Occultation event with (15440) Eioneus, event index number 22
Regions able to see the event: US,RECON,SAmericaN
Geocentric closest approach at 2025/02/22 04:58:58 UTC
J2000 position of star is 08:21:31.3 +24:13:38
Equinox of date position of star is 08:23:00.9 +24:08:44
Star is 139 degrees from the moon. Moon is 36% illuminated.
Stellar brightness G=15.8, apparent brightess of occulting body is G=14.7
Use an exposure time of 1.15 seconds with the standard RECON-QHY system.
Expected flux drop is 72% with SNR of 5.4 per integration
Apparent velocity is 15.4 km/sec on the sky relative to the star, or, 17.3 arcsec/hr.
The recommended exposure time corresponds to 17.7 km per image.
The 1-sigma error in the time of the event is 2.7 seconds.
The 1-sigma cross-track error in the shadow position is 29.4 km.
The sky-plane scale is 3194.5 km/arcsec.
Diameter estimates:
71.4 km assuming a 5% albedo, aximum of 4.6 sec for a central chord
29.2 km assuming a 30% albedo, maximum of 1.9 sec for a central chord
Cross-track diameter of 71.4 km used for deployment plan.
Star training set for 15440_Eioneus, (2025/02/22 04:59UT) Object RA Dec mag sep mel Pollux 07:46:51.1 +27:57:48 1.1 8.97 147 19Lam Cnc 08:22:01.6 +23:56:29 5.9 0.30 139 PPM 098600 08:21:30.1 +23:43:43 7.9 0.54 139 PPM 098633 08:23:26.9 +23:56:31 8.9 0.23 138 PPM 098629 08:23:09.8 +24:08:57 10.5 0.03 139 15440_Eioneus 08:23:00.9 +24:08:44 14.7 138 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 60.9 % 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| George/Scottsdale | 05:00:27 | -46.4 | Dark | Down | 77.3 | 135.5 | Up | 04:55:09-05:01:09 | 18.7 | 0.609 |
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 90.1 % chance of getting at least one chord. There is a 13.0% 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Swift | 05:01:30 | -37.3 | Dark | Down | 68.2 | 125.3 | Up | 04:58:44-05:04:44 | 125.1 | 0.001 | Bishop | 05:01:10 | -40.2 | Dark | Down | 71.0 | 129.1 | Up | 04:58:43-05:04:43 | 122.9 | 0.001 | Kingman/Dolan Springs | 05:00:43 | -44.2 | Dark | Down | 75.0 | 133.6 | Up | 04:58:44-05:04:44 | 72.5 | 0.078 | Laughlin/Bullhead City | 05:00:45 | -43.8 | Dark | Down | 74.7 | 132.2 | Up | 04:58:42-05:04:42 | 49.3 | 0.261 | Lake Havasu City | 05:00:42 | -44.2 | Dark | Down | 75.3 | 130.9 | Up | 04:58:58-05:04:58 | -7.2 | 0.691 |
Star training set for 15440_Eioneus, (2025/02/22 04:59UT) Object RA Dec mag sep mel Pollux 07:45:17.8 +28:01:33 1.1 8.97 147 19Lam Cnc 08:20:32.1 +24:01:20 5.9 0.30 139 PPM 098600 08:20:00.7 +23:48:33 7.9 0.54 139 PPM 098633 08:21:57.4 +24:01:25 8.9 0.23 138 PPM 098629 08:21:40.2 +24:13:50 10.5 0.03 139 15440_Eioneus 08:21:31.3 +24:13:38 14.7 139 Positions are for J2000