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Events of the Galilean Satellites for July 2011


Table of Events visible from New Zealand for July 2011.

Events of Jupiter's Galilean Satellites

Eclipses, occultations, transits and shadow transit of all four Galilean satellites will be occurring at regular intervals during July. 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. Before opposition, as in July 2011, they occur to the west 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 a little towards the Sun. As a result of the tilt, events behind Jupiter, that is eclipses and occultations appear to take place north of the equator, in the case of Ganymede well north. Events across the face of Jupiter, that is transits and shadow transits appear to take place south of Jupiter's 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 July 2011

The table shows the times (in UT) of events visible from New Zealand for July.
To convert from UT to NZST for times greater than 12 hours UT (as in July) add 1 to the date and subtract 12 hours from the time. Thus July 1 at 15:40 UT is July 2 at 3:40 am NZST.

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
July 1 15:40, 1 ShE 15:48, 2 EcD 16:53, 1 TrE  
July 3 15:47, 2 TrE      
July 5 16:40, 3 OcD 18:39, 3 OcR    
July 7 18:10, 1 EcD      
July 8 15:23, 1 ShI 16:41, 1 TrI 17:33, 1 ShE 18:22, 2 EcD
   July 8 cont 18:50, 1 TrE      
July 9 16:10, 1 OcR      
July 10 15:51, 2 ShE 16:02, 2 TrI 18:29, 2 TrE  
July 12 15:17, 3 EcD 17:33, 3 EcR    
July 15 17:17, 1 ShI 18:37, 1 TrI    
July 16 14:33, 1 EcD 18:07, 1 OcR    
July 17 15:15, 1 TrE 15:55, 2 ShI 18:28, 2 ShE 18:44, 2 TrI
Jun 19 15:27, 2 OcR 19:18, 3 EcD    
July 22 19:11, 1 ShI      
July 23 15:19, 3 TrI 16:27, 1 EcD 17:05, 3 TrE  
July 24 15:01, 1 TrI 15:49, 1 ShE 17:10, 1 TrE 18:33, 2 ShI
July 25 14:31, 1 OcR      
July 26 15:21, 2 EcR 15:38, 2 OcD 18:04, 2 OcR  
July 30 13:30, 3 ShI 15:42, 3 ShE 18:21, 1 EcD  
July 31 15:33, 1 ShI 16:56, 1 TrI 17:43, 1 ShE 19:04, 1 TrE

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