Occultation event with (17171) 99NB38, event index number 5127
Regions able to see the event: US,Europe,SwRI-CO,NMexico
Geocentric closest approach at 2026/12/09 03:46:51 UTC
J2000 position of star is 06:01:58.3 +47:35:57
Equinox of date position of star is 06:04:00.5 +47:35:50
Star is 157 degrees from the moon. Moon is 0% illuminated.
Stellar brightness G=16.4, apparent brightess of occulting body is G=15.7
Use an exposure time of 0.90 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 35% with SNR of 1.1 for the occulted depth (per occulted point)
Apparent velocity is 17.5 km/sec on the sky relative to the star, or, 19.4 arcsec/hr.
Position angle of asteroid motion is 87.4 degrees
The recommended exposure time corresponds to 15.8 km per image.
The 1-sigma error in the time of the event is 0.4 seconds.
The 1-sigma cross-track error in the shadow position is 28.4 km.
The sky-plane scale is 3257.7 km/arcsec.
Diameter estimates:
46.1 km assuming a 5% albedo, maximum of 2.6 sec for a central chord
18.8 km assuming a 30% albedo, maximum of 1.1 sec for a central chord
Cross-track diameter of 40.9 km used for deployment plan.
Star training set for 17171_99NB38, (2026/12/09 03:47UT) Object RA Dec mag sep mel Pollux 07:46:57.7 +27:57:32 1.1 28.03 145 34Bet Aur 06:01:30.3 +44:56:50 1.9 2.69 160 36 Aur 06:03:01.1 +47:54:01 5.7 0.35 157 PPM 048679 06:04:47.7 +47:48:28 6.9 0.25 157 PPM 048664 06:03:42.1 +47:32:28 11.3 0.08 157 17171_99NB38 06:04:00.5 +47:35:50 15.7 157 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 51.6 % chance of getting at least one chord. There is a 5.5% 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| RIT | 03:49:28 | -64.7 | Dark | Down | 66.6 | 67.4 | Up | 03:46:50-03:52:50 | -15.7 | 0.406 | Getrost | 03:49:50 | -63.6 | Dark | Down | 62.9 | 63.5 | Up | 03:48:02-03:54:02 | -44.2 | 0.161 | Cobble | 03:51:02 | -56.1 | Dark | Down | 49.2 | 53.6 | Up | 03:46:28-03:52:28 | -94.3 | 0.003 | Hodapp | 03:51:00 | -56.5 | Dark | Down | 49.5 | 53.6 | Up | 03:47:19-03:53:19 | -122.0 | 0.000 |
This table contains the target star visibility for registered SwRI-CO 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 |
|---|---|---|---|---|---|---|---|---|---|---|
Star training set for 17171_99NB38, (2026/12/09 03:47UT) Object RA Dec mag sep mel Pollux 07:45:17.7 +28:01:33 1.1 28.03 145 34Bet Aur 05:59:31.6 +44:56:51 1.9 2.69 160 36 Aur 06:00:58.5 +47:54:06 5.7 0.35 157 PPM 048679 06:02:45.2 +47:48:37 6.9 0.25 157 PPM 048664 06:01:39.9 +47:32:34 11.3 0.08 157 17171_99NB38 06:01:58.3 +47:35:57 15.7 157 Positions are for J2000