Occultation event with (16974) Iphthime, event index number 986
Regions able to see the event: SAfrica
Geocentric closest approach at 2025/05/18 17:16:15 UTC
J2000 position of star is 08:43:32.6 +03:11:27
Equinox of date position of star is 08:44:52.1 +03:05:53
Star is 161 degrees from the moon. Moon is 69% illuminated.
Stellar brightness G=15.4, apparent brightess of occulting body is G=15.8
Use an exposure time of 0.70 seconds with the standard RECON-QHY system.
SNR of 5.9 per integration for unocculted signal
Expected flux drop is 58% with SNR of 3.4 for the occulted depth (per occulted point)
Apparent velocity is 20.8 km/sec on the sky relative to the star, or, 18.6 arcsec/hr.
Position angle of asteroid motion is 355.4 degrees
The recommended exposure time corresponds to 14.5 km per image.
The 1-sigma error in the time of the event is 2.0 seconds.
The 1-sigma cross-track error in the shadow position is 15.7 km.
The sky-plane scale is 4012.0 km/arcsec.
Diameter estimates:
62.0 km assuming a 5% albedo, aximum of 3.0 sec for a central chord
25.3 km assuming a 30% albedo, maximum of 1.2 sec for a central chord
Cross-track diameter of 62.0 km used for deployment plan.
Star training set for 16974_Iphthime, (2025/05/18 17:16UT) Object RA Dec mag sep mel Regulus 10:09:43.3 +11:50:32 1.3 22.76 156 Alphard 09:28:50.1 -08:46:11 2.0 16.15 147 7Eta Hya 08:44:33.1 +03:18:20 4.0 0.22 161 PPM 154936 08:46:32.1 +04:08:07 8.5 1.12 162 PPM 154918 08:45:29.3 +02:58:12 8.9 0.20 161 16974_Iphthime 08:44:52.1 +03:05:53 15.8 161 Positions are for equinox of date
Star training set for 16974_Iphthime, (2025/05/18 17:16UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 22.76 156 Alphard 09:27:35.2 -08:39:30 2.0 16.15 147 7Eta Hya 08:43:13.6 +03:23:53 4.0 0.22 161 PPM 154936 08:45:12.2 +04:13:43 8.5 1.12 162 PPM 154918 08:44:09.9 +03:03:47 8.9 0.20 161 16974_Iphthime 08:43:32.6 +03:11:27 15.8 161 Positions are for J2000