RECON: TNO occultation with 181855

Event between (181855) 98WT31 and star GA1340:03228234 with event index number of 1478811

Geocentric closest approach at 2025/12/13 13:37:13 UTC

J2000 position of star is 05:38:42.0 +44:47:30
Equinox of date position of star is 05:40:29.5 +44:48:14
Stellar brightness G=13.9, use SENSEUP=64 with the MallinCam and and exposure time of 1 seconds with the QHY174 camera.
Star is 105 degrees from the moon. Moon is 34% illuminated.
Apparent brightness V=23.5

[RECON map]
Object is 37.6 AU from the Sun and 36.7 AU from the Earth.
Apparent velocity is 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 414 seconds.
The 1-sigma cross-track error in the shadow position is 4809 km.
The sky-plane scale is 26632.4 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, (2025/12/13 13:37UT)
Object            RA         Dec     mag  sep  mel
Pollux         07:46:54.2 +27:57:41  1.1 30.19  78
34Bet Aur      06:01:26.0 +44:56:50  1.9  3.69 101
PPM 048445     05:49:06.3 +42:32:01  6.3  2.74 103
PPM 048271     05:38:11.0 +44:47:04  8.3  0.43 105
PPM 048312     05:40:05.9 +44:42:48  9.4  0.13 105
181855         05:40:36.1 +44:48:16 13.9       104
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 2.2 sigma about the mid-time.
The median site spacing is 16.6 km RECON observability=0.8 and success probability=5.6%

Site	Site mid-time (UT)	Sun alt (deg)	Sky	Moon	Star alt (deg)	Star az (deg)	Target	Observing Time (UT)	X-track (km)
Sleaford	13:34:48	-12.7	AT	Up	30.9	304.6	Up	13:19:48 - 13:49:48	1057
Dunrhomin	13:34:10	-7.8	NT	Up	23.4	309.8	Low	13:19:10 - 13:49:10	572
Nikitin	13:34:09	-7.7	NT	Up	23.3	309.8	Low	13:19:09 - 13:49:09	561
CU-SBO	13:34:09	-7.7	NT	Up	23.3	309.8	Low	13:19:09 - 13:49:09	553
Kelowna	13:34:40	-20.3	Dark	Up	37.0	298.3	Up	13:19:40 - 13:49:40	285
Kamloops	13:34:43	-21.0	Dark	Up	37.9	297.3	Up	13:19:43 - 13:49:43	284
Peachland	13:34:40	-20.4	Dark	Up	37.1	298.2	Up	13:19:40 - 13:49:40	263
Penticton	13:34:39	-20.2	Dark	Up	36.9	298.5	Up	13:19:39 - 13:49:39	262
Summerland	13:34:39	-20.3	Dark	Up	37.0	298.4	Up	13:19:39 - 13:49:39	260
Anarchist Mountain Observatory	13:34:37	-20.0	Dark	Up	36.6	298.9	Up	13:19:37 - 13:49:37	243
Oliver	13:34:38	-20.2	Dark	Up	36.8	298.7	Up	13:19:38 - 13:49:38	242
Okanogan	13:34:35	-20.0	Dark	Up	36.4	299.2	Up	13:19:35 - 13:49:35	195
Brewster	13:34:34	-20.1	Dark	Up	36.4	299.3	Up	13:19:34 - 13:49:34	170
Manson/Chelan	13:34:34	-20.3	Dark	Up	36.5	299.2	Up	13:19:34 - 13:49:34	138
Wenatchee	13:34:32	-20.3	Dark	Up	36.4	299.5	Up	13:19:32 - 13:49:32	102
PNWRO	13:34:27	-19.0	Dark	Up	34.8	301.0	Up	13:19:27 - 13:49:27	98
Ellensburg	13:34:31	-20.4	Dark	Up	36.3	299.6	Up	13:19:31 - 13:49:31	66
Yakima	13:34:30	-20.3	Dark	Up	36.1	299.9	Up	13:19:30 - 13:49:30	41
Toppenish/White Swan	13:34:29	-20.1	Dark	Up	35.9	300.1	Up	13:19:29 - 13:49:29	38
Victoria	13:34:37	-22.5	Dark	Up	38.7	297.2	Up	13:19:37 - 13:49:37	5
The Dalles	13:34:27	-20.5	Dark	Up	36.0	300.2	Up	13:19:27 - 13:49:27	-52
Maupin	13:34:25	-20.3	Dark	Up	35.7	300.5	Up	13:19:25 - 13:49:25	-71
Sisters	13:34:22	-20.5	Dark	Up	35.6	300.8	Up	13:19:22 - 13:49:22	-153
Bend	13:34:22	-20.3	Dark	Up	35.3	301.1	Up	13:19:22 - 13:49:22	-153
Oregon Observatory	13:34:21	-20.3	Dark	Up	35.3	301.1	Up	13:19:21 - 13:49:21	-171
George/Scottsdale	13:33:50	-10.3	NT	Up	23.4	309.4	Low	13:18:50 - 13:48:50	-218
Patrick	13:33:54	-12.4	AT	Up	25.7	308.1	Low	13:18:54 - 13:48:54	-242
Cedarville	13:34:13	-18.9	Dark	Up	33.3	303.0	Up	13:19:13 - 13:49:13	-245
Chiloquin	13:34:17	-20.3	Dark	Up	34.9	301.7	Up	13:19:17 - 13:49:17	-278
Klamath Falls	13:34:16	-20.2	Dark	Up	34.6	302.0	Up	13:19:16 - 13:49:16	-295
Laughlin/Bullhead City	13:33:54	-12.9	AT	Up	26.0	307.9	Low	13:18:54 - 13:48:54	-303
Lake Havasu City	13:33:52	-12.4	AT	Up	25.5	308.3	Low	13:18:52 - 13:48:52	-329
Beatty	13:33:59	-15.1	AT	Up	28.5	306.5	Low	13:18:59 - 13:48:59	-331
Hawthorne	13:34:04	-16.9	AT	Up	30.6	305.1	Up	13:19:04 - 13:49:04	-343
Yerington	13:34:06	-17.5	AT	Up	31.2	304.7	Up	13:19:06 - 13:49:06	-346
Fall River/Burney	13:34:12	-19.6	Dark	Up	33.8	302.8	Up	13:19:12 - 13:49:12	-348
Reno	13:34:07	-18.1	Dark	Up	32.0	304.2	Up	13:19:07 - 13:49:07	-350
Carson City	13:34:06	-18.0	AT	Up	31.7	304.4	Up	13:19:06 - 13:49:06	-372
Portola	13:34:08	-18.7	Dark	Up	32.5	303.8	Up	13:19:08 - 13:49:08	-372
Gimple	13:34:09	-19.0	Dark	Up	32.9	303.5	Up	13:19:09 - 13:49:09	-375
Greenville	13:34:10	-19.1	Dark	Up	33.0	303.5	Up	13:19:10 - 13:49:10	-380
Gardnerville	13:34:05	-17.9	AT	Up	31.6	304.5	Up	13:19:05 - 13:49:05	-385
Quincy	13:34:09	-19.0	Dark	Up	32.9	303.6	Up	13:19:09 - 13:49:09	-393
Bishop	13:34:01	-16.4	AT	Up	29.8	305.7	Low	13:19:01 - 13:49:01	-404
Lee Vining	13:34:03	-17.2	AT	Up	30.6	305.2	Up	13:19:03 - 13:49:03	-410
Yuma	13:33:47	-12.1	AT	Up	24.6	308.8	Low	13:18:47 - 13:48:47	-466
Calipatria	13:33:49	-12.9	AT	Up	25.4	308.4	Low	13:18:49 - 13:48:49	-497
Idyllwild	13:33:51	-14.1	AT	Up	26.6	307.8	Low	13:18:51 - 13:48:51	-534
Wildwood	13:33:52	-15.7	AT	Up	28.0	307.1	Low	13:18:52 - 13:48:52	-634

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, (2025/12/13 13:37UT)
Object            RA         Dec     mag  sep  mel
Pollux         07:45:17.9 +28:01:33  1.1 30.19  78
34Bet Aur      05:59:31.6 +44:56:51  1.9  3.69 101
PPM 048445     05:47:14.7 +42:31:34  6.3  2.74 103
PPM 048271     05:36:17.0 +44:46:12  8.3  0.43 105
PPM 048312     05:38:11.9 +44:42:01  9.4  0.13 105
181855         05:38:42.0 +44:47:30 13.9       105
Positions are for J2000

Event circumstances last updated at 2024/06/10 01:52:32 UT

RECON