Occultation event with (588) Achilles, event index number 3728
Regions able to see the event: SAmericaS
Geocentric closest approach at 2026/05/08 22:48:22 UTC
J2000 position of star is 12:24:19.9 -14:22:07
Equinox of date position of star is 12:25:42.0 -14:30:52
Star is 115 degrees from the moon. Moon is 59% illuminated.
Stellar brightness G=15.9, apparent brightess of occulting body is G=13.5
Use an exposure time of 2.00 seconds with the standard RECON-QHY system.
SNR of 4.9 per integration for unocculted signal
Expected flux drop is 9% with SNR of 0.5 for the occulted depth (per occulted point)
Apparent velocity is 11.4 km/sec on the sky relative to the star, or, 12.6 arcsec/hr.
Position angle of asteroid motion is 123.5 degrees
The recommended exposure time corresponds to 22.8 km per image.
The 1-sigma error in the time of the event is 3.0 seconds.
The 1-sigma cross-track error in the shadow position is 17.3 km.
The sky-plane scale is 3268.6 km/arcsec.
Diameter estimates:
136.1 km assuming a 5% albedo, maximum of 11.9 sec for a central chord
55.6 km assuming a 30% albedo, maximum of 4.9 sec for a central chord
Cross-track diameter of 130.1 km used for deployment plan.
Star training set for 588_Achilles, (2026/05/08 22:48UT) Object RA Dec mag sep mel Spica 13:26:35.1 -11:17:53 1.0 15.18 104 4Gam Crv 12:17:09.9 -17:41:17 2.6 3.78 115 PPM 225705 12:22:17.5 -13:42:42 5.1 1.15 117 PPM 225827 12:27:21.6 -15:05:37 7.1 0.70 115 PPM 225786 12:25:44.1 -14:35:51 9.4 0.08 115 588_Achilles 12:25:42.0 -14:30:52 13.5 115 Positions are for equinox of date
This table contains the target star visibility for registered SAmericaS 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 588_Achilles, (2026/05/08 22:48UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 15.18 104 4Gam Crv 12:15:48.1 -17:32:30 2.6 3.78 115 PPM 225705 12:20:55.7 -13:33:56 5.1 1.15 117 PPM 225827 12:25:59.4 -14:56:53 7.1 0.70 115 PPM 225786 12:24:22.1 -14:27:06 9.4 0.08 115 588_Achilles 12:24:19.9 -14:22:07 13.5 115 Positions are for J2000