RECON: TNO occultation with 307261

Event between (307261) 02MS4 and star GA0840:16049938 with event index number of 2185273

Geocentric closest approach at 2025/10/26 03:17:33 UTC

J2000 position of star is 19:07:43.1 -05:32:56
Equinox of date position of star is 19:09:00.4 -05:30:34
Stellar brightness G=16.8, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 33 degrees from the moon. Moon is 18% illuminated.
Apparent brightness V=20.4

[RECON map]
Object is 46.1 AU from the Sun and 46.3 AU from the Earth.
Apparent velocity is 14.7 km/sec on the sky relative to the star, or, 1.6 arcsec/hr.
The 1-sigma error in the time of the event is 256 seconds.
The 1-sigma cross-track error in the shadow position is 2148 km.
The sky-plane scale is 33572.4 km/arcsec.

The object has an absolute magnitude Hv=3.6
Diameter=1066.6 km assuming a 5% albedo -- 77.6 sec chord
Diameter=435.5 km assuming a 30% albedo -- 31.7 sec chord
Dynamical classification is SCATEXTD
 
 
 
 
 
 

Star training set for 307261, (2025/10/26 03:17UT)
Object            RA         Dec     mag  sep  mel
Antares        16:30:59.7 -26:29:13  0.9 43.11  13
Tarazed        19:47:29.2 +10:40:40  2.7 18.80  51
16Lam Aql      19:07:37.1 -04:50:30  3.4  0.76  33
PPM 202573     19:09:36.9 -05:17:24  8.5  0.25  33
307261         19:09:05.7 -05:30:24 16.8        33
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 3.5 sigma about the mid-time.
The median site spacing is 8.9 km RECON observability=1.0 and success probability=9.7%
Site Site mid-time
(UT)
Sun alt
(deg)
Sky Moon Star alt
(deg)
Star az
(deg)
Target Observing Time
(UT)
X-track
(km)
Sleaford 03:18:07 -32.5 Dark Down 17.8 234.8 Really Low 03:03:07 - 03:33:07 2548
Kamloops 03:17:26 -24.2 Dark Down 25.5 221.4 Low 03:02:26 - 03:32:26 2246
Kelowna 03:17:35 -24.9 Dark Down 25.7 222.6 Low 03:02:35 - 03:32:35 2237
Peachland 03:17:34 -24.7 Dark Down 25.9 222.3 Low 03:02:34 - 03:32:34 2227
Summerland 03:17:36 -24.8 Dark Down 26.0 222.4 Low 03:02:36 - 03:32:36 2224
Penticton 03:17:36 -24.9 Dark Down 26.0 222.6 Low 03:02:36 - 03:32:36 2224
Oliver 03:17:38 -25.0 Dark Down 26.2 222.7 Low 03:02:38 - 03:32:38 2211
Anarchist Mountain Observatory 03:17:39 -25.1 Dark Down 26.3 223.0 Low 03:02:39 - 03:32:39 2209
Okanogan 03:17:42 -25.1 Dark Down 26.8 223.0 Low 03:02:42 - 03:32:42 2179
Brewster 03:17:43 -25.0 Dark Down 27.1 222.9 Low 03:02:43 - 03:32:43 2165
Manson/Chelan 03:17:43 -24.8 Dark Down 27.4 222.6 Low 03:02:43 - 03:32:43 2148
Wenatchee 03:17:44 -24.8 Dark Down 27.9 222.6 Low 03:02:44 - 03:32:44 2126
Dunrhomin 03:19:20 -37.3 Dark Down 23.6 239.5 Low 03:04:20 - 03:34:20 2125
Nikitin 03:19:22 -37.3 Dark Down 23.7 239.5 Low 03:04:22 - 03:34:22 2116
CU-SBO 03:19:22 -37.3 Dark Down 23.8 239.5 Low 03:04:22 - 03:34:22 2112
Ellensburg 03:17:46 -24.7 Dark Down 28.3 222.5 Low 03:02:46 - 03:32:46 2104
PNWRO 03:17:56 -26.0 Dark Down 28.2 224.6 Low 03:02:56 - 03:32:56 2101
Victoria 03:17:26 -22.5 Dark Down 28.4 219.0 Low 03:02:26 - 03:32:26 2098
Yakima 03:17:47 -24.7 Dark Down 28.6 222.6 Low 03:02:47 - 03:32:47 2087
Toppenish/White Swan 03:17:49 -24.9 Dark Down 28.6 222.9 Low 03:02:49 - 03:32:49 2082
The Dalles 03:17:49 -24.4 Dark Down 29.6 222.4 Low 03:02:49 - 03:32:49 2030
Maupin 03:17:52 -24.6 Dark Down 29.8 222.7 Low 03:02:52 - 03:32:52 2014
Sisters 03:17:55 -24.3 Dark Down 30.7 222.5 Up 03:02:55 - 03:32:55 1963
Bend 03:17:57 -24.5 Dark Down 30.8 222.9 Up 03:02:57 - 03:32:57 1959
Oregon Observatory 03:17:57 -24.5 Dark Down 30.9 222.8 Up 03:02:57 - 03:32:57 1947
Chiloquin 03:18:02 -24.3 Dark Up 32.1 223.0 Up 03:03:02 - 03:33:02 1874
Cedarville 03:18:09 -25.7 Dark Down 32.0 225.2 Up 03:03:09 - 03:33:09 1868
Klamath Falls 03:18:05 -24.4 Dark Up 32.3 223.2 Up 03:03:05 - 03:33:05 1860
Fall River/Burney 03:18:09 -24.8 Dark Up 33.0 224.2 Up 03:03:09 - 03:33:09 1811
Hawthorne 03:18:09 -27.2 Dark Up 33.2 228.1 Up 03:03:09 - 03:33:09 1797
Yerington 03:18:09 -26.7 Dark Up 33.2 227.3 Up 03:03:09 - 03:33:09 1794
Reno 03:18:09 -26.1 Dark Up 33.2 226.4 Up 03:03:09 - 03:33:09 1792
Gimple 03:18:09 -25.3 Dark Up 33.3 225.1 Up 03:03:09 - 03:33:09 1783
Portola 03:18:09 -25.6 Dark Up 33.3 225.7 Up 03:03:09 - 03:33:09 1782
Greenville 03:18:09 -25.2 Dark Up 33.4 225.0 Up 03:03:09 - 03:33:09 1781
Carson City 03:18:09 -26.2 Dark Up 33.4 226.6 Up 03:03:09 - 03:33:09 1778
Quincy 03:18:09 -25.2 Dark Up 33.5 225.1 Up 03:03:09 - 03:33:09 1772
Gardnerville 03:18:09 -26.3 Dark Up 33.5 226.8 Up 03:03:09 - 03:33:09 1770
Lee Vining 03:18:09 -26.8 Dark Up 33.8 227.9 Up 03:03:09 - 03:33:09 1758
Beatty 03:18:53 -28.9 Dark Up 33.0 230.8 Up 03:03:53 - 03:33:53 1708
Patrick 03:19:14 -31.5 Dark Down 32.0 234.3 Up 03:04:14 - 03:34:14 1694
Bishop 03:18:44 -27.6 Dark Up 33.7 229.0 Up 03:03:44 - 03:33:44 1692
Laughlin/Bullhead City 03:19:12 -31.0 Dark Up 32.6 233.8 Up 03:04:12 - 03:34:12 1663
George/Scottsdale 03:19:33 -33.4 Dark Down 31.5 236.9 Up 03:04:33 - 03:34:33 1642
Lake Havasu City 03:19:17 -31.3 Dark Up 32.8 234.4 Up 03:04:17 - 03:34:17 1630
Idyllwild 03:19:09 -29.3 Dark Up 34.9 232.6 Up 03:04:09 - 03:34:09 1525
Calipatria 03:19:20 -30.4 Dark Up 34.4 234.0 Up 03:04:20 - 03:34:20 1517
Yuma 03:19:25 -31.2 Dark Up 34.0 235.1 Up 03:04:25 - 03:34:25 1513
Wildwood 03:19:00 -27.7 Dark Up 35.9 230.6 Up 03:04:00 - 03:34:00 1496

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 307261, (2025/10/26 03:17UT)
Object            RA         Dec     mag  sep  mel
Antares        16:29:24.4 -26:25:56  0.9 43.11  13
Tarazed        19:46:15.6 +10:36:48  2.7 18.80  51
16Lam Aql      19:06:14.9 -04:52:59  3.4  0.76  33
PPM 202573     19:08:14.4 -05:19:58  8.5  0.25  33
307261         19:07:43.1 -05:32:56 16.8        33
Positions are for J2000

Event circumstances last updated at 2024/03/03 06:04:36 UT

Marc W. Buie, Southwest Research Institute

RECON