RECON observing guide for 1868_Thersites_20250521194553

Occultation event with (1868) Thersites, event index number 991
Regions able to see the event: Europe

Geocentric closest approach at 2025/05/21 19:45:53 UTC

J2000 position of star is 08:59:47.3 +03:39:14
Equinox of date position of star is 09:01:06.9 +03:33:14
Star is 146 degrees from the moon. Moon is 36% illuminated.
Stellar brightness G=16.9, apparent brightess of occulting body is G=15.6
Use an exposure time of 1.75 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 23% with SNR of 0.7 for the occulted depth (per occulted point)

Apparent velocity is 20.5 km/sec on the sky relative to the star, or, 17.3 arcsec/hr.
The recommended exposure time corresponds to 35.8 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 12.1 km.
The sky-plane scale is 4248.1 km/arcsec.

Diameter estimates:
76.2 km assuming a 5% albedo, aximum of 3.7 sec for a central chord
31.1 km assuming a 30% albedo, maximum of 1.5 sec for a central chord
Cross-track diameter of 76.2 km used for deployment plan.

Star training set for 1868_Thersites, (2025/05/21 19:46UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:09:43.3 +11:50:32  1.3 18.90 162
Alphard        09:28:50.1 -08:46:12  2.0 14.13 149
18Ome Hya      09:07:18.5 +04:59:22  5.0  2.11 148
PPM 155269     09:00:18.9 +03:33:23  8.4  0.20 146
PPM 155283     09:00:55.9 +03:32:04  9.6  0.05 146
1868_Thersites 09:01:06.9 +03:33:14 15.6       146
Positions are for equinox of date

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, (2025/05/21 19:46UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:08:21.9 +11:58:02  1.3 18.90 162
Alphard        09:27:35.2 -08:39:30  2.0 14.13 149
18Ome Hya      09:05:58.3 +05:05:32  5.0  2.11 148
PPM 155269     08:58:59.3 +03:39:22  8.4  0.20 146
PPM 155283     08:59:36.3 +03:38:04  9.6  0.05 146
1868_Thersites 08:59:47.3 +03:39:14 15.6       146
Positions are for J2000


Created by recondetail.pro, 2025/03/15 08:40:00 MT