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Events of the Galilean Satellites for September 2008


Table of Events visible from New Zealand for September 2008.

Events of Jupiter's Galilean Satellites

Eclipses, occultations, transits and shadow transit of all four Galilean satellites will be occurring at regular intervals during September. A table of events visible during the month visible 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. After opposition, as in September 2008, they 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 south pole of Jupiter is tilted slightly towards the Sun so that eclipses and occultations appear to take place to the south of Jupiter's equator. Transits and shadow events appear to take place a little north 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 September 2008

The table shows the times (in UT) of events visible from New Zealand for September. To convert from UT to NZST: if the time is less that 12 hours, add 12 to the hours, or just treat the times as being pm. Thus September 4 at 10:06 UT is 22.06 (10.06 pm) NZST. If the time is 12 hours or more the event occurs after midnight, so add one to the date and subtract 12 from the hours to give NZST am. Thus September 1 at 14:09 UT, is September 2 at 2:09 am NZST.
After the start of NZDT early on the morning of September 28, for times before 11 hours add 1 hour and treat the time as being pm NZDT. Thus September 28 at 07:18 UT is September 28 at 8:18 pm NZDT. If the time is great than 11 hours UT add 1 to the date and subtract 11 hours. This 13:14 UT on September 30, is October 1 at 2:14 am NZDT.

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
September 2 14:09, 3 TrI 15:38, 1 TrI    
September 3 12:46, 1 OcD 16:10, 1 EcR    
September 4 10:06, 1 TrI 11:14, 1 ShI 12:22, 1 TrE 13:30, 1 ShE
September 5 07:13, 1 OcD 10:39, 1 EcR 13:50, 2 TrI  
September 6 06:50, 1 TrE 07:12, 3 OcR 07:59, 1 ShE 08:37, 3 EcD
    Sep. 6 cont. 11:58, 3 EcR      
September 7 08:51, 2 OcD 09:37, 4 TrI 13:16, 4 TrE 14:01, 2 EcR
September 9 08:10, 2 ShE      
September 10 14:36, 1 OcD      
September 11 11:57, 1 TrI 13:09, 1 ShI 14:13, 1 TrE 15:25, 1 ShE
September 12 09:04, 1 OcD 12:34, 1 EcR    
September 13 07:38, 1 ShI 07:41, 3 OcD 08:41, 1 TrE 09:54, 1 ShE
    Sep. 13 cont. 10:57, 3 OcR 12:37, 3 EcD    
September 14 07:03, 1 EcR 11:21, 2 OcD    
September 16 07:23, 4 EcD 08:01, 2 ShI 08:16, 2 TrE 10:46, 2 ShE
    Sep. 16 cont. 11:29, 4 EcR      
September 18 13:50, 1 TrI 15:05, 1 ShI    
September 19 10:56, 1 OcD 14:30, 1 EcR    
September 20 08:18, 1 TrI 09:34, 1 ShI 10:34, 1 TrE 11:30, 3 OcD
    Sep. 20 cont. 11:50, 1 ShE 14:46, 3 OcR    
September 21 08:59, 1 EcR 13:53, 2 OcD    
September 23 08:04, 2 TrI 10:37, 2 ShI 10:48, 2 TrE 13:23, 2 ShE
September 24 10:02, 3 ShE 14:45, 4 ShI    
September 25 08:34, 2 EcR      
September 26 12:50, 1 OcD      
September 27 10:12, 1 TrI 11:29, 1 ShI 12:27, 1 TrE 13:45, 1 ShE
September 28 07:18, 1 OcD 10:54, 1 EcR    
September 29 08:14, 1 ShE      
September 30 10:38, 2 TrI 13:14, 2 ShI 13:22, 2 TrE  

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