Occultation event with (21595) 98WJ5, event index number 3440
Regions able to see the event: Japan
Geocentric closest approach at 2026/03/15 18:05:28 UTC
J2000 position of star is 12:44:40.4 +16:15:04
Equinox of date position of star is 12:45:59.0 +16:06:29
Star is 129 degrees from the moon. Moon is 12% illuminated.
Stellar brightness G=14.9, apparent brightess of occulting body is G=16.1
Use an exposure time of 0.45 seconds with the standard RECON-QHY system.
SNR of 6.9 per integration for unocculted signal
Expected flux drop is 76% with SNR of 5.2 for the occulted depth (per occulted point)
Apparent velocity is 19.2 km/sec on the sky relative to the star, or, 19.9 arcsec/hr.
Position angle of asteroid motion is 130.8 degrees
The recommended exposure time corresponds to 8.6 km per image.
The 1-sigma error in the time of the event is 1.3 seconds.
The 1-sigma cross-track error in the shadow position is 25.0 km.
The sky-plane scale is 3472.2 km/arcsec.
Diameter estimates:
42.1 km assuming a 5% albedo, maximum of 2.2 sec for a central chord
17.2 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 35.2 km used for deployment plan.
Star training set for 21595_98WJ5, (2026/03/15 18:05UT) Object RA Dec mag sep mel Arcturus 14:16:51.5 +19:02:51 0.0 21.84 108 Vindemiatrix 13:03:28.9 +10:49:08 2.8 6.79 123 PPM 129407 12:53:45.6 +15:58:49 6.3 1.87 127 PPM 129330 12:48:29.2 +15:26:55 7.3 0.89 128 PPM 129269 12:44:22.4 +16:05:27 10.0 0.39 129 PPM 129289 12:46:07.8 +16:10:42 11.2 0.08 129 21595_98WJ5 12:45:59.0 +16:06:29 16.1 128 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| Tokyo | 18:04:49 | -33.8 | Dark | Down | 54.8 | 245.2 | Up | 18:02:05-18:08:05 | 146.9 | 0.000 |
Star training set for 21595_98WJ5, (2026/03/15 18:05UT) Object RA Dec mag sep mel Arcturus 14:15:37.7 +19:10:06 0.0 21.84 108 Vindemiatrix 13:02:10.1 +10:57:33 2.8 6.79 123 PPM 129407 12:52:27.3 +16:07:20 6.3 1.87 127 PPM 129330 12:47:10.6 +15:35:29 7.3 0.89 128 PPM 129269 12:43:03.8 +16:14:02 10.0 0.39 129 PPM 129289 12:44:49.3 +16:19:17 11.2 0.08 129 21595_98WJ5 12:44:40.4 +16:15:04 16.1 129 Positions are for J2000