07 -5426
Lee Vining 13:12:09 -22.6 Dark Down 29.5 307.4 Low 12:57:09 - 13:27:09 -5433
Yuma 13:11:55 -17.8 AT Down 23.4 310.9 Low 12:56:55 - 13:26:55 -5482
Calipatria 13:11:55 -18.6 Dark Down 24.2 310.5 Low 12:56:55 - 13:26:55 -5514
Idyllwild 13:11:57 -19.7 Dark Down 25.3 309.9 Low 12:56:57 - 13:26:57 -5553
Wildwood 13:11:59 -21.3 Dark Down 26.8 309.2 Low 12:56:59 - 13:26:59 -5655

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 181855, (2027/12/26 13:15UT)
Object            RA         Dec     mag  sep  mel
Pollux         07:45:17.9 +28:01:33  1.1 28.10 147
34Bet Aur      05:59:31.6 +44:56:51  1.9  1.29 160
35Pi Aur       05:59:56.1 +45:56:12  5.9  0.76 159
PPM 048591     05:57:37.4 +45:54:04  7.2  0.38 159
PPM 048565     05:56:01.9 +45:59:09  9.7  0.09 159
181855         05:55:36.3 +46:02:28 15.2       159
Positions are for J2000

Event circumstances last updated at 2024/02/25 04:11:42 UT

Marc W. Buie, Southwest Research Institute

RECON