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Events of the Galilean Satellites for October 2011


Table of Events visible from New Zealand for October 2011.

Events of Jupiter's Galilean Satellites

Eclipses, occultations, transits and shadow transit of all the three inner Galilean satellites will be occurring at regular intervals during October. A table of events visible during the month from NZ is included.

Eclipses occur when a satellite moves through the shadow of Jupiter. As it moves into the shadow the satellite will gradually fade from view and disappear. When it comes out of the shadow a faint spot of light will appear and gradually brighten.
Occultations occur when a satellite moves behind Jupiter as seen from the Earth. Hence during an occultation the satellite is hidden by the planet.
Transits occur when a satellite moves across the face of Jupiter as seen from the Earth.
Shadow transits occur when the shadow of the satellite cast by the Sun moves across the face of the planet

Occultations always start at the western limb of Jupiter and end at the east. Transits always start at the eastern limb of the planet and end at the west. In both cases the satellite will appear to "sink" into the bright limb of Jupiter at the ingress and gradually emerge from the limb of Jupiter at an egress.

In general eclipse events take place when the satellite is a small distance away from Jupiter as seen from the Earth, although they will occur very close to the planet near the time of opposition, as at the end of October. Before opposition, as in most of October, events occur to the west of the planet. After opposition on October 29, eclipse events occur to the east of the planet.

All these events can be observed through a small telescope. Note that when Jupiter is viewed through an undriven telescope its image will drift to the west. This enables the west side of the planet to be determined.

In the case of disappearances into eclipse (EcD) the satellite is likely to be visible as it fades for a minute or two after the predicted time. For reappearances (EcR) the satellite will start to emerge a minute or two before the predicted time.

At present the north pole of Jupiter is tilted slightly towards the Sun. As a result of the slight tilt eclipses and occultations appear to take place to the north of the planet's equator, especially noticeable for the outer two satellites. Transits and shadow transits will cross the planet south of the equator. From New Zealand Jupiter's north pole is the lower pole of the planet.

Table of Galilean Satellite events visible from New Zealand for October 2011

The table shows the times, in UT, of events visible from New Zealand for October. To convert times to NZDT: for times after 11 hours UT, add 1 to the date and subtract 11 hours. Thus October 1, 14:09 UT is 3:09 am NZDT on October 2. For time less than 11 hours UT, add 1 to the hours and take the time as pm NZDT. Thus October 3 at 09:18 is 10.18 pm NZDT on October 3.

Times of events are adapted from those given by Dave Herald's OCCULT 4 program.

Explanation:
Satellites: 1 = Io, 2 = Europa, 3 = Ganymede, 4 = Callisto.
EcD = Eclipse disappearance, EcR = Eclipse reappearance
OcD = Occultation disappearance, OcR = Occultation reappearance
TrI = Transit Ingress (start), TrE = Transit Egress (end)
ShI = Shadow transit start, ShE = Shadow Transit end.

Date Time UT,  Event Time UT,  Event Time UT,  Event Time UT,  Event
October 1 14:09, 1 ShI 14:52, 1 TrI 16:20, 1 ShE 17:00, 1 TrE
October 2 11:29, 1 EcD 14:20, 1 OcR    
October 3 09:18, 1 TrI 10:48, 1 ShE 11:26, 1 TrE  
October 5 14:45, 2 EcD      
October 6 15:32, 3 EcD      
October 7 09:56, 2 ShI 11:07, 2 TrI 12:25, 2 ShE 13:28, 2 TrE
October 8 16:03, 1 ShI 16:36, 1 TrI    
October 9 13:24, 1 EcD 16:04, 1 OcR    
October 10 09:18, 3 TrE 13:32, 1 ShI 11:02, 1 TrI 12:43, 1 ShE
  Oct 10 cont. 13:11, 1 TrE      
October 11 10:30, 1 OcR      
October 14 12:32, 2 ShI 13:21, 2 TrI 15:01, 2 ShE 14:43, 2 TrE
October 16 09:47, 2 OcR 15:18, 1 EcD    
October 17 09:43, 3 ShI 11:19, 3 TrI 11:44, 3 ShE 12:27, 1 ShI
  Oct 17 cont. 12:37, 3 TrE 12:46, 1 TrI 14:38, 1 ShE 14:55, 1 TrE
October 18 09:47, 1 EcD 12:14, 1 OcR    
October 19 09:06, 1 ShE 09:21, 1 TrE    
October 21 15:08, 2 ShI 15:35, 2 TrI    
October 23 09:18, 2 EcD 12:02, 2 OcR    
October 24 13:44, 3 ShI 14:21, 1 ShI 14:29, 1 trI 14:33, 3 TrI
  Oct 24 cont. 15:45, 3 ShE 15:54, 3 TrE 16:32, 1 ShE 16:39, 1 TrE
October 25 11:42, 1 EcD 13:57, 1 OcR    
October 26 08:50, 1 ShI 08:55, 1 TrI 11:01, 1 ShE 11:04, 1 TrE
October 27 08:23, 1 OcR      
October 29 Jupiter at opposition
October 30 11:53, 2 OcD 14:25, 2 EcR    
October 31 16:13, 1 TrI 16:16, 1 ShI    

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