RECON: TNO occultation with 609221

Event between (609221) 04VC131 and star GA1100:00668374 with event index number of 2789227

Geocentric closest approach at 2025/12/04 02:25:15 UTC

J2000 position of star is 04:32:44.7 +21:30:34
Equinox of date position of star is 04:34:10.3 +21:33:32
Stellar brightness G=0.0, use SENSEUP=2 with the MallinCam and and exposure time of 125 milli-seconds with the QHY174 camera.
Star is 11 degrees from the moon. Moon is 99% illuminated.
Apparent brightness V=22.2

[RECON map]
Object is 41.0 AU from the Sun and 40.0 AU from the Earth.
Apparent velocity is 25.3 km/sec on the sky relative to the star, or, 3.1 arcsec/hr.
The 1-sigma error in the time of the event is 78 seconds.
The 1-sigma cross-track error in the shadow position is 1468 km.
The sky-plane scale is 28987.1 km/arcsec.

The object has an absolute magnitude Hv=6.1
Diameter=351.6 km assuming a 5% albedo -- 14.4 sec chord
Diameter=143.5 km assuming a 30% albedo -- 5.9 sec chord
Dynamical classification is CLASSICAL
 
 
 
 
 
 

Star training set for 609221, (2025/12/04 02:25UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:37:24.7 +16:33:34  0.8  5.06  14
3Iot Aur       04:58:41.2 +33:12:17  2.7 12.83  18
PPM 093535     04:29:33.3 +21:40:32  5.9  1.11  10
PPM 093627     04:37:50.3 +21:44:24  8.5  0.84  12
PPM 093580     04:33:27.3 +21:41:22  9.0  0.23  11
PPM 093590     04:34:30.3 +21:28:26 10.7  0.10  11
609221         04:34:17.1 +21:33:46  0.0        12
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 5.0 sigma about the mid-time.
The median site spacing is 24.0 km RECON observability=1.0 and success probability=73.9%
Site Site mid-time
(UT)
Sun alt
(deg)
Sky Moon Star alt
(deg)
Star az
(deg)
Target Observing Time
(UT)
X-track
(km)
Kamloops 02:27:26 -22.6 Dark Up 23.6 84.4 Low 02:20:26 - 02:34:27 1290
Victoria 02:27:35 -20.3 Dark Up 21.4 81.3 Low 02:20:35 - 02:34:36 1245
Peachland 02:27:29 -22.9 Dark Up 23.9 84.5 Low 02:20:29 - 02:34:30 1218
Kelowna 02:27:29 -23.1 Dark Up 24.1 84.7 Low 02:20:28 - 02:34:29 1216
Summerland 02:27:30 -22.9 Dark Up 24.0 84.5 Low 02:20:30 - 02:34:31 1206
Penticton 02:27:30 -23.0 Dark Up 24.0 84.5 Low 02:20:30 - 02:34:31 1199
Oliver 02:27:31 -22.9 Dark Up 24.0 84.4 Low 02:20:31 - 02:34:32 1177
Anarchist Mountain Observatory 02:27:32 -23.0 Dark Up 24.1 84.4 Low 02:20:32 - 02:34:33 1162
Okanogan 02:27:34 -22.8 Dark Up 23.9 84.0 Low 02:20:34 - 02:34:35 1127
Brewster 02:27:35 -22.6 Dark Up 23.8 83.7 Low 02:20:35 - 02:34:36 1116
Manson/Chelan 02:27:36 -22.4 Dark Up 23.5 83.4 Low 02:20:36 - 02:34:37 1113
Wenatchee 02:27:38 -22.2 Dark Up 23.3 83.1 Low 02:20:38 - 02:34:39 1088
Ellensburg 02:27:39 -22.0 Dark Up 23.1 82.7 Low 02:20:39 - 02:34:40 1068
Yakima 02:27:41 -21.9 Dark Up 23.1 82.6 Low 02:20:41 - 02:34:42 1042
Toppenish/White Swan 02:27:42 -22.0 Dark Up 23.2 82.6 Low 02:20:41 - 02:34:42 1023
The Dalles 02:27:45 -21.3 Dark Up 22.5 81.7 Low 02:20:44 - 02:34:45 995
Sleaford 02:27:11 -31.6 Dark Up 32.6 96.5 Up 02:20:10 - 02:34:11 987
Maupin 02:27:46 -21.3 Dark Up 22.5 81.6 Low 02:20:46 - 02:34:47 964
PNWRO 02:27:42 -22.9 Dark Up 24.2 83.5 Low 02:20:42 - 02:34:43 954
Sisters 02:27:49 -20.8 Dark Up 22.1 81.0 Low 02:20:49 - 02:34:50 921
Bend 02:27:50 -20.9 Dark Up 22.2 81.0 Low 02:20:49 - 02:34:50 897
Oregon Observatory 02:27:51 -20.8 Dark Up 22.1 80.9 Low 02:20:50 - 02:34:51 889
Chiloquin 02:27:55 -20.3 Dark Up 21.6 80.1 Low 02:20:55 - 02:34:56 811
Klamath Falls 02:27:57 -20.2 Dark Up 21.6 80.0 Low 02:20:56 - 02:34:57 785
Fall River/Burney 02:28:00 -20.3 Dark Up 21.7 79.8 Low 02:21:00 - 02:35:01 689
Cedarville 02:27:58 -21.3 Dark Up 22.7 80.7 Low 02:20:58 - 02:34:59 684
Greenville 02:28:03 -20.4 Dark Up 21.9 79.7 Low 02:21:02 - 02:35:03 608
Gimple 02:28:03 -20.5 Dark Up 21.9 79.8 Low 02:21:02 - 02:35:03 606
Quincy 02:28:03 -20.4 Dark Up 21.8 79.7 Low 02:21:03 - 02:35:04 593
Portola 02:28:04 -20.7 Dark Up 22.2 79.9 Low 02:21:03 - 02:35:04 569
Reno 02:28:04 -21.2 Dark Up 22.6 80.2 Low 02:21:04 - 02:35:05 527
Carson City 02:28:05 -21.1 Dark Up 22.6 80.0 Low 02:21:05 - 02:35:06 500
Gardnerville 02:28:06 -21.1 Dark Up 22.6 80.0 Low 02:21:06 - 02:35:07 480
Yerington 02:28:06 -21.5 Dark Up 23.0 80.3 Low 02:21:05 - 02:35:06 464
Hawthorne 02:28:07 -21.9 Dark Up 23.4 80.4 Low 02:21:06 - 02:35:07 411
Lee Vining 02:28:09 -21.4 Dark Up 22.9 79.9 Low 02:21:08 - 02:35:09 385
Bishop 02:28:10 -21.8 Dark Up 23.4 80.1 Low 02:21:10 - 02:35:11 313
Beatty 02:28:10 -23.0 Dark Up 24.6 80.8 Low 02:21:10 - 02:35:11 221
Dunrhomin 02:27:48 -32.3 Dark Up 33.8 89.4 Up 02:20:48 - 02:34:49 96
Nikitin 02:27:49 -32.3 Dark Up 33.8 89.2 Up 02:20:49 - 02:34:50 82
CU-SBO 02:27:49 -32.2 Dark Up 33.8 89.1 Up 02:20:49 - 02:34:50 79
Wildwood 02:28:20 -21.0 Dark Up 22.6 78.6 Low 02:21:19 - 02:35:20 60
Laughlin/Bullhead City 02:28:14 -24.4 Dark Up 26.1 81.1 Low 02:21:13 - 02:35:14 4
Patrick 02:28:13 -25.0 Dark Up 26.7 81.6 Low 02:21:12 - 02:35:13 0
Idyllwild 02:28:20 -22.4 Dark Up 24.1 79.4 Low 02:21:19 - 02:35:20 -37
Lake Havasu City 02:28:16 -24.5 Dark Up 26.2 80.9 Low 02:21:15 - 02:35:16 -60
Calipatria 02:28:20 -23.3 Dark Up 25.0 79.7 Low 02:21:20 - 02:35:21 -131
Yuma 02:28:21 -23.9 Dark Up 25.6 79.9 Low 02:21:20 - 02:35:21 -200
George/Scottsdale 02:28:15 -26.4 Dark Up 28.1 81.7 Low 02:21:15 - 02:35:16 -214

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 609221, (2025/12/04 02:25UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:35:55.3 +16:30:29  0.8  5.06  14
3Iot Aur       04:56:59.6 +33:09:58  2.7 12.83  18
PPM 093535     04:28:00.9 +21:37:10  5.9  1.11  10
PPM 093627     04:36:17.7 +21:41:20  8.5  0.84  12
PPM 093580     04:31:54.8 +21:38:09  9.0  0.23  11
PPM 093590     04:32:57.9 +21:25:15 10.7  0.10  11
609221         04:32:44.7 +21:30:34  0.0        11
Positions are for J2000

Event circumstances last updated at 2024/01/08 05:17:35 UT

Marc W. Buie, Southwest Research Institute

RECON