P571 Occultation June 24, 2008

(last updated 2008 06 21)

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.

 

Geocentric Mid-time (yyyy month dd hh:mm:ss) 2008 June 24 10:36:35± 00:00:10 UT
Minimum Geocentric Separation 0.017± 0.016 arcsec
Position Angle (Pluto relative to the star; measured north through east) –4.13 degrees
Geocentric Velocity 23.7 km/sec
Prediction Version P571-AST-3.0


 

Reference star position:
(USNO-B1.0, at epoch of event)
RA (h:m:s; J2000) Dec (d:m:s; J2000) R Mag1
P571 Catalog2 17 58 22.3687 –17 02 49.150 15.8
P571 Measured3 17 58 22.3951 –17 02 49.347  

1From USNO-B Catalog.

2USNO-B, at epoch 1972.9.

3Using 49 frames obtained by Steve Levine with the 1.55m telescope at the United States Naval Observatory.

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

P571

+0.3878± 0.0005 –0.197± 0.001 From 49 USNO Frames
Pluto5

–0.0509± 0.014

+0.096± 0.017 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).

6255 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

Site Information

Site
East Longitude
Latitude

Altitude7

(km)

Distance8

(km)

Velocity

(km/s)

Flagstaff
–111 44 23
35 11 02
2.31
315 S.
23.99
Hobart
147 26 24
–42 48 18
0.043
6826 S.
23.95
IRTF
–155 28 29
19 49 46
4.18
121 S.
24.17
Las Campanas
–70 42 00
–29 00 30
2.28
7222 S.
23.74
Lick Obs.
–121 38 12
37 20 36
1.29
703 N.
24.03
Magdalena Ridge Obs.
–107 11 05
33 58 36
3.18
106 S.
23.97
Mt. John
170 27 50
–43 59 22
1.041
6717 S.
24.03
Siding Spring
149 03 44
–31 16 17
1.205
5637 S.
23.99
Geocentric
----------
---------
center of Earth
3862 S.
23.74

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 ±443 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.

P571 Appulse Predictions for Individual Sites

Site
Pluto Immersion (UT)9
Mid-Time (UT)9

Pluto Emersion (UT)9

Solar Elevation 10
Flagstaff
10:32:35
10:33:33 (18°)
10:34:32
–16°
Hobart
-----------
10:39:15 (42°)
-----------
–42°
IRTF
10:34:54
10:35:53 (18°)
10:36:52
–47°
Las Campanas
-----------
10:32:48 (6°)
-----------
–12°
Lick Obs.
10:33:11
10:34:03 (18°)
10:34:55
–20°
Magdalena Ridge Obs.
10:32:21
10:33:21 (18°)
10:34:20
–15°
Mt. John
-----------
10:38:11 (56°)
-----------
–59°
Siding Spring
-----------
10:39:31 (45°)
-----------
–44°
Geocentric
-----------
10:36:35
-----------
 

9The errors on all times are ±0:10 (10 seconds; one standard deviation). In parenthesis is the elevation of the body above the celestial horizon in degrees.

10At the closest approch time for that location.

** Internal note: A– (20080404) **


Last updated by Carlos A Zuluaga (czuluaga@mit.edu) 2009-04-06 08:30

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