RECON: TNO occultation with 609221

Event between (609221) 04VC131 and star GA1100:00686558 with event index number of 2789223

Geocentric closest approach at 2025/10/26 04:19:23 UTC

J2000 position of star is 04:35:56.5 +21:37:12
Equinox of date position of star is 04:37:22.3 +21:40:03
Stellar brightness G=16.4, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 166 degrees from the moon. Moon is 19% illuminated.
Apparent brightness V=22.3

[RECON map]
Object is 40.9 AU from the Sun and 40.2 AU from the Earth.
Apparent velocity is 19.1 km/sec on the sky relative to the star, or, 2.4 arcsec/hr.
The 1-sigma error in the time of the event is 105 seconds.
The 1-sigma cross-track error in the shadow position is 1555 km.
The sky-plane scale is 29126.9 km/arcsec.

The object has an absolute magnitude Hv=6.1
Diameter=351.6 km assuming a 5% albedo -- 19.1 sec chord
Diameter=143.5 km assuming a 30% albedo -- 7.8 sec chord
Dynamical classification is CLASSICAL
 
 
 
 
 
 

Star training set for 609221, (2025/10/26 04:19UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:37:24.3 +16:33:33  0.8  5.11 163
3Iot Aur       04:58:40.7 +33:12:16  2.7 12.45 171
PPM 093646     04:39:47.4 +20:44:04  5.9  1.08 166
PPM 093627     04:37:49.9 +21:44:23  8.5  0.11 166
609221         04:37:28.7 +21:40:16 16.4       166
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 0.0 km RECON observability=0.1 and success probability=0.0%
Site Site mid-time
(UT)
Sun alt
(deg)
Sky Moon Star alt
(deg)
Star az
(deg)
Target Observing Time
(UT)
X-track
(km)
Kamloops 04:22:22 -34.0 Dark Down 17.2 76.7 Really Low 04:13:08 - 04:31:36 12131
Victoria 04:22:31 -33.0 Dark Down 14.8 73.9 Really Low 04:13:17 - 04:31:45 12095
Peachland 04:22:27 -34.7 Dark Down 17.4 76.8 Really Low 04:13:13 - 04:31:41 12066
Kelowna 04:22:28 -34.9 Dark Down 17.6 77.1 Really Low 04:13:14 - 04:31:42 12064
Summerland 04:22:28 -34.8 Dark Down 17.4 76.9 Really Low 04:13:14 - 04:31:42 12055
Penticton 04:22:28 -34.9 Dark Down 17.5 76.9 Really Low 04:13:14 - 04:31:42 12048
Oliver 04:22:30 -35.1 Dark Down 17.4 76.8 Really Low 04:13:16 - 04:31:44 12029
Anarchist Mountain Observatory 04:22:31 -35.3 Dark Down 17.5 76.9 Really Low 04:13:17 - 04:31:45 12014
Okanogan 04:22:33 -35.4 Dark Down 17.2 76.6 Really Low 04:13:19 - 04:31:47 11983
Brewster 04:22:36 -35.4 Dark Down 17.0 76.3 Really Low 04:13:22 - 04:31:50 11973
Manson/Chelan 04:22:36 -35.3 Dark Down 16.7 76.0 Really Low 04:13:22 - 04:31:50 11971
Wenatchee 04:22:38 -35.3 Dark Down 16.5 75.8 Really Low 04:13:24 - 04:31:52 11948
Ellensburg 04:22:41 -35.4 Dark Down 16.3 75.5 Really Low 04:13:27 - 04:31:55 11931
Yakima 04:22:42 -35.5 Dark Down 16.1 75.4 Really Low 04:13:28 - 04:31:56 11907
Toppenish/White Swan 04:22:43 -35.7 Dark Down 16.2 75.4 Really Low 04:13:29 - 04:31:57 11889
The Dalles 04:22:48 -35.5 Dark Down 15.5 74.7 Really Low 04:13:34 - 04:32:02 11865
Maupin 04:22:49 -35.7 Dark Down 15.4 74.7 Really Low 04:13:35 - 04:32:03 11837
Sleaford 04:22:11 -40.8 Dark Down 26.3 88.0 Low 04:12:57 - 04:31:25 11829
PNWRO 04:22:45 -36.8 Dark Down 17.1 76.4 Really Low 04:13:31 - 04:31:59 11824
Sisters 04:22:52 -35.7 Dark Down 14.9 74.1 Really Low 04:13:38 - 04:32:06 11797
Bend 04:22:55 -35.9 Dark Down 15.0 74.3 Really Low 04:13:41 - 04:32:09 11775
Oregon Observatory 04:22:54 -35.9 Dark Down 14.9 74.1 Really Low 04:13:40 - 04:32:08 11768
Chiloquin 04:23:00 -36.0 Dark Down 14.2 73.5 Really Low 04:13:46 - 04:32:14 11696
Klamath Falls 04:23:02 -36.2 Dark Down 14.2 73.5 Really Low 04:13:48 - 04:32:16 11671
Fall River/Burney 04:23:06 -36.8 Dark Down 14.1 73.5 Really Low 04:13:52 - 04:32:20 11582
Cedarville 04:23:06 -37.6 Dark Down 15.2 74.3 Really Low 04:13:52 - 04:32:20 11577
Greenville 04:23:13 -37.4 Dark Down 14.2 73.5 Really Low 04:13:59 - 04:32:27 11507
Gimple 04:23:13 -37.5 Dark Down 14.3 73.6 Really Low 04:13:59 - 04:32:27 11504
Quincy 04:23:13 -37.5 Dark Down 14.2 73.5 Really Low 04:13:59 - 04:32:27 11493
Portola 04:23:15 -37.9 Dark Down 14.5 73.7 Really Low 04:14:01 - 04:32:29 11469
Reno 04:23:13 -38.4 Dark Down 14.9 74.1 Really Low 04:13:59 - 04:32:27 11430
Carson City 04:23:16 -38.6 Dark Down 14.8 74.0 Really Low 04:14:02 - 04:32:30 11405
Gardnerville 04:23:17 -38.7 Dark Down 14.8 73.9 Really Low 04:14:03 - 04:32:31 11386
Yerington 04:23:18 -39.1 Dark Down 15.3 74.3 Really Low 04:14:04 - 04:32:32 11371
Hawthorne 04:23:19 -39.6 Dark Down 15.5 74.5 Really Low 04:14:05 - 04:32:33 11320
Lee Vining 04:23:21 -39.5 Dark Down 15.0 74.1 Really Low 04:14:07 - 04:32:35 11296
Bishop 04:23:25 -40.2 Dark Down 15.4 74.3 Really Low 04:14:11 - 04:32:39 11228
Beatty 04:23:27 -41.6 Dark Down 16.6 75.1 Really Low 04:14:13 - 04:32:41 11140
Dunrhomin 04:23:05 -48.4 Dark Down 26.0 82.9 Low 04:13:51 - 04:32:19 11004
Nikitin 04:23:06 -48.5 Dark Down 26.0 82.8 Low 04:13:52 - 04:32:20 10990
Wildwood 04:23:36 -40.9 Dark Down 14.4 73.4 Really Low 04:14:22 - 04:32:50 10989
CU-SBO 04:23:06 -48.4 Dark Down 25.9 82.7 Low 04:13:52 - 04:32:20 10988
Laughlin/Bullhead City 04:23:32 -43.8 Dark Down 17.9 75.7 Really Low 04:14:18 - 04:32:46 10933
Patrick 04:23:32 -44.3 Dark Down 18.5 76.2 Really Low 04:14:18 - 04:32:46 10928
Idyllwild 04:23:38 -42.5 Dark Down 15.8 74.2 Really Low 04:14:24 - 04:32:52 10897
Lake Havasu City 04:23:35 -44.2 Dark Down 17.9 75.6 Really Low 04:14:21 - 04:32:49 10872
Calipatria 04:23:41 -43.7 Dark Down 16.6 74.7 Really Low 04:14:27 - 04:32:55 10806
Yuma 04:23:42 -44.5 Dark Down 17.2 75.0 Really Low 04:14:28 - 04:32:56 10740
George/Scottsdale 04:23:37 -46.4 Dark Down 19.7 76.6 Really Low 04:14:23 - 04:32:51 10723

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, (2025/10/26 04:19UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:35:55.3 +16:30:29  0.8  5.11 163
3Iot Aur       04:56:59.6 +33:09:58  2.7 12.45 171
PPM 093646     04:38:15.8 +20:41:05  5.9  1.08 166
PPM 093627     04:36:17.7 +21:41:20  8.5  0.11 166
609221         04:35:56.5 +21:37:12 16.4       166
Positions are for J2000

Event circumstances last updated at 2024/01/08 05:16:26 UT

Marc W. Buie, Southwest Research Institute

RECON