Jupiter 8/1/06

Anyone view Jupiter last night (8/1/06)? If so did you notice a small dark
oval moving along the north equitorial band from 22:00 CDT (03:00 GMT) to
23:00 CDT? It initially looked like a shadow of a moon but my software
indicates that there was no shadow at the time, and the dark oval seemed to
be flattened, rather than round. North-south it seemed to be about the same
size as a moon shadow but was about twice as wide on the East West axis.
Here is my observing report:

"C10 NGT at 200X. N&S Eq bands evident. Swirling in Eq zone. 22:08:
observed small black blotch on southern edge of N Eq band. Initially thought
it might be a moon shadow, but no shadowing at that time. Blotch was a
flattened oval about 5 deg. E of meridian. Reobserved at 22:49L. Blotch
still evident on S. edge of N. Eq band, this time abut 20 deg from W limb.
Blotch was followed by a larger white oval which seemed to touch black
blotch and extend to the meridian, i.e. trailing edge of white oval was on
the meridian and leading edge W. of meridian, touching black spotch. White
oval looked a bit like Great Red Spot in shape but was about 3/4 it's size.
No color on planet noted, so objects mentioned could be colored instead of
black and white. 4 Jovian moons evident W/ 20 mm (60X)."
Thanks.

-John

"John Banister" wrote in message
...
Anyone view Jupiter last night (8/1/06)? If so did you notice a small
dark oval moving along the north equitorial band from 22:00 CDT (03:00
GMT) to 23:00 CDT?

Congratulations, you have seen the Great Red Spot, which transited at the
following UTC times on 8/1 and 8/2/2006:

August 1, 0:57, 10:53, 20:48
Aug 2, 6:44, 16:40

See the Sky & Telescope homepage for their Jupiter observing tips. They
have a calculator and a list of GSR transit times for the rest of the year.
and a list of all the transit for the remainder of this calendar year.

http://skyandtelescope.com/observing...icle_107_1.asp
http://skyandtelescope.com/observing...icle_107_1.asp

- Canopus56

"John Banister" wrote in message
...
snip
Either that, our you are talking about the Great Red Spot, Jr. , also
discussed at the S&T site. - C

Kurt (canopus56) wrote:
Congratulations, you have seen the Great Red Spot, which transited at the
following UTC times on 8/1 and 8/2/2006:

I don't think so. John said the object he observed was in the northern
equatorial belt, not the southern. And even if he got north and south
mixed up, he said that the object was at the *southern* edge of the
*northern* equatorial belt--that is, it was toward the equator from the
center of the belt. The GRS is on the southern edge of the SEB, *away*
from the equator.

I don't know what it was; I'm afraid to say I only observed Jupiter with
binoculars yesterday.

--
Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html

Anyone view Jupiter last night (8/1/06)? If so did you notice a small dark
oval moving along the north equitorial band from 22:00 CDT (03:00 GMT) to
23:00 CDT?

Yes, I did. I was viewing at between 0230 and 0345 UT on August 2nd
(UT) using a 4 inch refractor at about 143x and noted a small darkening
almost in the middle of the north equatorial belt. Seeing wasn't good
enough to try higher power, but the small darkening was there. Clear
skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 13th Annual NEBRASKA STAR PARTY *
* July 23-28, 2006, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

canopus56 wrote:
"John Banister" wrote in message
...
snip
Either that, our you are talking about the Great Red Spot, Jr. , also
discussed at the S&T site. - C

No way; GRS Jr is not very dark and is difficult to detect w/o
good seeing.

DC

John Banister wrote:
Anyone view Jupiter last night (8/1/06)? If so did you notice a small dark
oval moving along the north equitorial band from 22:00 CDT (03:00 GMT) to
23:00 CDT? It initially looked like a shadow of a moon but my software
indicates that there was no shadow at the time, and the dark oval seemed to
be flattened, rather than round. North-south it seemed to be about the same
size as a moon shadow but was about twice as wide on the East West axis.
Here is my observing report:

"C10 NGT at 200X. N&S Eq bands evident. Swirling in Eq zone. 22:08:
observed small black blotch on southern edge of N Eq band. Initially thought
it might be a moon shadow, but no shadowing at that time. Blotch was a
flattened oval about 5 deg. E of meridian. Reobserved at 22:49L. Blotch
still evident on S. edge of N. Eq band, this time abut 20 deg from W limb.
Blotch was followed by a larger white oval which seemed to touch black
blotch and extend to the meridian, i.e. trailing edge of white oval was on
the meridian and leading edge W. of meridian, touching black spotch. White
oval looked a bit like Great Red Spot in shape but was about 3/4 it's size.
No color on planet noted, so objects mentioned could be colored instead of
black and white. 4 Jovian moons evident W/ 20 mm (60X)."
Thanks.


What you observed is very likely a festoon (there are 13 of them) as
they can be quite dark where they touch the NEBs (let's say at their
"root"). Some, but not all, are accompanied by a bright ammonia spot (a
source) so what you observed is quite plausible.

Andrea T.

Thanks, that agrees with what I saw, but my seeing allowed higher power.
The Moon, in the same general area of the sky, easily allowed 300X.

I wonder what this darkening was? My extimate is that it passed the meridian
at approx. 03:20 GMT, which would pit it 3.5 hours ahead of the Great Red
Spot, according to my software. If that relationship holds true, it will
not be visible from my site tomorrow but should be viewable around midnight
(05:00 GMT) Thurs night. Jupiter is quite low then, so we'll see. Maybe
someone away from North America can give it a try.

-John

"David Knisely" wrote in message
...
Anyone view Jupiter last night (8/1/06)? If so did you notice a small
dark oval moving along the north equitorial band from 22:00 CDT (03:00
GMT) to 23:00 CDT?

Yes, I did. I was viewing at between 0230 and 0345 UT on August 2nd (UT)
using a 4 inch refractor at about 143x and noted a small darkening almost
in the middle of the north equatorial belt. Seeing wasn't good enough to
try higher power, but the small darkening was there. Clear skies to you.

Thanks, but it wasn't the GRS. Wrong side of the equator. I try and view
that at least once a week lately, when conditons allow. Jupiter had pretty
much set by the time the GRS came around.

-John

"canopus56" wrote in message
...
"John Banister" wrote in message
...
Anyone view Jupiter last night (8/1/06)? If so did you notice a small
dark oval moving along the north equitorial band from 22:00 CDT (03:00
GMT) to 23:00 CDT?

Congratulations, you have seen the Great Red Spot, which transited at the
following UTC times on 8/1 and 8/2/2006:

On the subject of GRS Jr., I've only nailed it once, about 6 weeks ago, and
it's getting harder and harder to even give it a try. It either passes too
early when it's not twilight or too late when Jupiter has descended in the
west where seeing is poor and light polution is the greatest from my side.
Now it (and Sr.) seems to only hit a proper window (around 9:30 local) on
Wednesdays, and I'm gone that night.

Can anyone do something about that? ;-)

-John

"canopus56" wrote in message
...
"John Banister" wrote in message
...
snip
Either that, our you are talking about the Great Red Spot, Jr. , also
discussed at the S&T site. - C