Pluto Occultation of P131.1

Ron Stone has provided new astrometric measurements of this star from observations at the FASTT at the U.S. Naval Observatory, which were averaged with unpublished UCAC** values for the position to calculate the offsets given below. The offset is relative to the star's published position, as determined by McDonald and Elliot (see AJ 120 2000)***. The Pluto offsets to its ephemeris were estimated from Pluto's recent occultation with P126 in July 2002. Results for Pluto are tabulated as offsets from the unmodified light-time corrected, geocentric JPL Horizon's ephemeris (PLU006 and DE-0406, LE-0406).

Reference Position (2.0)***	RA (J2000)	Dec (J2000)	R Mag*
P131.1	16 58 49.456	-12 51 31.41	15.65
Offsets from Reference
Body	RA (arcsec)	Dec (arcsec)
P131.1	+ 0.312+/– 0.103	– 0.428+/– 0.089
Pluto	– 0.02 +/– 0.007	– 0.023 +/– 0.007

* From Ron Stone's reduction

**Zacharias, UCAC unpublished

*** McDonald 2000 AJ 120 1599

	P131.1 Current Prediction (as of 2002 07 26 1:39 PM EDT)
Date and Time (yyyy mm dd hh:mm:ss)	2002 08 21 06:57:07 UT
Minimum Geocentric Separation (arcsec)	0.02 +/- 0.101
Position Angle (in degrees, clockwise from East)	117
Geocentric Shadow Velocity (km s-1)	6.7
Star Magnitude	15.7 (V)
Solar Angle (deg)	107
East Longitude (deg)	-179
Distance (AU)	30.24
Prediction Version	p131.1-2.2

Prediction Notes

• The separation between the center line and each of the limb lines is an estimated Pluto atmospheric half-light radius. (1160 km after correction for refraction by Pluto's atmosphere.)
• The ephemeris used in this prediction is that generated for Pluto with JPL's Horizon's Ephemeris service (corrected for Light Travel time). The Pluto offset was calculated using data from its occultation with P126A on July 20 2002.

Archive of past P131.1 occultation predictions.

Pluto Occultation Predictions for Individual Sites

Last updated by Katie Carbonari (kcarbon@mit.edu) 2002 07 17 1:05 PM EDT

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