Occultation event with (5144) Achates, event index number 1116
Regions able to see the event: US,RECON
Geocentric closest approach at 2025/07/07 10:30:21 UTC
J2000 position of star is 03:09:49.5 +25:59:02
Equinox of date position of star is 03:11:20.3 +26:04:46
Star is 166 degrees from the moon. Moon is 89% illuminated.
Stellar brightness G=12.4, apparent brightess of occulting body is G=15.0
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 16.3 per integration for unocculted signal
Expected flux drop is 92% with SNR of 15.0 for the occulted depth (per occulted point)
Apparent velocity is 29.5 km/sec on the sky relative to the star, or, 25.3 arcsec/hr.
The recommended exposure time corresponds to 3.5 km per image.
The 1-sigma error in the time of the event is 1.1 seconds.
The 1-sigma cross-track error in the shadow position is 18.7 km.
The sky-plane scale is 4200.4 km/arcsec.
Diameter estimates:
87.5 km assuming a 5% albedo, aximum of 3.0 sec for a central chord
35.7 km assuming a 30% albedo, maximum of 1.2 sec for a central chord
Cross-track diameter of 87.5 km used for deployment plan.
Star training set for 5144_Achates, (2025/07/07 10:30UT) Object RA Dec mag sep mel Aldebaran 04:37:23.3 +16:33:30 0.8 22.14 169 44Zet Per 03:55:44.5 +31:57:26 2.8 11.34 173 52 Ari 03:06:56.8 +25:21:10 6.1 1.23 165 PPM 092237 03:10:21.4 +25:27:50 8.2 0.65 165 PPM 092231 03:09:57.8 +26:04:00 8.8 0.31 165 PPM 092260 03:11:49.0 +26:11:21 10.8 0.15 166 5144_Achates 03:11:20.3 +26:04:46 15.0 166 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 1.4 % chance of getting at least one chord. There is a 0.3% 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Idyllwild | 10:28:13 | -22.5 | Dark | Down | 20.7 | 71.9 | Low | 10:26:03-10:32:03 | -78.7 | 0.014 | Laughlin/Bullhead City | 10:28:17 | -20.3 | Dark | Down | 22.9 | 73.5 | Low | 10:26:06-10:32:06 | -89.9 | 0.003 |
Star training set for 5144_Achates, (2025/07/07 10:30UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 22.14 169 44Zet Per 03:54:07.9 +31:53:01 2.8 11.34 173 52 Ari 03:05:26.7 +25:15:19 6.1 1.23 165 PPM 092237 03:08:51.0 +25:22:04 8.2 0.65 165 PPM 092231 03:08:27.1 +25:58:13 8.8 0.31 165 PPM 092260 03:10:18.2 +26:05:37 10.8 0.15 166 5144_Achates 03:09:49.5 +25:59:02 15.0 166 Positions are for J2000