Occultation event with (4489) Dracius, event index number 924
Regions able to see the event: US
Geocentric closest approach at 2025/04/22 07:39:53 UTC
J2000 position of star is 07:48:49.7 +35:22:21
Equinox of date position of star is 07:50:28.8 +35:18:27
Star is 153 degrees from the moon. Moon is 37% illuminated.
Stellar brightness G=15.3, apparent brightess of occulting body is G=14.5
Use an exposure time of 1.30 seconds with the standard RECON-QHY system.
SNR of 8.5 per integration for unocculted signal
Expected flux drop is 33% with SNR of 2.8 for the occulted depth (per occulted point)
Apparent velocity is 17.3 km/sec on the sky relative to the star, or, 17.3 arcsec/hr.
The recommended exposure time corresponds to 22.5 km per image.
The 1-sigma error in the time of the event is 2.2 seconds.
The 1-sigma cross-track error in the shadow position is 9.2 km.
The sky-plane scale is 3598.9 km/arcsec.
Diameter estimates:
92.5 km assuming a 5% albedo, aximum of 5.3 sec for a central chord
37.8 km assuming a 30% albedo, maximum of 2.2 sec for a central chord
Cross-track diameter of 92.5 km used for deployment plan.
Star training set for 4489_Dracius, (2025/04/22 07:40UT) Object RA Dec mag sep mel Pollux 07:46:51.7 +27:57:47 1.1 7.38 155 PPM 073264 07:57:19.5 +35:20:38 6.1 1.40 154 PPM 073087 07:47:19.8 +34:29:32 8.1 1.04 153 PPM 073193 07:53:50.3 +34:53:58 9.8 0.80 154 PPM 073116 07:49:36.7 +35:28:24 10.9 0.24 153 4489_Dracius 07:50:28.8 +35:18:27 14.5 153 Positions are for equinox of date
Star training set for 4489_Dracius, (2025/04/22 07:40UT) Object RA Dec mag sep mel Pollux 07:45:17.8 +28:01:33 1.1 7.38 155 PPM 073264 07:55:40.7 +35:24:45 6.1 1.40 154 PPM 073087 07:45:41.2 +34:33:19 8.1 1.04 153 PPM 073193 07:52:11.7 +34:57:59 9.8 0.80 154 PPM 073116 07:47:57.5 +35:32:16 10.9 0.24 153 4489_Dracius 07:48:49.7 +35:22:21 14.5 153 Positions are for J2000