Occultation event with (15502) 99NV27, event index number 1229
Regions able to see the event: Japan
Geocentric closest approach at 2025/08/14 13:34:13 UTC
J2000 position of star is 01:47:07.2 +29:55:08
Equinox of date position of star is 01:48:34.9 +30:02:45
Star is 15 degrees from the moon. Moon is 69% illuminated.
Stellar brightness G=16.3, apparent brightess of occulting body is G=15.5
Use an exposure time of 1.35 seconds with the standard RECON-QHY system.
SNR of 4.1 per integration for unocculted signal
Expected flux drop is 32% with SNR of 1.3 for the occulted depth (per occulted point)
Apparent velocity is 9.8 km/sec on the sky relative to the star, or, 10.2 arcsec/hr.
Position angle of asteroid motion is 5.9 degrees
The recommended exposure time corresponds to 13.2 km per image.
The 1-sigma error in the time of the event is 2.5 seconds.
The 1-sigma cross-track error in the shadow position is 7.4 km.
The sky-plane scale is 3462.6 km/arcsec.
Diameter estimates:
57.5 km assuming a 5% albedo, aximum of 5.9 sec for a central chord
23.5 km assuming a 30% albedo, maximum of 2.4 sec for a central chord
Cross-track diameter of 53.1 km used for deployment plan.
Star training set for 15502_99NV27, (2025/08/14 13:34UT) Object RA Dec mag sep mel Aldebaran 04:37:23.6 +16:33:31 0.8 40.77 41 Hamal 02:08:37.4 +23:34:56 2.0 7.86 10 2Alp Tri 01:54:33.0 +29:42:09 3.4 1.34 15 PPM 066663 01:51:52.2 +30:55:46 8.4 1.13 16 PPM 066605 01:48:06.8 +30:19:17 9.2 0.29 15 15502_99NV27 01:48:34.9 +30:02:45 15.5 15 Positions are for equinox of date
This table contains the target star visibility for registered Japan 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Akita | 13:37:57 | -33.9 | Dark | Up | 26.5 | 71.9 | Really Low | 13:34:38-13:40:38 | 46.6 | 0.000 |
Star training set for 15502_99NV27, (2025/08/14 13:34UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 40.77 41 Hamal 02:07:10.8 +23:27:41 2.0 7.86 10 2Alp Tri 01:53:04.9 +29:34:38 3.4 1.34 15 PPM 066663 01:50:23.9 +30:48:12 8.4 1.13 16 PPM 066605 01:46:39.1 +30:11:39 9.2 0.29 15 15502_99NV27 01:47:07.2 +29:55:08 15.5 15 Positions are for J2000