Occultation event with (1208) Troilus, event index number 5024
Regions able to see the event: US,UVa
Geocentric closest approach at 2026/12/04 08:36:34 UTC
J2000 position of star is 05:18:23.0 +46:30:25
Equinox of date position of star is 05:20:23.1 +46:32:00
Star is 117 degrees from the moon. Moon is 20% illuminated.
Stellar brightness G=16.2, apparent brightess of occulting body is G=14.1
Use an exposure time of 1.25 seconds with the standard RECON-QHY system.
SNR of 3.4 per integration for unocculted signal
Expected flux drop is 12% with SNR of 0.4 for the occulted depth (per occulted point)
Apparent velocity is 20.0 km/sec on the sky relative to the star, or, 22.7 arcsec/hr.
Position angle of asteroid motion is 108.6 degrees
The recommended exposure time corresponds to 25.0 km per image.
The 1-sigma error in the time of the event is 0.4 seconds.
The 1-sigma cross-track error in the shadow position is 32.8 km.
The sky-plane scale is 3180.3 km/arcsec.
Diameter estimates:
92.9 km assuming a 5% albedo, maximum of 4.6 sec for a central chord
37.9 km assuming a 30% albedo, maximum of 1.9 sec for a central chord
Cross-track diameter of 100.5 km used for deployment plan.
Star training set for 1208_Troilus, (2026/12/04 08:37UT) Object RA Dec mag sep mel Aldebaran 04:37:28.1 +16:33:40 0.8 31.27 129 34Bet Aur 06:01:30.3 +44:56:50 1.9 7.34 110 PPM 047798 05:12:43.5 +46:59:33 6.0 1.39 118 PPM 047921 05:18:31.5 +46:10:05 8.3 0.49 117 PPM 047985 05:21:31.9 +46:39:14 9.7 0.23 116 1208_Troilus 05:20:23.1 +46:32:00 14.1 116 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 26.8 % chance of getting at least one chord. There is a 6.7% 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| RIT | 08:33:54 | -41.5 | Dark | Up | 58.7 | 291.9 | Up | 08:32:13-08:38:13 | 82.2 | 0.120 | Ryan Obs | 08:33:38 | -40.9 | Dark | Up | 56.5 | 296.8 | Up | 08:31:54-08:37:54 | -77.2 | 0.148 | Naylor Obs | 08:33:41 | -41.3 | Dark | Up | 57.0 | 296.3 | Up | 08:30:57-08:36:57 | -91.8 | 0.067 |
This table contains the target star visibility for registered UVa 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 |
|---|---|---|---|---|---|---|---|---|---|---|
Star training set for 1208_Troilus, (2026/12/04 08:37UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 31.27 129 34Bet Aur 05:59:31.6 +44:56:51 1.9 7.34 110 PPM 047798 05:10:43.1 +46:57:40 6.0 1.39 118 PPM 047921 05:16:31.9 +46:08:26 8.3 0.49 117 PPM 047985 05:19:31.5 +46:37:42 9.7 0.23 116 1208_Troilus 05:18:23.0 +46:30:25 14.1 117 Positions are for J2000