Occultation event with (3564) Talthybius, event index number 3476
Regions able to see the event: US,RECON,SwRI-CO,UVa
Geocentric closest approach at 2026/03/21 04:33:24 UTC
J2000 position of star is 10:43:36.3 +22:37:14
Equinox of date position of star is 10:45:01.6 +22:28:57
Star is 123 degrees from the moon. Moon is 6% illuminated.
Stellar brightness G=12.2, apparent brightess of occulting body is G=14.4
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 18.4 per integration for unocculted signal
Expected flux drop is 88% with SNR of 16.2 for the occulted depth (per occulted point)
Apparent velocity is 15.0 km/sec on the sky relative to the star, or, 17.6 arcsec/hr.
Position angle of asteroid motion is 92.3 degrees
The recommended exposure time corresponds to 1.8 km per image.
The 1-sigma error in the time of the event is 1.4 seconds.
The 1-sigma cross-track error in the shadow position is 30.5 km.
The sky-plane scale is 3058.9 km/arcsec.
Diameter estimates:
77.6 km assuming a 5% albedo, maximum of 5.2 sec for a central chord
31.7 km assuming a 30% albedo, maximum of 2.1 sec for a central chord
Cross-track diameter of 73.7 km used for deployment plan.
Star training set for 3564_Talthybius, (2026/03/21 04:33UT) Object RA Dec mag sep mel Regulus 10:09:45.9 +11:50:17 1.3 13.56 121 68Del Leo 11:15:29.9 +20:22:47 2.6 7.40 130 41 LMi 10:44:50.2 +23:03:02 5.1 0.57 122 PPM 100639 10:48:42.0 +22:26:12 7.7 0.85 123 41 LMi 10:44:50.2 +23:03:02 5.1 0.57 122 PPM 100605 10:45:40.2 +22:32:15 11.1 0.16 123 3564_Talthybiu 10:45:01.6 +22:28:57 14.4 123 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Ryan Obs | 04:32:36 | -48.9 | Dark | Down | 70.9 | 208.3 | Up | 04:31:32-04:37:32 | 226.8 | 0.000 |
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 15.6 % 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Hawthorne | 04:36:27 | -29.1 | Dark | Down | 58.6 | 111.2 | Up | 04:33:03-04:39:03 | 213.1 | 0.000 | Lee Vining | 04:36:30 | -29.0 | Dark | Down | 58.5 | 109.8 | Up | 04:33:05-04:39:05 | 161.5 | 0.000 | Bishop | 04:36:29 | -29.6 | Dark | Down | 59.0 | 109.6 | Up | 04:33:04-04:39:04 | 104.0 | 0.009 | North Las Vegas | 04:36:14 | -32.4 | Dark | Down | 61.9 | 111.3 | Up | 04:33:05-04:39:05 | -63.4 | 0.147 | Laughlin/Bullhead City | 04:36:12 | -33.5 | Dark | Down | 62.8 | 110.0 | Up | 04:33:22-04:39:22 | -196.6 | 0.000 | Kingman/Dolan Springs | 04:36:10 | -33.8 | Dark | Down | 63.2 | 110.6 | Up | 04:33:04-04:39:04 | -200.7 | 0.000 |
This table contains the target star visibility for registered SwRI-CO 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| CU-SBO | 04:35:16 | -36.8 | Dark | Down | 66.5 | 132.2 | Up | 04:32:17-04:38:17 | 223.9 | 0.000 | Nederland | 04:35:17 | -36.7 | Dark | Down | 66.4 | 131.9 | Up | 04:32:15-04:38:15 | 223.7 | 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 99.8 % chance of getting at least one chord. There is a 86.4% 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Culpeper | 04:32:44 | -49.9 | Dark | Down | 72.7 | 205.6 | Up | 04:29:47-04:35:47 | 67.4 | 0.121 | Green_Bank | 04:32:55 | -49.4 | Dark | Down | 73.3 | 200.4 | Up | 04:29:48-04:35:48 | 50.0 | 0.271 | Crozet | 04:32:48 | -50.1 | Dark | Down | 73.3 | 204.3 | Up | 04:29:43-04:35:43 | 20.9 | 0.591 | Lake_Anna | 04:32:43 | -50.3 | Dark | Down | 73.1 | 206.6 | Up | 04:29:44-04:35:44 | 19.6 | 0.604 | Charlottesville | 04:32:47 | -50.2 | Dark | Down | 73.3 | 204.9 | Up | 04:29:50-04:35:50 | 17.2 | 0.624 | Richmond | 04:32:40 | -50.9 | Dark | Down | 73.3 | 208.7 | Up | 04:29:55-04:35:55 | -24.3 | 0.564 | Lynchburg | 04:32:50 | -50.6 | Dark | Down | 74.1 | 203.8 | Up | 04:29:40-04:35:40 | -55.6 | 0.222 |
Star training set for 3564_Talthybius, (2026/03/21 04:33UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 13.56 121 68Del Leo 11:14:06.8 +20:31:22 2.6 7.40 130 41 LMi 10:43:24.7 +23:11:18 5.1 0.57 122 PPM 100639 10:47:16.9 +22:34:32 7.7 0.85 123 41 LMi 10:43:24.7 +23:11:18 5.1 0.57 122 PPM 100605 10:44:14.9 +22:40:32 11.1 0.16 123 3564_Talthybiu 10:43:36.3 +22:37:14 14.4 123 Positions are for J2000