Occultation event with (12242) Koon, event index number 4722
Regions able to see the event: Japan
Geocentric closest approach at 2026/11/16 16:52:01 UTC
J2000 position of star is 06:12:28.8 -01:46:00
Equinox of date position of star is 06:13:50.3 -01:46:31
Star is 132 degrees from the moon. Moon is 43% illuminated.
Stellar brightness G=16.0, apparent brightess of occulting body is G=16.2
Use an exposure time of 0.55 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 54% with SNR of 1.6 for the occulted depth (per occulted point)
Apparent velocity is 16.7 km/sec on the sky relative to the star, or, 18.0 arcsec/hr.
Position angle of asteroid motion is 46.0 degrees
The recommended exposure time corresponds to 9.2 km per image.
The 1-sigma error in the time of the event is 0.8 seconds.
The 1-sigma cross-track error in the shadow position is 30.3 km.
The sky-plane scale is 3335.1 km/arcsec.
Diameter estimates:
39.8 km assuming a 5% albedo, maximum of 2.4 sec for a central chord
16.2 km assuming a 30% albedo, maximum of 1.0 sec for a central chord
Cross-track diameter of 37.9 km used for deployment plan.
Star training set for 12242_Koon, (2026/11/16 16:52UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.7 +07:24:35 0.4 10.14 131 Saiph 05:49:01.9 -09:39:44 2.1 10.01 123 PPM 176187 06:16:56.3 -00:31:28 6.2 1.47 133 PPM 176172 06:14:58.1 -01:49:56 8.3 0.29 132 PPM 176165 06:14:09.8 -01:39:00 9.7 0.15 132 12242_Koon 06:13:50.3 -01:46:31 16.2 132 Positions are for equinox of date
This table contains the target star visibility for registered Japan sites that are relevant for this occultation. This list has been filtered to only those sites that can see the field and are within range of the shadow given the uncertainties. The observing time range has been calculated to cover the time of the event at each site with allowances for the event timing uncertainty plus time for obtaining a pre and post event baseline lightcurve. This set of stations has a 66.3 % chance of getting at least one chord. There is a 0.0% chance of 2 or more chords assuming clear weather for all.
| Site Name | Site mid-time (UT) |
Sun alt (deg) |
Sky | Moon | Star alt (deg) |
Star az (deg) |
Target | Observing Time | Xtrack (km) |
Prob |
|---|---|---|---|---|---|---|---|---|---|---|
| Kumamoto | 16:50:41 | -62.0 | Dark | Down | 53.0 | 156.4 | Up | 16:46:47-16:52:47 | 194.6 | 0.000 | Sapporo | 16:49:20 | -50.3 | Dark | Down | 45.1 | 174.8 | Up | 16:46:54-16:52:54 | 135.0 | 0.000 | Kagoshima | 16:50:46 | -62.5 | Dark | Down | 54.1 | 155.5 | Up | 16:47:38-16:53:38 | 134.8 | 0.000 | Akita | 16:49:37 | -52.5 | Dark | Down | 48.3 | 172.7 | Up | 16:47:46-16:53:46 | 21.5 | 0.330 | Niigata | 16:49:47 | -53.9 | Dark | Down | 50.0 | 170.9 | Up | 16:47:41-16:53:41 | -20.2 | 0.333 | Tokyo | 16:49:54 | -54.2 | Dark | Down | 52.2 | 171.5 | Up | 16:46:37-16:52:37 | -187.1 | 0.000 |
Star training set for 12242_Koon, (2026/11/16 16:52UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 10.14 131 Saiph 05:47:45.4 -09:40:11 2.1 10.01 123 PPM 176187 06:15:34.0 -00:30:50 6.2 1.47 133 PPM 176172 06:13:36.6 -01:49:22 8.3 0.29 132 PPM 176165 06:12:48.2 -01:38:28 9.7 0.15 132 12242_Koon 06:12:28.8 -01:46:00 16.2 132 Positions are for J2000