Pluto Occultation July 31, 2007

The northern limit, centerline, and southern limit of Pluto's shadow are shown by the three lines across the globe pictured above. The shaded area represents where the sun is more than 12 degrees below the horizon.

P495.3 Prediction

(as of: 2007 07 12)

Geocentric Mid-time (yyyy month dd hh:mm:ss) 2007 July 31 13:49:28± 00:00:17 UT
Minimum Geocentric Separation 0.239± 0.014 arcsec
Position Angle (Pluto relative to the star; measured north through east) 167.92 degrees
Geocentric Velocity 16.8 km/sec
Prediction Version P495.3-AST-1.5

 

Reference star position:
(UCAC2, at epoch of event)
RA (h:m:s; J2000) Dec (d:m:s; J2000) UCAC Mag1
P495.3 Catalog2 17 45 41.9791 –16 29 31.655 13.3
P495.3 Corrected 17 45 41.9841 –16 29 31.664  

1The UCAC bandpass (579-642nm) is between V and R.

2UCAC2, at epoch of event.

Offsets from Reference Position/Ephemeris3
Body RA (arcsec) Dec (arcsec) Notes

P495.3

+0.0757± 0.0025 –0.009± 0.002 From 105 strip scans
Pluto4

–0.0426± 0.0129

+0.026± 0.014 From 237 strip scans and 89 USNO-61inch Telescope frames.

3All "offsets" are defined in the ("corrected" – "reference") or ("observed" – "calculated") sense. The offsets should be added to reference positions to get the measured positions, which we use to calculate the prediction.

4JPL Horizon's ephemeris (System DE413 - Pluto source file: PLU013; Earth center source file: DE405).

Discussion

Archive of all P495.3 occultation predictions based on alternate sources of data, including past predictions

Site Information

Site
East Longitude
Latitude

Altitude3

(km)

Distance4

(km)

Velocity

(km/s)

Hobart
147 26 24
–42 48 18
0.04
1687 N.
17.0
Mt. John
170 27 50
–43 59 22
1.04
960 N.
16.9
Mt. Stromlo
149 00 35
–35 18 57
0.81
2299 N.
17.0
Siding Spring
149 03 44
–31 16 17
1.21
2672 N.
17.1
Black Spring
138 53 18
–33 53 58
0.47
2729 N.
17.1
Geocentric
----------
---------
---------
5272 N.
16.8

3Altitude of each observatory is measured in kilometers above sea level.

4"Distance" refers to the closest approach distance of the "Site" to the center of Pluto's shadow in the shadow plane. The errors on all closest approach distances are ±305 km (one standard deviation). "S." means the site is South of the center of Pluto's shadow. "N." means the site is North of the center of Pluto's shadow.

P468 Occultation Predictions for Individual Sites

Site
Pluto Immersion (UT)5
Mid-Time (UT)5

Pluto Emersion (UT)5

Hobart
--------
13:47:23 (50°)
--------
Mt. John
13:45:19
13:46:22 (34°)
13:47:25
Mt. Stromlo
--------
13:46:51 (51°)
--------
Siding Spring
--------
13:46:37 (53°)
--------
Black Spring
--------
13:47:29 (34°)
--------
Geocentric
--------
13:49:28
--------

 

5The errors on all times are ±00:00:17 (17 seconds; one standard deviation). In parenthesis is the elevation of the body above the celestial horizon in degrees.

Results of Previous Occultations

Results of the 2006 Pluto occultation are described and compared with results of the 1988 and 2002 occultation in the publication, Changes in Pluto's Atmosphere: 1988-2006

 


Last updated by Carlos A Zuluaga (czuluaga@mit.edu) 2007-07-12 11:30

Please direct all inquiries to Planetary Astronomy Lab (planetary-astronomy@mit.edu)