RECON observing guide for 4138_Kalchas_20250516165809

Occultation event with (4138) Kalchas, event index number 977
Regions able to see the event: SAfrica

Geocentric closest approach at 2025/05/16 16:58:09 UTC

J2000 position of star is 09:55:13.8 +10:54:28
Equinox of date position of star is 09:56:35.2 +10:47:12
Star is 133 degrees from the moon. Moon is 85% illuminated.
Stellar brightness G=16.1, apparent brightess of occulting body is G=15.9
Use an exposure time of 1.20 seconds with the standard RECON-QHY system.
SNR of 4.8 per integration for unocculted signal
Expected flux drop is 45% with SNR of 2.2 for the occulted depth (per occulted point)

Apparent velocity is 11.4 km/sec on the sky relative to the star, or, 10.8 arcsec/hr.
The recommended exposure time corresponds to 13.7 km per image.
The 1-sigma error in the time of the event is 4.3 seconds.
The 1-sigma cross-track error in the shadow position is 28.6 km.
The sky-plane scale is 3794.2 km/arcsec.

Diameter estimates:
55.7 km assuming a 5% albedo, aximum of 4.9 sec for a central chord
22.8 km assuming a 30% albedo, maximum of 2.0 sec for a central chord
Cross-track diameter of 55.7 km used for deployment plan.

Star training set for 4138_Kalchas, (2025/05/16 16:58UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:09:43.2 +11:50:32  1.3  3.39 131
PPM 126849     09:52:11.0 +11:43:21  6.5  1.43 135
PPM 126943     09:57:43.5 +10:32:38  8.0  0.37 133
PPM 126939     09:57:27.8 +10:39:58  9.6  0.25 133
PPM 126918     09:56:06.2 +10:58:59 10.1  0.23 133
4138_Kalchas   09:56:35.2 +10:47:12 15.9       133
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 4138_Kalchas, (2025/05/16 16:58UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:08:21.9 +11:58:02  1.3  3.39 131
PPM 126849     09:50:49.2 +11:50:32  6.5  1.43 135
PPM 126943     09:56:22.3 +10:39:55  8.0  0.37 133
PPM 126939     09:56:06.5 +10:47:15  9.6  0.25 133
PPM 126918     09:54:44.7 +11:06:14 10.1  0.23 133
4138_Kalchas   09:55:13.8 +10:54:28 15.9       133
Positions are for J2000


Created by recondetail.pro, 2025/03/14 11:24:15 MT