RECON observing guide for 1868_Thersites_20260301123422

Occultation event with (1868) Thersites, event index number 3328
Regions able to see the event: Japan

Geocentric closest approach at 2026/03/01 12:34:22 UTC

J2000 position of star is 10:54:14.1 -04:50:24
Equinox of date position of star is 10:55:33.8 -04:58:47
Star is 33 degrees from the moon. Moon is 95% illuminated.
Stellar brightness G=16.4, apparent brightess of occulting body is G=14.8
Use an exposure time of 1.05 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 19% with SNR of 0.6 for the occulted depth (per occulted point)

Apparent velocity is 18.6 km/sec on the sky relative to the star, or, 19.0 arcsec/hr.
Position angle of asteroid motion is 119.7 degrees
The recommended exposure time corresponds to 19.6 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 31.1 km.
The sky-plane scale is 3521.8 km/arcsec.

Diameter estimates:
76.9 km assuming a 5% albedo, maximum of 4.1 sec for a central chord
31.4 km assuming a 30% albedo, maximum of 1.7 sec for a central chord
Cross-track diameter of 68.2 km used for deployment plan.

Star training set for 1868_Thersites, (2026/03/01 12:34UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:09:45.8 +11:50:18  1.3 20.31  14
PPM 193861     10:52:25.2 -03:13:55  5.8  1.92  31
PPM 193866     10:52:38.1 -04:52:33  7.3  0.74  32
PPM 193910     10:55:06.5 -04:46:15  9.5  0.24  33
1868_Thersites 10:55:33.8 -04:58:47 14.8        33
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 50.3 % 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 12:38:20 -46.0 Dark Up 35.3 136.2 Up 12:35:22-12:41:22 -26.2 0.503

Azimuth is measured in degrees eastward from north. North is at an azimuth of 0, due East is at an azimuth of 90 degrees, due South is 180, and due West is 270.

Star training set for 1868_Thersites, (2026/03/01 12:34UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:08:21.9 +11:58:02  1.3 20.31  14
PPM 193861     10:51:05.3 -03:05:34  5.8  1.92  31
PPM 193866     10:51:18.5 -04:44:12  7.3  0.74  32
PPM 193910     10:53:46.9 -04:37:52  9.5  0.24  33
1868_Thersites 10:54:14.1 -04:50:24 14.8        33
Positions are for J2000


Created by recondetail.pro, 2025/06/18 23:09:11 MT