 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. |
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| Offsets
from Reference Position/Ephemeris3 |
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| 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). |
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Discussion
On July 31st, 2007, Pluto will occult P495.3 (= 2UCAC 25815762; as originally published in McDonald & Elliot, 2000; Table). The above map and the following prediction results are from the analysis of 237 strip scans obtained at the Lowell Observatory Astrograph by Rosemary Pike, Amanda Bosh, and Allison Moberger during 2005-2007 (the strip scans from earlier years did not contain Pluto-Charon images) and 89 frames taken on 2005 and 2007 by Steve Levine with the 1.55-m Kaj Strand Astrometric Reflector.
Proper motion of the star has been applied up to the time of the occultation (according to the UCAC2 catalog, dRA: –10.8± 7.9 mas/yr, dDec: –3.3± 7.9 mas/yr). The offsets between the measured RA and Dec of P495.3 and its UCAC2 values at the time of the event are also given in the table.
Prediction Notes
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)
