Occultation event with (4035) Thestor, event index number 839
Regions able to see the event: US
Geocentric closest approach at 2025/03/21 01:59:50 UTC
J2000 position of star is 08:32:05.3 +04:29:31
Equinox of date position of star is 08:33:24.9 +04:24:19
Star is 123 degrees from the moon. Moon is 64% illuminated.
Stellar brightness G=15.2, apparent brightess of occulting body is G=14.8
Use an exposure time of 1.50 seconds with the standard RECON-QHY system.
Expected flux drop is 60% with SNR of 10.0 per integration
Apparent velocity is 7.6 km/sec on the sky relative to the star, or, 8.5 arcsec/hr.
The recommended exposure time corresponds to 11.4 km per image.
The 1-sigma error in the time of the event is 2.8 seconds.
The 1-sigma cross-track error in the shadow position is 39.5 km.
The sky-plane scale is 3239.6 km/arcsec.
Diameter estimates:
73.1 km assuming a 5% albedo, aximum of 9.6 sec for a central chord
29.9 km assuming a 30% albedo, maximum of 3.9 sec for a central chord
Cross-track diameter of 73.1 km used for deployment plan.
Star training set for 4035_Thestor, (2025/03/21 02:00UT) Object RA Dec mag sep mel Regulus 10:09:42.7 +11:50:35 1.3 24.95 105 Alphard 09:28:49.6 -08:46:09 2.0 19.09 104 4Del Hya 08:38:59.4 +05:36:51 4.2 1.84 122 PPM 154652 08:35:03.2 +04:40:09 7.9 0.49 123 PPM 154635 08:34:16.5 +04:33:37 10.0 0.26 123 PPM 154614 08:33:28.1 +04:32:13 10.8 0.13 123 4035_Thestor 08:33:24.9 +04:24:19 14.8 122 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 |
|---|---|---|---|---|---|---|---|---|---|---|
Star training set for 4035_Thestor, (2025/03/21 02:00UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 24.95 105 Alphard 09:27:35.2 -08:39:30 2.0 19.09 104 4Del Hya 08:37:39.3 +05:42:13 4.2 1.84 122 PPM 154652 08:33:43.4 +04:45:24 7.9 0.49 123 PPM 154635 08:32:56.8 +04:38:51 10.0 0.26 123 PPM 154614 08:32:08.4 +04:37:25 10.8 0.13 123 4035_Thestor 08:32:05.3 +04:29:31 14.8 123 Positions are for J2000