RECON: TNO occultation with 181855

Event between (181855) 98WT31 and star GA1340:03326982 with event index number of 1641302

Geocentric closest approach at 2026/12/13 08:41:46 UTC

J2000 position of star is 05:47:56.2 +45:25:44
Equinox of date position of star is 05:49:35.1 +45:26:06
Stellar brightness G=15.7, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 136 degrees from the moon. Moon is 16% illuminated.
TNO apparent brightness V=23.5

[RECON map]
TNO is 37.7 AU from the Sun and 36.7 AU from the Earth.
The TNO is moving 25.3 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 492 seconds.
The 1-sigma cross-track error in the shadow position is 5346 km.
The sky-plane scale is 26653.0 km/arcsec.

The TNO 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, (2026/12/13 08:42UT)
Object            RA         Dec     mag  sep  mel
Pollux         07:46:57.9 +27:57:32  1.1 28.98 164
34Bet Aur      06:01:30.4 +44:56:50  1.9  2.10 138
35Pi Aur       06:01:56.2 +45:56:10  5.9  2.16 137
PPM 048461     05:50:43.0 +45:14:37  8.0  0.24 136
PPM 048442     05:49:05.3 +45:24:30  9.7  0.15 135
181855         05:49:55.6 +45:26:10 15.7       136
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 1.8 sigma about the mid-time.
The median site spacing is 28.7 km RECON observability=1.0 and success probability=11.3%
Site Site mid-time
(UT)
Sun alt
(deg)
Sky Moon Star alt
(deg)
Star az
(deg)
Target Observing Time
(UT)
X-track
(km)
Sleaford 08:41:00 -55.0 Dark Down 75.6 250.1 Up 08:26:00 - 08:56:00 -1133
Kamloops 08:41:36 -61.1 Dark Down 83.7 215.0 Up 08:26:36 - 08:56:36 -1524
Kelowna 08:41:33 -61.6 Dark Down 84.0 224.6 Up 08:26:33 - 08:56:33 -1603
Peachland 08:41:34 -61.8 Dark Down 84.2 223.8 Up 08:26:34 - 08:56:34 -1619
Summerland 08:41:33 -61.9 Dark Down 84.3 225.3 Up 08:26:33 - 08:56:33 -1634
Penticton 08:41:33 -61.9 Dark Down 84.3 226.4 Up 08:26:33 - 08:56:33 -1640
Oliver 08:41:33 -62.2 Dark Down 84.5 229.0 Up 08:26:33 - 08:56:33 -1678
Anarchist Mountain Observatory 08:41:32 -62.3 Dark Down 84.5 231.4 Up 08:26:32 - 08:56:32 -1695
Tonasket 08:41:32 -62.6 Dark Down 84.8 233.6 Up 08:26:32 - 08:56:32 -1729
Okanogan 08:41:32 -63.0 Dark Down 85.0 236.0 Up 08:26:32 - 08:56:32 -1768
Victoria 08:41:43 -63.8 Dark Down 86.6 205.4 Up 08:26:43 - 08:56:43 -1791
Brewster 08:41:33 -63.3 Dark Down 85.3 237.6 Up 08:26:33 - 08:56:33 -1800
Manson/Chelan 08:41:34 -63.6 Dark Down 85.6 237.9 Up 08:26:34 - 08:56:34 -1827
Wenatchee 08:41:33 -64.0 Dark Down 85.9 242.6 Up 08:26:33 - 08:56:33 -1881
Ellensburg 08:41:34 -64.5 Dark Down 86.3 247.0 Up 08:26:34 - 08:56:34 -1929
Yakima 08:41:34 -64.9 Dark Down 86.4 252.9 Up 08:26:34 - 08:56:34 -1974
Toppenish/White Swan 08:41:33 -65.0 Dark Down 86.4 256.8 Up 08:26:33 - 08:56:33 -1996
PNWRO 08:41:29 -64.9 Dark Down 85.4 265.2 Up 08:26:29 - 08:56:29 -2017
Goldendale 08:41:34 -65.6 Dark Down 86.7 264.8 Up 08:26:34 - 08:56:34 -2062
The Dalles 08:41:35 -65.9 Dark Down 87.0 268.3 Up 08:26:35 - 08:56:35 -2091
Maupin 08:41:35 -66.3 Dark Down 86.9 276.2 Up 08:26:35 - 08:56:35 -2135
Sisters 08:41:35 -67.2 Dark Down 87.0 293.7 Up 08:26:35 - 08:56:35 -2238
Bend 08:41:35 -67.4 Dark Down 86.8 296.4 Up 08:26:35 - 08:56:35 -2261
Oregon Observatory 08:41:35 -67.6 Dark Down 86.8 299.8 Up 08:26:35 - 08:56:35 -2282
North Lake 08:41:32 -68.0 Dark Down 86.1 305.4 Up 08:26:32 - 08:56:32 -2346
Dunrhomin 08:40:41 -61.9 Dark Down 74.4 296.1 Up 08:25:41 - 08:55:41 -2353
CU-SBO 08:40:41 -62.1 Dark Down 74.4 296.9 Up 08:25:41 - 08:55:41 -2382
Chiloquin 08:41:35 -68.9 Dark Down 86.1 319.1 Up 08:26:35 - 08:56:35 -2431
Lakeview 08:41:30 -68.7 Dark Down 85.1 313.2 Up 08:26:30 - 08:56:30 -2455
Klamath Falls 08:41:35 -69.2 Dark Down 85.8 321.6 Up 08:26:35 - 08:56:35 -2468
Cedarville 08:41:29 -69.2 Dark Down 84.5 317.4 Up 08:26:29 - 08:56:29 -2525
Fall River/Burney 08:41:33 -70.1 Dark Down 84.7 327.4 Up 08:26:33 - 08:56:33 -2593
Susanville 08:41:30 -70.3 Dark Down 83.9 326.6 Up 08:26:30 - 08:56:30 -2653
Gimple 08:41:30 -70.7 Dark Down 83.7 329.1 Up 08:26:30 - 08:56:30 -2686
Greenville 08:41:31 -70.7 Dark Down 83.8 329.5 Up 08:26:31 - 08:56:31 -2687
Quincy 08:41:31 -70.9 Dark Down 83.6 330.5 Up 08:26:31 - 08:56:31 -2709
Portola 08:41:29 -70.8 Dark Down 83.3 328.6 Up 08:26:29 - 08:56:29 -2717
Reno 08:41:27 -70.7 Dark Down 82.8 326.8 Up 08:26:27 - 08:56:27 -2737
Carson City 08:41:27 -71.0 Dark Down 82.5 328.2 Up 08:26:27 - 08:56:27 -2776
Yerington 08:41:24 -70.9 Dark Down 82.1 326.3 Up 08:26:24 - 08:56:24 -2788
Gardnerville 08:41:26 -71.2 Dark Down 82.3 328.9 Up 08:26:26 - 08:56:26 -2802
Hawthorne 08:41:22 -71.0 Dark Down 81.5 326.1 Up 08:26:22 - 08:56:22 -2830
Tonopah 08:41:17 -70.6 Dark Down 80.4 323.1 Up 08:26:17 - 08:56:17 -2859
Lee Vining 08:41:24 -71.6 Dark Down 81.2 329.9 Up 08:26:24 - 08:56:24 -2899
Bishop 08:41:21 -71.7 Dark Down 80.4 329.2 Up 08:26:21 - 08:56:21 -2953
Beatty 08:41:15 -71.1 Dark Down 79.3 325.5 Up 08:26:15 - 08:56:15 -2976
Indian Springs 08:41:11 -70.7 Dark Down 78.5 323.6 Up 08:26:11 - 08:56:11 -2991
Henderson 08:41:08 -70.6 Dark Down 77.8 323.4 Up 08:26:08 - 08:56:08 -3035
Patrick 08:41:04 -70.2 Dark Down 76.7 322.5 Up 08:26:04 - 08:56:04 -3080
Kingman/Dolan Springs 08:41:04 -70.5 Dark Down 76.7 323.5 Up 08:26:04 - 08:56:04 -3107
Laughlin/Bullhead City 08:41:06 -70.8 Dark Down 76.9 324.7 Up 08:26:06 - 08:56:06 -3120
Mohave Valley 08:41:06 -71.0 Dark Down 76.7 325.4 Up 08:26:06 - 08:56:06 -3149
Lake Havasu City 08:41:05 -71.0 Dark Down 76.2 325.8 Up 08:26:05 - 08:56:05 -3187
George/Scottsdale 08:40:55 -69.7 Dark Down 74.4 322.6 Up 08:25:55 - 08:55:55 -3215
Parker 08:41:04 -71.2 Dark Down 75.9 326.5 Up 08:26:04 - 08:56:04 -3224
Wildwood 08:41:19 -74.1 Dark Down 77.5 337.4 Up 08:26:19 - 08:56:19 -3309
Idyllwild 08:41:12 -73.1 Dark Down 76.6 333.0 Up 08:26:12 - 08:56:12 -3315
Calipatria 08:41:08 -72.6 Dark Down 75.6 331.3 Up 08:26:08 - 08:56:08 -3357
Yuma 08:41:04 -72.2 Dark Down 74.8 330.1 Up 08:26:04 - 08:56:04 -3385

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, (2026/12/13 08:42UT)
Object            RA         Dec     mag  sep  mel
Pollux         07:45:17.9 +28:01:33  1.1 28.98 164
34Bet Aur      05:59:31.6 +44:56:51  1.9  2.10 138
35Pi Aur       05:59:56.1 +45:56:12  5.9  2.16 137
PPM 048461     05:48:43.9 +45:14:13  8.0  0.24 136
PPM 048442     05:47:06.0 +45:24:02  9.7  0.15 135
181855         05:47:56.2 +45:25:44 15.7       136
Positions are for J2000

Event circumstances last updated at 2022/04/25 23:03:46 UT

Marc W. Buie, Southwest Research Institute

RECON