Occultation event with (3540) Protesilaos, event index number 3097
Regions able to see the event: US,UVa
Geocentric closest approach at 2026/01/02 07:59:58 UTC
J2000 position of star is 12:55:22.3 +07:08:23
Equinox of date position of star is 12:56:41.2 +06:59:57
Star is 102 degrees from the moon. Moon is 98% illuminated.
Stellar brightness G=15.0, apparent brightess of occulting body is G=14.6
Use an exposure time of 1.05 seconds with the standard RECON-QHY system.
SNR of 9.8 per integration for unocculted signal
Expected flux drop is 41% with SNR of 4.0 for the occulted depth (per occulted point)
Apparent velocity is 11.9 km/sec on the sky relative to the star, or, 12.8 arcsec/hr.
Position angle of asteroid motion is 109.7 degrees
The recommended exposure time corresponds to 12.5 km per image.
The 1-sigma error in the time of the event is 3.1 seconds.
The 1-sigma cross-track error in the shadow position is 16.8 km.
The sky-plane scale is 3340.8 km/arcsec.
Diameter estimates:
80.5 km assuming a 5% albedo, maximum of 6.8 sec for a central chord
32.9 km assuming a 30% albedo, maximum of 2.8 sec for a central chord
Cross-track diameter of 70.2 km used for deployment plan.
Star training set for 3540_Protesilaos, (2026/01/02 08:00UT) Object RA Dec mag sep mel Spica 13:26:34.0 -11:17:46 1.0 19.75 117 Vindemiatrix 13:03:28.3 +10:49:12 2.8 4.17 101 32 Vir 12:46:55.9 +07:31:53 5.2 2.48 99 PPM 159338 12:58:32.2 +08:09:13 7.2 1.24 102 PPM 159331 12:57:59.3 +06:52:46 10.0 0.34 102 PPM 159308 12:56:32.2 +06:57:28 10.1 0.06 102 3540_Protesila 12:56:41.2 +06:59:57 14.6 102 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| NSmith | 07:52:27 | -60.0 | Dark | Up | 29.2 | 102.5 | Up | 07:50:16-07:56:16 | 97.6 | 0.000 | Cobble | 07:51:46 | -69.3 | Dark | Up | 20.3 | 94.8 | Up | 07:50:13-07:56:13 | -127.7 | 0.000 | Hodapp | 07:51:48 | -68.9 | Dark | Up | 20.7 | 95.0 | Up | 07:50:15-07:56:15 | -129.2 | 0.000 |
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 3540_Protesilaos, (2026/01/02 08:00UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 19.75 117 Vindemiatrix 13:02:10.1 +10:57:33 2.8 4.17 101 32 Vir 12:45:36.9 +07:40:24 5.2 2.48 99 PPM 159338 12:57:13.4 +08:17:38 7.2 1.24 102 PPM 159331 12:56:40.3 +07:01:11 10.0 0.34 102 PPM 159308 12:55:13.3 +07:05:53 10.1 0.06 102 3540_Protesila 12:55:22.3 +07:08:23 14.6 102 Positions are for J2000