P634 Occultation June 10, 2009

(last updated 2009 03 17)

The shaded area represents where the sun is more than 12 degrees below the horizon. Across the globe pictured above, the three lines correspond to the northern limit, centerline, and southern limit of Pluto's shadow. The northern and southern limits correspond to a radius of 1208 km (the 50% normalized stellar-flux level) for Pluto. The dashed lines represent the upper and lower limits for the track given the prediction error listed on this page.

 

Geocentric Mid-time (yyyy month dd hh:mm:ss) 2009 June 10 15:21:38± 00:00:56 UT
Minimum Geocentric Separation 0.1422± 0.0575 arcsec
Position Angle (Pluto relative to the star; measured north through east) –3.25 degrees
Geocentric Velocity 23.09 km/sec
Prediction Version P634-AST-1.0

 

Reference star position:
(USNO-B1.0, at epoch of event)
RA (h:m:s; J2000) Dec (d:m:s; J2000) R Mag1
P634 Catalog2 18 09 03.3007 –17 38 33.746 15.5
P634 Measured 18 09 03.2921 –17 38 33.600 16.73

1From USNO-B Catalog.

2USNO-B, at epoch 1970.3.

2UCAC2 2006 Catalog

Offsets from Reference Position/Ephemeris4
Body RA (arcsec) Dec (arcsec) Notes

P634

–0.1278± 0.0580 +0.146± 0.055 From 5 Strips
Pluto5

–0.0478± 0.0112

+0.143± 0.015 See note 6

4All "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.

5The reference position for Pluto is that given by JPL Horizon's ephemeris (Pluto source file: PLU017; Earth center source file: DE405).

6315 strip scans and 89 USNO-61inch Telescope frames were used to develop a model to fit the residuals obtained from our measured positions compared to that of the object's JPL ephemeris.. The model includes the first-order effects of errors in the orbital elements of Pluto: (i) constant offsets in RA and Dec, (ii) linear (in time) offsets in RA and Dec, (iii) sinusoidal terms with the Earth's orbital period, and (iv) sinusoidal terms with the Pluto-Charon mutual orbit.

Discussion

Prediction Notes

Site Information

Site
East Longitude
Latitude

Altitude7

(km)

Distance8

(km)

Velocity

(km/s)

ARIES (Naini Tal)
+79 27 24
29 21 42
1.927
678 N.
23.30
Bosscha Obs.
+107 37 00
–06 49 30
1.300
2273 S.
23.49
Girawali Observatory
+73 40 00
19 05 00
1.005
370 S.
23.28
Indian Astro. Obs.
+78 57 54
32 46 48
4.467
940 N.
23.29
Purple Mountain Obs.
+118 49 18
32 04 00
0.267
1478 N.
23.46
Vainu Bappu Obs.
+78 49 36
12 34 36
0.725
855 S.
23.32
Geocentric
----------
---------
center of Earth
3339 S.
23.09

7Altitude of each observatory is measured in kilometers above sea level.

8"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 ±1278 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.

P634 Occultation Predictions for Individual Sites

Site
Pluto Immersion (UT)10
Mid-Time (UT)10

Pluto Emersion (UT)10

ARIES (Naini Tal)
15:24:08
15:25:01 (14°)
15:25:54
Bosscha Obs.
-----------
15:24:10 (54°)
-----------
Purple Mountain Obs.
-----------
15:22:59 (35°)
-----------
Girawali Observatory
15:24:34
15:25:32 (14°)
15:26:30
Indian Astro. Obs.
15:24:09
15:24:54 (12°)
15:25:38
Vainu Bappu Obs.
15:24:44
15:25:32 (21°)
15:26:19
Geocentric
-----------
15:21:37
-----------

10The errors on all mid-times are ±0:56 (56 seconds; one standard deviation). In parenthesis is the elevation of the body above the celestial horizon in degrees.

11At the closest approch time for that location.


Last updated by Carlos A Zuluaga (email) 2009-03-17 12:30

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