Occultation event with (24313) 99YR27, event index number 908
Regions able to see the event: US,RECON
Geocentric closest approach at 2025/04/16 06:25:09 UTC
J2000 position of star is 09:28:27.1 +34:19:21
Equinox of date position of star is 09:29:58.9 +34:12:40
Star is 109 degrees from the moon. Moon is 91% illuminated.
Stellar brightness G=15.4, apparent brightess of occulting body is G=16.4
Use an exposure time of 1.00 seconds with the standard RECON-QHY system.
SNR of 7.9 per integration for unocculted signal
Expected flux drop is 72% with SNR of 5.7 for the occulted depth (per occulted point)
Apparent velocity is 10.1 km/sec on the sky relative to the star, or, 10.0 arcsec/hr.
The recommended exposure time corresponds to 10.1 km per image.
The 1-sigma error in the time of the event is 2.3 seconds.
The 1-sigma cross-track error in the shadow position is 53.3 km.
The sky-plane scale is 3646.0 km/arcsec.
Diameter estimates:
41.5 km assuming a 5% albedo, aximum of 4.1 sec for a central chord
16.9 km assuming a 30% albedo, maximum of 1.7 sec for a central chord
Cross-track diameter of 41.5 km used for deployment plan.
Star training set for 24313_99YR27, (2025/04/16 06:25UT) Object RA Dec mag sep mel Pollux 07:46:51.6 +27:57:47 1.1 22.87 129 40Alp Lyn 09:22:35.3 +34:17:03 3.1 1.53 110 PPM 074460 09:25:22.9 +34:26:17 8.1 0.98 110 PPM 074521 09:29:03.9 +34:35:32 10.0 0.43 109 PPM 074537 09:30:38.9 +33:54:16 10.4 0.34 109 24313_99YR27 09:29:58.9 +34:12:40 16.4 109 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 36.3 % chance of getting at least one chord. There is a 2.5% 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Wildwood | 06:24:05 | -40.8 | Dark | Up | 57.2 | 281.9 | Up | 06:18:42-06:24:42 | 134.6 | 0.012 | Idyllwild | 06:24:02 | -41.9 | Dark | Up | 55.6 | 283.0 | Up | 06:18:57-06:24:57 | -12.3 | 0.260 | Laughlin/Bullhead City | 06:23:40 | -41.3 | Dark | Up | 54.2 | 281.7 | Up | 06:18:36-06:24:36 | -89.0 | 0.069 | Calipatria | 06:24:03 | -42.9 | Dark | Up | 54.5 | 284.2 | Up | 06:18:29-06:24:29 | -118.9 | 0.024 | Kingman/Dolan Springs | 06:23:38 | -41.5 | Dark | Up | 53.8 | 281.8 | Up | 06:17:36-06:23:36 | -122.1 | 0.021 | Lake Havasu City | 06:23:46 | -42.0 | Dark | Up | 53.9 | 282.7 | Up | 06:20:31-06:26:31 | -137.1 | 0.011 | Yuma | 06:24:04 | -43.6 | Dark | Up | 53.6 | 285.0 | Up | 06:19:03-06:25:03 | -198.3 | 0.000 |
Star training set for 24313_99YR27, (2025/04/16 06:25UT) Object RA Dec mag sep mel Pollux 07:45:17.8 +28:01:33 1.1 22.87 129 40Alp Lyn 09:21:02.9 +34:23:34 3.1 1.53 110 PPM 074460 09:23:50.5 +34:32:52 8.1 0.98 110 PPM 074521 09:27:31.8 +34:42:12 10.0 0.43 109 PPM 074537 09:29:07.3 +34:00:58 10.4 0.34 109 24313_99YR27 09:28:27.1 +34:19:21 16.4 109 Positions are for J2000