Observations with small telescopes
From the newsgroup sci.astro:
Last night, around 04:20 UT (July 18), I observed two dark spots at
high (roughly 45-50 degrees) southern latitudes. The preceding spot
was ink black, and elongated north-south. The following spot was
brownish, larger, and more diffuse. The following spot transited
at 04:45 (plus-minus five minutes). Anyone know where to find a
table of System II longitudes for 0 h UT?
The observations were made with an 11 inch (28 cm) SCT.
Also observed the previous night during fragment B's impact, but
saw nothing unusual.
Clear skies,
Bill
bdillon@houston.geoquest.SLB.com
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It seems amateur astronomers are in luck! I saw a row of 3 dark impact
spots caused by fragments A, C, and E from outside Tucson on July 17 at
10:00pm PDT (July 18th 5:00 UT) using an 8" telescope. I think experienced
amateurs with smaller telescopes may have a good chance of seeing effects,
especially if more impacts create a chain or even band of dark spots!
I made a sketch of Jupiter when I saw the 3 spots. I found the sites did
reasonably match the positions predicted by the tracker3 program so I won't
describe them in detail. The darkest and most visible spot might actually
have been a combination of E and F aftermaths. I couldn't tell because it
was near the exit limb and because of resolution limits. The next darkest
was C, toward the entrance limb. Lastly was A, a bit off center toward the
exit limb. Site A was not quiet as dark as C.
I could not really estimate the sizes or true darknesses. It's hard to
tell the difference between a very dark, sharp spot that is blurred by
resolution limits and a grey spot that really is fuzzy. I could easily see
the two main southern bands of Jupiter but the 3rd was hard to discern. My
telescope is a 200mm (8") F/10 S-C. I was using 330x magnification.
While setting up, and at a lower magnification (110x), I only noticed one
spot, which was close to center then (3:30 UT). I wonder if I was seeing a
combination of E and F, which should be fairly close to each other relative
to the apparent sizes of the spots.
When I'm grey I can say "I saw Jupiter transformed by a comet". :-)
/-\ |_ |= >< Alex R. Gibbs arg@kilimanjaro.opt-sci.arizona.edu
"Never fear, there's a place where you are safe. You don't have to be real
or have a face. My time's too short to waste on things you say without
your brain. Will you paint works of art when you speak?"
-- Happy Rhodes, "Word's Weren't Made for Cowards"
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Dan Bruton (wdb3926@zeus.tamu.edu) wrote:
:Three dark features were observed visually tonight using a36cm(f/11)Schmidt-
: Cassegrain Telescope. The first crossed the central meridian of Jupiter
: at 3:50 UT, July 18, 1994 and appeared almost like a Galilean moon shadow
: (roughly 6000 km in diameter). There was an irregular feature to the
: south-preceding edge of this dark spot. Perhaps the dark spot
: and irregular feature were the impact sites of F and/or E.
Confirmed! A group of astronomy club members in central Missouri
witnessed the same event starting at 02:30:00 UTC on July 18th with a
darkening of the southeastern limb. This darkening resolved itself to be a
very dark spot reminding us of a shadow transit. This first dark spot crossed
the Jovian meridian at approx. 03:30:00 UTC.
At approx. 03:15:00 UTC we detected a new spot, very similar to the first,
coming into view. This second spot seemed to be not as dark as the first
spot, but was thought by several observers to be a bit larger and possibly
oval shaped. This spot crossed the meridian at approx. 04:45:00 UTC.
The first spot was "discovered" in a 6" reflector and was even visible in
a 80mm refractor. A senior member of the group was quoted as saying
"I've looked at Jupiter for 30 years and have never seen anything like that".
Andy Steere (dmislas@clark.umsystem.edu)
Central Missouri Astronomical Association
Columbia, Missouri (USA)
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In article <30durm$8et@vixen.cso.uiuc.edu>, dnash@uxa.cso.uiuc.edu (Dave Nash) w
rites...
>Yet another black spot sighting:
>These features are well
>within the reach of small scopes.
I just saw a dark smudge! First sighted at 9:50 PM (Jul 19 4:50 UT)
near the limb at about the 1 o'clock position in an inverted image.
(Near where the impacts are supposed to be happening).
This was with a crappy 60 mm scope! Yes, a beat-up Department-store
trash job that is at least 15 years old!!
Donald Arseneau asnd@reg.triumf.ca
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In article <30e3qk$ka5@tequesta.gate.net>, dhearn@gate.net (David) wrote:
> I observed the impact remnants of fragment F of SL9. The observation
> was at 02:30 UT from Orlando, FL. The instrument used was a 17.5"
> Newtonian, with a Nagler 9mm eyepiece (240x) and a #80A light blue
> filter. Transparency was good to excellent, with little atmospheric
> disturbances
I viewed the new black spot (assumably fragment F) from St. Louis, MO at
the 02:10 UCT in the southern belt. It rotated into center view a while
later. I viewed with a SC 10" scope - no filter used. I could see the spot
clearly with my ultra wide 8.8 meade eyepiece (181x) also with a 26mm
eyepiece with a 2x barlow. The spot was very noticeable. In addition,
neighbors of mine whom never viewed Jupiter pointed the spot out in the
correct place.
--
--+ --
0=/ || 0=/ | Brian Cherkas
--------------------/TWA| -----------------------
(@ ooo ooooo oooooo ooo > cherkas@crl.com
-------- ----- / compuserve/73644,1444
0=\ || \__|
\--+
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Navarun Gupta: G (H?) spot observed from Atlanta 18 Jul 1994 22:06
I am amazed at the size of this spot. I just came in to post this
article. Its still visible and should cross the meridien soon (within an
hour).
I am watching from the city of Atlanta, its 10:05 PM Local time. I am
using a C8 with a 80X !
Navarun
--
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HATE = IS NOT A FAMILY VALUE
ngupta@dekalb.dc.peachnet.edu
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James Lancashire: H observed from Cambridge, UK 18 Jul 1994 23:07
Central part of impact site H crossed Jupiter's central meridian at
2214 +- 4 UT on 1994 July 18, corresponding to a system 2 longitude of
23 +- 2 deg.
Seeing was IV on the Antoniadi scale. Telescope was 200 mm f/14 refractor
(`Thorrowgood') with 12.5 mm eyepiece (giving magnification of x160) at
The Observatories, University of Cambridge, UK.
The impact longitude is close to that predicted by Chodas. Despite continued
visual monitoring of the planet and the favourably-placed jovian satellites
I & III from 1915 UT for an hour, nothing of the impact itself was seen. An
indentation in the following limb was suspected at 2028 UT and confirmed
independently at 2030 UT. The observer suspects a fading of impact site H
as it rotated from the limb to central meridian. The transit timing was made
with the planet at low altitude.
James Lancashire
Affiliations (in some order):
Cambridge University Astronomical Society
British Astronomical Association
Editor, `The Comet's Tale' (BAA Comet Section Newsletter)
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Steve Gilham: >H observed from Cambridge, UK 19 Jul 1994 07:55
James Lancashire (jalan@mail.ast.cam.ac.uk) wrote:
> Central part of impact site H crossed Jupiter's central meridian at
> 2214 +- 4 UT on 1994 July 18, corresponding to a system 2 longitude of
> 23 +- 2 deg.
Well, that reassures me that what I and 4 others saw an hour or so
earlier (between 2045 and 2115 UT) from just north of St. Neots was a
real feature. Using a 100mm Vixen refractor with a 5mm eye-piece (200x
magnification), a trifle more than the seeing could really stand, it
was clear that there was an anomalous feature in mid southern
latitudes, moving from near the limb. It was just at the limits of
seeing, needing averted vision to increase the sensation of contrast,
and gave the impression of being coloured a blackish-blue, almost like
a bruise - quite unlike the normal cream and russet colour scheme.
There was a faint suggestion of indentation of the limb on first
acquisition of the planet, but this did not persist, and was not
remarked upon by any of the other observers. The other experienced
observer of the group was quite confident in confirming my impression
that even with this small 'scope we were seeing something that didn't
actually belong in the normal scheme of things.
-----------------------------------------------------------------------------
Steve Gilham |GDS Ltd.,Wellington Ho. |Lives of great men all remind us
Software Specialist|East Road, Cambridge |We may make our lives sublime
steveg@ |CB1 1BH, UK |And departing, leave behind us
arc.ug.eds.com |Tel:(44)223-314041 x304 |Footprints in the sands of time.
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N Clifford: >H observed from Cambridge, UK Tue, 19 Jul 1994 11:45
I and 8 others saw a large sooty black feature in the southern hemisphere
whilst observing yesterday. Using 12 in and 8 3/4 in reflectors (sorry don't
have the full details with me) as part of a party viewing from the Derby and
district astron soc. observatory (some 10 miles wnw of Derby) acquired Jupiter
in the daylight at approx 2025 BST, using a polarizing filter to improve
visibilty of details. We noticed the feature which in our estimation was
'blurred' to a size easily comparable to the great red spot. We followed it's
motion across the planet till it's disappearance at the limb around 2230 BST
at which time two observers believed they could see a much fainter black feature
of smaller size than the first at the same latitude coming into view over the
limb.
I must remeber to run the tracker3 program from Texas A&M Univ. backwards to
attempt to identify the fragments which may have resulted in these features.
All in all good fun, and a great introduction for several new members.
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INTERNET: clifford@festival.ed.ac.uk <> JANET: N.T.Clifford@uk.ac.ed
SNAIL: N.Clifford, Meteorology Dept., Edinburgh Univ., Edinburgh,Scotland
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Jarle Brinchmann: H observed in Norway. 18 Jul 1994 22:05
Hi,
Here in Norway we observed the G-spot on Jupiter at 19.45 UT with a
Celestron 8 (most easily spotted using a yellow filter). The spot crossed
the central meridian at 20.20 UT. Since then
a group of amateurs at Sollihoegda a bit outside Oslo reported visual
observation of the impact aftermath of H at 21.00 UT, this detection was
done with a 10 inch telescope. There are some
indications that H have been observed also with the Celestron 8, but
the seeing started to get so bad that the detections are uncertain.
Early observation from the Nordic Optical Telescope (NOT) on the La
Palma indicate that the H-impact was reported by Marek Jablonski to be
about 5-10 times as bright as the A-impact saturday.
If you have a 8 inch or more, you should go out and observe, we had poor
conditions here in Norway (the sun goes down almost together with Jupiter),
so anyone with better conditions will probably have a fair chance to see
something.
Jarle.
---------------------------------------------------------------------
Nuke the Whales ! | Jarle Brinchmann,
| Email: Jarle.Brinchmann@astro.uio.no
International Krill Union. | or : jarleb@astro.uio.no
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michael boschat: Impact area G seen in 4" refractor Tue, 19 Jul 1994 00:39
Just before we became overcast, I caught a glimpse of the dark area
caused by the G fragment. It looked like a satellite shadow transit
and was just a bit past Jupiter's Central Meridian. Then, the clouds
wiped out everything...but saw it !
The Jovian coordinates were; System 1= 31.44 degrees
System 2= 300.45 degrees
I used a 4 in f/9, refractor at 167x, no filters used. Tried a light blue
but found that just visual showed the spot better. My location, Halifax,
Nova Scotia, Canada lat= 44 N long= 63 W height 58 meters above sea
level.
Get out there and take a look...as Shoemaker said "only once in a
millenium" none of us may see this again in our lifetimes...!
Michael Boschat
----------------------------------------
JOHN F. KENNEDY ASTRONOMICAL OBSERVATORY
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Brian_-_Day@cup: >Impact site of fragment G Tue, 19 Jul 94 00:17
Just observed a large dark spot that seems to correspond to the site of
fragment G's impact. Quite easy using an 8" newtonian from San Jose, CA
at 4:45 UT 7-20-94. Stands out much better than GRS. As it came around the
limb, it really did look like depression. *Very* impressive!
Brian Day
Peninsula Astronomical Society
brian_day@cup.portal.com
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Tom Honles: >SL-9 impacts in visible light? 19 Jul 94 17:12
In <30ehr7$qhn@search01.news.aol.com>, tomsunman@aol.com (TOM SUNMAN) writes:
>In article , cbmackay@mta.ca (C. B.
>Mackay) writes:
>
> I missed the chance to see it last night (don't ask...), so maybe someone
> can tell me: how does it look in visible light?
>
> Chris,
> I was out with my 13" Sunday night. Seeing was too bad for high
>magnification. I did not see any impact zones. I suggest everyone KEEP
>LOOKING! I tried using green & blue filters with no luck. Improving the
>contrast didn't seem to help either. JUST KEEP LOOKING! Also, don't look
>for just a a minute or two, stare at it and look carefully for as long as
>possible. Take a break now and then to rest your eyes as well. I
>understand scopes as small as 4" have seen the impact sites but you have
>to know where to look.
I was out in the backyard with the scope last night (MOnday 7-18-94 approx
from 20:00 to 23:00 PDT [ 0300 - 0600 UT ]) doing casual observations,
accompanied early in the evening by my children, and later my wife. Here
in the north area of Los Angeles (Sunland) we were able to observe through
a 20cm (8") Celestron (SCT) one of the dark 'smudges' as described here
on the net by other observers. As it was casual viewing, I did not try to
determine which impact effects we were observing. The bands were clearly
visible, 4 satellites, no red spot, and suspected comet impact appeared to
be rotating out of view.
Rather remarkable to me that we can see this event from earth, and very
remarkable that we were able to see this from light-polluted Southern
California.
******************************************************************
Tom Honles, Civil/Structural Engineer, DWP
Internet: tdh@manta.dwp.la.ca.us
or: tom.honles@f945.n102.z1.fidonet.org
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TCP/IP 2.0 on OS/2 2.1 alongside Banyan VINES & OS/2 LAN Server!
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dale.e.parson: >I'm outside RIGHT NOW looking at impact G & H(?)Jul 1994 04:56
In article mel@world.std.com (Mark E Lemire) writes:
>I just came in from viewing what are probably the same two impacts
>through a home-made 8" Newtonian at 80 and 230x. INCREDIBLE!!! I viewed
>from between 21:00 and 22:10 EDT (1:00 - 2:10 UT 7/19) and believe the
>two impact sites were from fragments G and L. L only impacted 3-4 hours
>earlier and was visible to earth for the first time and was past the
>central meridian. G was just coming center. I thought L was nearly as
>large as G! I agree -- anyone with a modest telescope should absolutely
>see this!
>
I was out in eastern Pennsylvania same time & had no problem despite the
horrible seeing, bad haze, using a C8 w 12.5 mm eyepiece (160x). Occasional
clouds blowing through obscured, but would give way a few minutes later.
Yellow filter seemed to help bring them out a bit. I had tried for B Sat.
night & saw nothing, this is the first I tried again after reading the net
Tues. (I don't watch TV). Question: I might have guessed K & L since, based
on times, K might have been the western blob out of these two. How do you know
it was G? At least it appears L was the eastern one. Under good seeing I'd
expect a 4 " scope would do the job. They appeared every bit as dark as
the southern belt, maybe a tad more so. They were a little further south than
I expected. Well worth hauling the scope out.
Dale Parson, Bell Labs, dale@aloft.att.com
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| "These words are too solid, they don't move fast enough |
| to catch the blur in the brain that flies by, and is gone..." |
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| Suzanne Vega |
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Bruce Scott TK: >I'm outside RIGHT NOW looking at impact G & H(?)ul 1994 10:44
You lucky punks! We've been socked in here for days (German weather sucks!).
Go for it, keep looking, and see all you can. You'll never forget it.
--
Gruss,
Dr Bruce Scott The deadliest bullshit is
Max-Planck-Institut fuer Plasmaphysik odorless and transparent
bds@ipp-garching.mpg.de -- W Gibson
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Dieter Kreuer: >I'm outside RIGHT NOW looking at impact G & H(?)Jul 1994 10:51
In article <30hsui$saa@search01.news.aol.com>, tomsunman@aol.com (TOM
SUNMAN) wrote:
> It's 9:01pm (059 ut) and I'm observing impacts!!!!! One is right on
> the central meridian I believe. 2 sites are easily visible at this time
> even at medium power. At 333X it's a GREAT SITE! 2 big blotches near the
> south pole.
> Anyone else see them at this time? GET OUT AND LOOK!!!!!!! You can't miss
> them. I believe they should be visible with a scope as small as 3-4
> inches.
I've watched Jupiter from 20h UT to 22h UT July 19th. At about 21h30,
a huge dark feature appeared on the SW limb of Jupiter. It looked like
(as somebody else has described it) the beginning of the umbral phase
of a lunar eclipse. Seeing degraded rapidly as Jupiter sank low to the
horizon, and it even became difficult to see the aequatorial bands, but
the dark area remained visible.
I also saw one clear and one supposed other dark spot when starting to
observe at 20h UT. These were smaller, perhaps the size of a satellite
shadow. They were at the SE edge of Jupiter and the bigger one disap-
peared behind at the limb at about 21h30, when the larger spot appeared.
Observing was done with an 8 inch f/5 Newtonian at 200x. Seeing was
miserable, most of the time.
--
----------------------- ---------------------------------
Dieter Kreuer ## ======== / dieter@informatik.rwth-aachen.de
Lehrstuhl Informatik IV __ /// /# / dieter%informatik.rwth-
RWTH Aachen ## /// # # / aachen.de@uunet.uu.net
D-52056 Aachen ## /// ##### /...!informatik.rwth-aachen.de!dieter
Germany ==== # / PHONE: +49 241 80 21413
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Mr J K A 92: SL9 & CASTLE EXPLODE!! Thu, 21 Jul 94 09:55
CAERPHILLY - WALES - UK. 52 degrees North 3 degrees West
Last night (20th July) a friend an I finally managed to get out and observe
some SL9 impact sites on Jupiter. INCREDIBLE!!. We arrived on a
mountainside just outside town at around 9.00pm local time and set up our
8 3/4" dobsonian. The sun had just set and around the horizon there lurked
an ominously murky summer evening haze. We scanned the unfamiliar skyline
for Jupiter which finally popped into naked eye view after about 10 minutes
squinting. The scope had been stood outside since I got home from work so
we could start observing almost immediately ..and what a sight. Not just one
but two huge impacts clearly visible. We knew from a very recent set of
impact time predictions that two chunks of the comet had hit 40 minutes and
10-15 minutes prior to our first look (Q2 & Q1) but we didn't really expect
such a magnificent view.
The first site had rotated well onto the disk not quite straddling the
meridian, the second had just cleared the limb of Jupiter's disk and appeared
elongated due to foreshortening. Seeing was not great but there were enough
fleeting moments of steadiness to make some drawings. We did so at about
40 minute intervals (3 drawings in all) taking abou 10 minutes over each one.
We ended up with a sequence of images spanning about an hour and a half the
second drawing shows the two spots bisected by the meridian and the third is
a mirror image of the first with the leading spot foreshortened as it starts
to leave the disk and the trailing spot sat over the meridian.
Both spots looked roughly equal in size to us and both looked larger than the
Red spot (not visible) but completely round rather than oval in shape. They
both displayed dark central areas with lighter outer areas but I'm not sure
if that wasn't an artifact of straining to see detail. In fact the impact
sites were so dark they looked ridiculously false.
At the height of our observing frenzy we suddenly became aware of a dramatic
increase in the orange light pouring into the sky from the town. We thought
at first that the murk gathering in the Caerphilly basin was reflecting the
street lighting with more than its customary venom but no. We ran to look
over the dry stone wall which was shielding us somewhat from the light
pollution and saw the town's 13th century castle (2nd largest concentric
castle in Europe ) totally engulfed in flames. What on earth was going on ??
Ah! Of course - there is a film unit at the castle at the moment shooting a
movie and this was a scene from it. I bet we were the only ones in town who
hadn't noticed the newspaper coverage of the impending spectacle. Anyway no
matter how great the explosions at the castle they were chicken feed to the
ones we were watching.
We viewed the movie fire with our binoculars for a while but were drawn
inexorably back to Jupiter. We made a final drawing and packed up as the
planet slid into the murk.
All I can say is.. ROLL ON TONIGHT !!
Jeff Alderman & Mike Austin.
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