Occultation event with (17172) 99NZ41, event index number 3222
Regions able to see the event: Japan
Geocentric closest approach at 2026/02/07 12:55:29 UTC
J2000 position of star is 03:48:40.7 -09:23:09
Equinox of date position of star is 03:49:56.2 -09:18:26
Star is 139 degrees from the moon. Moon is 69% illuminated.
Stellar brightness G=12.5, apparent brightess of occulting body is G=16.4
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 15.2 per integration for unocculted signal
Expected flux drop is 97% with SNR of 14.8 for the occulted depth (per occulted point)
Apparent velocity is 18.6 km/sec on the sky relative to the star, or, 18.7 arcsec/hr.
Position angle of asteroid motion is 20.9 degrees
The recommended exposure time corresponds to 2.2 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 2.6 km.
The sky-plane scale is 3593.5 km/arcsec.
Diameter estimates:
40.9 km assuming a 5% albedo, maximum of 2.2 sec for a central chord
16.7 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 34.5 km used for deployment plan.
Star training set for 17172_99NZ41, (2026/02/07 12:55UT) Object RA Dec mag sep mel Rigel 05:15:47.6 -08:10:24 0.1 21.24 121 Menkar 03:03:38.8 +04:11:26 2.5 17.75 156 23Del Eri 03:44:30.1 -09:40:36 3.5 1.39 140 PPM 186173 03:47:52.0 -09:21:46 8.5 0.51 140 PPM 186222 03:50:51.6 -09:23:09 9.5 0.24 139 17172_99NZ41 03:49:56.2 -09:18:26 16.4 139 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 | 13:00:16 | -57.1 | Dark | Down | 21.2 | 240.4 | Really Low | 12:57:28-13:03:28 | 61.5 | 0.000 |
Star training set for 17172_99NZ41, (2026/02/07 12:55UT) Object RA Dec mag sep mel Rigel 05:14:32.3 -08:12:06 0.1 21.24 121 Menkar 03:02:16.8 +04:05:21 2.5 17.75 156 23Del Eri 03:43:14.7 -09:45:29 3.5 1.39 140 PPM 186173 03:46:36.6 -09:26:33 8.5 0.51 140 PPM 186222 03:49:36.3 -09:27:49 9.5 0.24 139 17172_99NZ41 03:48:40.7 -09:23:09 16.4 139 Positions are for J2000