LtE in CMO #282
From Edward Arnold GRAFTON
@ . . . . . . . .Date:
Tue, 4 Nov 2003 15:59:23 -0600 (CST)
Subject:
Saturn November 4th 2003
Hi Saturn Observers
Here is an observation from
November 4th 2003. There looks to be a small low contrast spot that is near the
CM on the 8:48 UT image. The latitude looks to be about -50 South unlike the
usual interlopers at -42 South. The sky was clear with ground fog moving
through at different densities, the transparency was poor to good 3-8/10, and
seeing was very good 8/10. Light 1 mph South wind and heavy dew with moister
dripping from the surrounding foliage. The weather was mild with the
temperatures in upper 60s F.
Saturn image: http://www.ghg.net/egrafton/11-04-03.jpg
Ed Grafton,
Barlow Projection
to f/27 aprox
.21 arc seconds per pixel.
Image data:
BLUE + IR rejection, 1 second, Edmunds filter
GREEN + IR rejection, .8 seconds, Edmunds filter
RED + IR rejection, .6
seconds, Edmunds filter
Clear
filter, No
IR .3
seconds, Edmunds filter
@ . . . . . . . .Date: Wed, 5 Nov 2003 13:35:41 -0600
(CST)
Subject:
Saturn November 5th 2003
Hi Saturn Observers
Here is an observation from
November 5th 2003. The sky was clear, the transparency was very good 8/10, and
seeing was very good to excellent 9/10. Light 2 mph SE wind and heavy dew. The
weather was mild with the temperatures in upper 60s F.
Saturn image: http://www.ghg.net/egrafton/11-05-03.jpg
Ed Grafton,
Barlow Projection
to f/27 aprox .21 arc seconds per pixel.
Image data:
BLUE + IR rejection, 1 second, Edmunds filter
GREEN
+ IR rejection, .8
seconds, Edmunds filter
RED + IR rejection, .6
seconds, Edmunds filter
Clear
filter, No
IR .3
seconds, Edmunds filter
@ . . . . . . . .Date: Thu, 6 Nov 2003 09:30:38 -0600
(CST)
Subject:
Saturn November 6th 2003
Hi Saturn Observers
Here is an observation from
November 6th 2003. There is a dark feature present to the South of the SEB and
is near the CM on the 09:31 UT immge. It is not clear
what this feature is but may be a cluster of unresolved dark spots or a barge
like feature. The sky was clear with light fog, the transparency was fair to
good 5-8/10, and seeing was very good to excellent 9/10. Light 1 mph S wind and
heavy dew. The weather was mild with the temperatures in upper 60s F.
Saturn image: http://www.ghg.net/egrafton/11-06-03.jpg
Ed Grafton,
Barlow Projection
to f/27 aprox .21 arc seconds per pixel.
Image data:
BLUE + IR rejection, 1 second, Edmunds filter
GREEN + IR rejection, .8 seconds, Edmunds filter
RED + IR rejection, .6
seconds, Edmunds filter
Clear
filter, No
IR .3
seconds, Edmunds filter
@ . . . . . . . .Date: Thu, 6 Nov 2003 20:25:22 -0600
(CST)
Subject:
Re: Saturn November 6th 2003
Hi Saturn Observers
The dark feature in the Saturn
image of Nov. 6th is somewhat of a puzzle to me so I searched for an
explanation. One possibility is that the dark feature is an eddy and the
lighter area following it is left in it's wake. I
found a Voyager 2 image that looked like it could be the same kind of feature
as in the Nov. 6th image. The URL to the voyager 2 image is:
http://www.ghg.net/egrafton/vg2_p239.gif
Any other possible
explanations would be interesting to hear.
@ . . . . . . . .Date: Fri, 7 Nov 2003 11:19:33 -0600
(CST)
Subject:
Update: Saturn November 6th 2003
Hi Saturn Observers
Dr. Agustin Sanchez Lavega has sent along HST images that
clearly shows the structure of the dark area and the following -29
degree white spot that has been well tracked by several observers. The dark
area is most pronounced in the HST 555nm filtered image. The white spot has
more of an amorphous structure in the 675nm HST image. These features also can
be seen in the images on the 10/24 and 10/28 images that Damian Peach sent
along. Please see
Dear
Ed,
Here
is an update of the motion of the spots at -29 deg, and an enlargement of one
of them as captured by the HST at the highest possible resolution. Your dark
spot on November 6 is at the edge of the small white spot (blue track in the
figure).
Note
that whereas the HST spot is "compact" and round in blue (filter 439
nm), it shows structure around it in the other
filters. The spot is located in a weak anticyclonic
flow (and probably it is an anticyclone), and southward (latitudes -35 deg) the
HST images in blue-yellow show a belt with zonal texture. It is probably a
cyclonic more turbulent region, to which your dark spot probably pertains.
I
loose the observers list. Could you send this email to them?
Thanks
a lot and good observations!
Agustin
Ed GRAFTON (