> From egrafton@ghg.net Thu Nov 21 15:52 MST 2002
Date: Thu, 21 Nov 2002 16:51:07 -0600 (CST)
From: egrafton@ghg.net (Ed Grafton)
Subject: Jupiter Observation 11-20-02 10:58 UT
Hi Jupiter Observers
Here is an observation from Houston Texas November 20th 2002 10:58 UT. The
sky was partly cloudy with periods of no clouds, transparency 8/10, and
seeing was good to excellent, 8/10, with a 2mph N. wind. Light dew was
present. The weather was cool with the temperatures in the upper 50s F
around dawn.
Jupiter image :
http://www.ghg.net/egrafton/11-20-02.jpg
Ed Grafton, Houston Texas, ST5C CCD and a 14 inch f/11 Celestron SCT
Barlow Projection to f/27 aprox .21 arc seconds per pixel.
Image data:
10 BLUE + IR rejection, .33 seconds, SBIG filter
10 GREEN + IR rejection, .33 seconds, SBIG filter
10 RED + IR rejection, .33 seconds, SBIG filter
40 clear filter, No IR .11 seconds, SBIG filter
> From egrafton@ghg.net Sat Nov 23 12:03 MST 2002
Date: Sat, 23 Nov 2002 13:01:32 -0600 (CST)
From: egrafton@ghg.net (Ed Grafton)
Subject: Jupiter Observation 11-23-02 10:40 UT
Hi Jupiter Observers
Here is an observation from Houston Texas November 23th 2002 10:40 UT. The
sky was very clear, transparency 9/10, and seeing was good to excellent,
8-9/10, with no wind. Light dew was present. The weather was very cool with
the temperatures in the upper 40s F around dawn.
Jupiter image :
http://www.ghg.net/egrafton/11-23-02.jpg
Ed Grafton, Houston Texas, ST5C CCD and a 14 inch f/11 Celestron SCT
Barlow Projection to f/27 aprox .21 arc seconds per pixel.
Image data:
10 BLUE + IR rejection, .33 seconds, SBIG filter
10 GREEN + IR rejection, .33 seconds, SBIG filter
10 RED + IR rejection, .33 seconds, SBIG filter
50 clear filter, No IR .11 seconds, SBIG filter
>From egrafton@ghg.net Sun Nov 24 15:01 MST 2002
Date: Sun, 24 Nov 2002 16:00:31 -0600 (CST)
From: egrafton@ghg.net (Ed Grafton)
Subject: Jupiter Observation 11-23-02 12:03 UT
Hi Jupiter Observers
Here is an observation from Houston Texas November 23rd 2002 12:03 UT. The
sky was very clear, transparency 9/10, and seeing was good to excellent,
8-9/10, with no wind. Light dew was present. The weather was very cool with
the temperatures in the upper 40s F around dawn.
Jupiter image:
http://www.ghg.net/egrafton/11-23b02.jpg
Ed Grafton, Houston Texas, ST5C CCD and a 14 inch f/11 Celestron SCT
Barlow Projection to f/27 aprox .21 arc seconds per pixel.
Image data: 12 clear filter, No IR .11 seconds, SBIG filter
Thanks
Ed Grafton
> From egrafton@ghg.net Mon Nov 25 20:01 MST 2002
Date: Mon, 25 Nov 2002 21:00:52 -0600 (CST)
From: egrafton@ghg.net (Ed Grafton)
Subject: Jupiter Observation 11-23-02 12:03 UT
Hi Jupiter Observers
The last Jupiter observation that I made on November 23rd had a
feature/configuration that I have not seen before. It is a deflection
or indentation on the N edge of the GRS. The SEBn usually makes a
smooth arc around the GRS but in this image the arc seems to have an
abrupt irregularity. I assume that this characteristic is very
transient, but can someone comment as to what atmospheric dynamics has
caused this and why it is not more commonly seen?
Image:
http://www.ghg.net/egrafton/11-23-02.jpg
Ed Grafton
> From sherrodc@ipa.net Mon Nov 25 20:30 MST 2002
From: "Clay Sherrod"
Subject: Re: Jupiter Observation 11-23-02 12:03 UT
Date: Mon, 25 Nov 2002 21:30:13 -0600
Hello Ed and all....I too noticed this indentation on the n. edge of
the GRS, nearly centered in the ellipse; it is found on two of my
images also from the 23rd, at the ASO Patrol archives at:
http://www.arksky.org/asoimg/jup02_1123b.jpg
and
http://www.arksky.org/asoimg/jup02_1123b.jpg
On the earlier image it almost appears as an overriding of the GRS by
perhaps a higher feature from the SEBn component.
Very interesting morphology both in and around the GRS. Wish the skies
would clear....
Clay
----------------------------------------
Dr. P. Clay Sherrod
sherrodc@ipa.net
Arkansas Sky Observatory
MPC/cbat Obs. H43
www.arksky.org
> From rbeebe@nmsu.edu Tue Nov 26 09:34 MST 2002
Date: Tue, 26 Nov 2002 09:34:16 -0700
Subject: Re: Jupiter Observation 11-23-02 12:03 UT
From: Reta Beebe
In looking at Ed's image it reminded me of a paper published by Elmer
Reese and Brad Smith in the Icarus Journal. In this article they used
an eddy similar to this one to determine the rotation rate of the Red
Spot.
Title: Evidence of vorticity in the Great Red SPOT of Jupiter
Authors: Reese, E. J.; Smith, B. A.
Journal: Icarus, vol. 9, p. 474-486 (1968). (Icarus Homepage)
Publication Date: 11/1968
Origin: AP
Bibliographic Code: 1968Icar....9..474R
These eddies develop in the westward flow along the south side of the
SEB, move around the planet and encounter the Red Spot. They are then
swept into the Red Spot vortex and deflected equatorward around the
spot. When they reach the west ansae they may rejoin the westward SEB
current, be swept around into the eastward flow around the south side of
the Red Spot or even twin and do both. If the eddy moves eastward, as
it approaches the eastern ansae of the Red Spot it may become entrapped
in the northward flow around the eastern end of the Red spot and swept
into the white collar that surrounds the Red Spot. If this happens
frequently, the contrast of the spot relative to its surroundings
decreases.
If you go to
http://photojournal.jpl.nasa.gov and call for images
PIA02259
PIA00489
PIA00488
you will see smaller spots following this path. Sometimes there is even
a triangular structure equatorward of the Red Spot where one of these
eddies is interacting with the 7 deg S eastward current.
Also PIA00011 is a Voyager cylinderical map that you may find useful as
a reference.
Reta Beebe
> From egrafton@ghg.net Tue Nov 26 14:47 MST 2002
Date: Tue, 26 Nov 2002 15:47:43 -0600 (CST)
Hi Reta
Thanks for the informative links and explanation of the dynamics. I found
the animation most enlightning as to the feature noted. One can see that an
eddy sometimes sweeps past the N. edge of the GRS and dipicts itself very
similarly to the observed feature in the 11-23-02 image. In the animation,
one eddy was sweept back into the GRS and changed Red Spot's contrast
considrablbly. It will be interesting to note if the GRS in the coming days
changes it's coloration in response to capturing the eddy or if the GRS just
sends it on its way.
Thanks
Ed Grafton
> From CPAJohnM@aol.com Tue Nov 26 20:47 MST 2002
From: CPAJohnM@aol.com
Date: Tue, 26 Nov 2002 22:46:16 EST
Subject: JUPITER ALERT
ALPO JUPITER ALERT
2002 November 26
Greetings to All,
Regarding Ed Grafton's Jupiter image of November 23rd, showing the
deflection/indentation/eddy on the north edge of the GRS: This is of course
an incredibly detailed image and Ed is to be congratulated for his continued
good works. We are all very proud of him and his work.
A point: in examining some Novemebr 21st and 22nd images from Damian Peach,
this feature does not seem to me to be present. Is it likely that this
feature developed so quickly? It would seem so. This means we need to
continue to followup with imaging of this with a sense of urgency as we
apparently have a fast changing situation. We have a chance to watch the
effects of this in real time if observers can get weather to image. I point
this out because I have heard from so many observers and imagers who are
clouded out as I write this. So, my simple reason for issuing this message
as an alert. Please, if you have clear weather, make a supreme effort to get
GRS images over the next week.
As Ed pointed out, if the GRS incorporates this eddy and loses some of its
intensity as a result, we will have some current clues as to the GRS
darkening and subsequent fading at this time. And, as Dr. Beebe points out,
we have a chance to calculate the current rotation inside the GRS.
Thanks to all,
John
///////////////////////////////////////////
John W. McAnally
The A.L.P.O. Jupiter Section
Assistant Coordinator
Transit Timings