THE BRITISH ASTRONOMICAL ASSOCIATION
SATURN, URANUS AND NEPTUNE SECTION
NOTES & NEWS
11 DECEMBER 2010 TWO BRIGHT SPOTS ON SATURN
A number of spots have been detected on Saturn so far during the current apparition Provisional drift charts for a number of these spots have been derived from section member observations and are shown below.
As noted in an earlier news item, there has been a bright spot visible throughout the apparition in the northern Equatorial Zone (EZ(N)). The drift chart shown below is an update of that shown in the March Notes & News, and this shows the continuation of the spot's positive drift relative to System 1.
Drift chart showing the positions of the centres of the white spots observed in the EZ(N). Longitudes are in System 1.
So far, only a few observations have been made of the dark 'barge' which lies to the north of the South Equatorial Belt (SEB). However a preliminary assessment of these observations indicate that it has a very rapid positive drift of ~11 deg/day with respect to System 1. However further observations are required to establish a reliable drift.
Drift chart of features on the northern edge of the SEB. The preceding, centre and following edges of the dark barge are shown. The longitude system used for this chart is one moving slower than System 1 by 11.1 deg/day.
A white spot has also been observed in the SEB zone (SEBZ) and has a rapid prograde drift with respect to System 3 of ~7.1 deg/day as shown in the following chart.
Drift chart of features in the white spot in the SEB(Z). The longitude system used for this chart is one moving faster than System 1 by 7.1 deg/day.
Finally, the white spot which has been observed north of the South Temperate Belt (STB) at a latitude of approximately -40 degrees is showing a positive drift with respect to System 3.
Drift chart of the white spot which lies north of the STB. Longitudes are in System 3.
March 23. Here is a drift chart from Winjupos for the EZ(N) over the last couple of months and shows the movement in L1 of the centre of the major spot plus the two additional ones discovered by Damian Peach on March 3, 2009..
On the night of March 16/17 Pete Lawrence and David Arditti recorded a dark 'barge' like feature on the northern component to the SEB(N) at l3~ 187. See the Saturn Gallery. Further observations are required.
On March 3 Damian Peach recorded 3 white spots in the EZ(N).
From the UK, Saturn is rising before 23:00 UT, and reaches the meridian at approximately 5:00 a.m.
The tilt of the rings is now under seven degrees allowing more of the northern hemisphere to be visible. Some recent amateur web cam images taken from a number of parts of the world have revealed a small light spot in the STropZ to the south of the SEB at system 3 longitude (L3) ~273 at the beginning of December 2007 and L3 ~ 281 in early January. There have also been reports of a spot in the SEBZ at L3~ 98 in early January.
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