Occultation event with (11552) Boucolion, event index number 1561
Regions able to see the event: US,RECON
Geocentric closest approach at 2025/11/21 08:01:59 UTC
J2000 position of star is 04:40:12.8 +05:05:27
Equinox of date position of star is 04:41:35.3 +05:08:22
Star is 158 degrees from the moon. Moon is 1% illuminated.
Stellar brightness G=16.2, apparent brightess of occulting body is G=15.1
Use an exposure time of 0.80 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 27% with SNR of 0.8 for the occulted depth (per occulted point)
Apparent velocity is 17.3 km/sec on the sky relative to the star, or, 19.3 arcsec/hr.
Position angle of asteroid motion is 81.2 degrees
The recommended exposure time corresponds to 13.8 km per image.
The 1-sigma error in the time of the event is 0.7 seconds.
The 1-sigma cross-track error in the shadow position is 28.6 km.
The sky-plane scale is 3220.0 km/arcsec.
Diameter estimates:
57.3 km assuming a 5% albedo, aximum of 3.3 sec for a central chord
23.4 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 51.1 km used for deployment plan.
Star training set for 11552_Boucolion, (2025/11/21 08:02UT) Object RA Dec mag sep mel Aldebaran 04:37:24.6 +16:33:33 0.8 11.47 170 Bellatrix 05:26:31.3 +06:22:15 1.6 11.24 156 PPM 147685 04:35:31.0 +05:37:16 5.8 1.59 159 PPM 147753 04:38:59.7 +05:01:59 7.4 0.65 158 PPM 147813 04:42:23.3 +05:15:58 10.0 0.24 158 11552_Boucolio 04:41:35.3 +05:08:22 15.1 158 Positions are for equinox of date
This table contains the target star visibility for registered US 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 0.0 % 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 |
|---|---|---|---|---|---|---|---|---|---|---|
This table contains the target star visibility for registered RECON 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 75.2 % chance of getting at least one chord. There is a 7.8% 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Chiloquin | 08:02:24 | -67.3 | Dark | Down | 51.3 | 162.7 | Up | 07:59:18-08:05:18 | 154.3 | 0.000 | Klamath Falls | 08:02:24 | -67.7 | Dark | Down | 51.7 | 162.7 | Up | 07:59:16-08:05:16 | 124.0 | 0.000 | Cedarville | 08:02:18 | -68.2 | Dark | Down | 52.7 | 165.0 | Up | 07:58:56-08:04:56 | 42.7 | 0.223 | Burney | 08:02:26 | -69.0 | Dark | Down | 53.0 | 162.4 | Up | 07:58:58-08:04:58 | 5.6 | 0.549 | Gimple | 08:02:23 | -69.7 | Dark | Down | 53.9 | 163.4 | Up | 07:58:58-08:04:58 | -69.5 | 0.047 | Quincy | 08:02:24 | -69.9 | Dark | Down | 54.0 | 163.2 | Up | 07:59:11-08:05:11 | -86.1 | 0.012 | Reno | 08:02:19 | -70.1 | Dark | Down | 54.7 | 164.9 | Up | 07:59:06-08:05:06 | -136.2 | 0.000 | Carson City | 08:02:19 | -70.4 | Dark | Down | 55.0 | 164.8 | Up | 07:59:01-08:05:01 | -168.5 | 0.000 | Gardnerville | 08:02:20 | -70.7 | Dark | Down | 55.3 | 164.8 | Up | 07:59:20-08:05:20 | -191.0 | 0.000 | Yerington | 08:02:17 | -70.5 | Dark | Down | 55.3 | 165.8 | Up | 07:59:23-08:05:23 | -194.7 | 0.000 | Swift | 08:02:30 | -71.3 | Dark | Down | 55.2 | 161.2 | Up | 07:59:04-08:05:04 | -198.1 | 0.000 |
Star training set for 11552_Boucolion, (2025/11/21 08:02UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 11.47 170 Bellatrix 05:25:07.8 +06:20:58 1.6 11.24 156 PPM 147685 04:34:08.2 +05:34:08 5.8 1.59 159 PPM 147753 04:37:37.3 +04:58:58 7.4 0.65 158 PPM 147813 04:41:00.7 +05:13:04 10.0 0.24 158 11552_Boucolio 04:40:12.8 +05:05:27 15.1 158 Positions are for J2000