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Pickering
Scale
P-1 Star image is usually about twice the diameter of
the third diffraction ring (if the ring could be seen).
P-2 Image occasionally twice the diameter of the third
ring.
P-3 Image about the same diameter as the third ring and
brighter at the
center.
P-4 The central disk often visible; arcs of diffraction
rings sometimes seen.
P-5 Disk always visible; arcs frequently seen.
P-6 Disk always visible; short arcs constantly seen.
P-7 Disk sometimes sharply defined; rings seen as long
arcs or complete circles.
P-8 Disk always sharply defined; rings as long arcs or
complete but in
motion.
P-9 Inner ring stationary. Outer rings momentarily stationary.
P-10 Complete diffraction pattern is stationary.
Instruments and locations: 13" f/4.5 split ring
eq. with coulter pyrex mirror refigured by John Hall used in my driveway
in the west end of Washington
Missouri, about N 38.5, W 91, the tube assembly is cooled outside by exhaust
fan for 2 hours before observing
30" f/4 dob. at Colter-Menke Observatory 4 miles west of New Haven, Missouri,
about N 38.6, W 91.2
7-19-99 4 to 5 am, slightly foggy, no jet, ave. upper atmos. moisture. Seeing about p5. Best view with 5x7 oval on 13". Not much detail seen.
7-22-99 3:30 to 5:15 at Colter-Menke, 6" f/20,
no fog, slight jet, ave. upper atmos. moisture. Seeing p6.
GRS easily visible, not too red, some barges
visible in neb, small black spot seen in moments of better seeing slightly
preceding and just south of the grs.
7-25-99 4 to 5 am, no fog, slight jet, very
low upper atmos. moisture. Seeing not measured, est. p4/p5.
Best view with 5x7 oval with the 13" . Little
detail seen, some white spots or gaps were visible on the s border of the
neb. Used binoviewer for the 1st time. Gave good views at ~225x,
almost acceptable views at ~900x. Saturn held up pretty well
at this high power.
7-26-99 4 to 5 am, no fog, no dew, ave. upper
atmos. moisture, seeing about p4 (not measured note added
8-29-99), best view with 5x7 oval with the
13" at 220x, little detail seen, large, very dark festoon going from neb
to center of tz and back, on the central meridian.
7-29-99 3:45 to 5:15 am, no fog, no
dew, high upper atmos. moisture, 40 mph jet, seeing measured at p6,
best view with 13" at full aperture at 220x,
good amount of detail seen including the spot seen 7-22-99. This
spot is blue circle WS in the STBs according to
http://unicorn.kk-system.co.jp/Alpo/Program/JupRot/JupRot.htm.
(The spot is STB DS #6 according to Alpo alert July 27, 1999: http://www.lpl.arizona.edu/~rhill/alpo/jupstuff/jupalert.html
note added
8-24-99)
7-30-99 3:15 to 4:15 am, no fog, no dew,
ave. upper atmos. moisture, no jet, seeing measured at p4/p5, best view
with 13" and 5x7 oval using my new 5
mm U.O. abbe ortho (300x), little detail seen other than the large festoon
mentioned 7-26.
8-3-99 3:30 to 4:30 am, no fog, no dew,
partly cloudy, edge of the jet, seeing p4, best view with 13" and 5x7 oval
using 5 mm ortho at 300x, little detail
seen other than the end of the transit of Io.
8-11-99 3:30 to 4:00 am, no fog or dew,
clear, edge of jet overhead, seeing p4, best view with 13" and 5x7 oval
using 5 mm ortho, little detail seen
except end of transit of Ganymede.
8-12-99 3:45 to 4:00 am, no fog or dew, edge of jet overhead, seeing p3, best view ?, there was none from Washington.
8-16-99 4:00 to 5:00 am, no fog, moderate
dew, no jet, clear, winds from the north, seeing p6, best view with 13"
at full aperture with 5 mm ortho.
Plenty of detail visible but too tired to concentrate on it. Appeared
to be some activity in the ntz.
8-18-99 3:30 edge of jet, slight fog, seeing p6, but not much detail with 13" at full aperture though
8-20-99 3:30 moderate dew, moderate jet, seeing p4 with vary rare p6, wind from the north, 30" f/4 stopped down to 12" f/10. grs and hint of STB DS #6
8-26-99 3:30 to 6:00 am, moderate to moderately
heavy fog, jet stream 45 mph, no clouds, moderate upper level moisture,
trace wind from the north,
temperature 64, dew point 64, seeing p7 much of the time, best view with
13" at full aperture at 300x with 5 mm ortho. Saw end of transit
of Io
starting when it was still .25 Jupiter diameters from edge. It was
just barely within the south edge of the SEB. NTBn DC #2 or possibly
#1, but
not both, seen during moments of good seeing when it had rotated .25 Jupiter
diameters onto the visible disc. A great deal of detail also seen
in
the NEB, TZ, and SEB.
(observed about L2 285 so couldn't have been either DC #1 or #2
note added 8-28-99)
8-28-99 3:30 to 4:45 am, very slight fog,
24 mph up. level winds from the n, no clouds, mod. upper level moisture,
trace wind from south, temp. 66,
dew point 66, seeing p7 much of the time best view at 13" at full aperture
and 300x with 5 mm ortho, observed L2 215, spot north of NTBn seen
as on 8-26-99, also appeared to be 4 spots seen very close together
with a slightly larger gap between the center two in NNTB at same
longitude as the spot n of the NTBn.
8-29-99 3:30 to 6:00 am, slight fog, 20 mph
up. level winds from the n, no clouds, mod. up. level moisture, 2 mph wind
from the ne, temp. 66, dew point
66, seeing p6, best view of Jupiter this year or last even though the seeing
was not the best!?. Used 5 x 7 oval on 13" oriented horizontally
rather than vertically. We tried it both ways and the difference
was amazing! We rotated the tube 90 degrees and tried it again, same
fantastic
results! The horizontal orientation made all the difference.
It was much better than a 5" circle which gives the same view no matter
where it is
placed or how the tube is oriented.
9-1-99 3:30 to 4:30 am,
no fog, no dew, 30 mph up. level winds from the nw, partly cloudy, wind
calm, temp. about 60, dew point mid 50's, seeing
p4 with a few moments of p6. Best view with 5x10 oval on 13" at 300x
with 5 mm ortho. Session started with grs on the meridian, dark spot
# 6 visible now and then, rift not visible in seb.
9-2-99 3:30 to 5:00 am, trace
fog, moderate dew, 20 mph up. level winds from the n-nw, winds light from
the se, cloudy much of the time, dew point
66, temp 70, best view with full aperture at beginning of session when
seeing was excellent. I did not get a chance to measure the seeing
or
notice any detail on the planet before the clouds came in the 1st time.
When they cleared up briefly 30 min later the seeing was terrible even
with the aperture mask.
9-4-99 3:30 to 6:00 am, slight haze,
light dew, 28 mph up. level winds from the n-nw, surface winds from the
east at 5, temp 65, dew point 65, no
clouds, moderate up. level moisture, seeing p6 much of the time with
occasional very brief seeing of p7. Used full aperture and 5x10 horizontal
oval on the 13", about the same view with each when the seeing was at it's
best but the view was consistently better with the aperture stop
most of the time. I am beginning to think I would need constant p8
seeing, with occasional p9, to begin to make use of the full 13" aperture.
A 7"
or 8" objective is probably all that is needed to take full advantage of
p7, which is as good as I've ever seen here with one or two possible
exceptions. Observed the spot first seen 8/26, then again 8/28.
This time it appeared slightly elongated, similar to NTBn DC #1.
It was on the
meridian about 5 am CDT which puts it at about 211 degrees system 2.
At the end of this observing session we turned the scope to the
trapezium and were able to hold the f component with direct vision during
moments of better seeing at full aperture.
9-9-99 4:00 am, clear, no dew, 30mph upper
level winds from the nw, surface winds from the n at 4, temp 54, dew point
49, no
clouds, low upper level moisture, seeing p3 and often p5 but little detail
visible.
9-14-99 Here is my first attempt at
drawing Jupiter. I believe the CM at 3:48 was about 231 degrees system
2. The upper level
winds were 60 mph out of the west, surface winds were out of the west at
2, temp was 46 and dew point was 42, upper level moisture was moderate,
light dew, no fog, no clouds, best view with full aperture (13") and 300x
with 5mm abbe ortho even though seeing was 4 and sometimes 5 with the
pickering scale. Even though the seeing was measured as poor it looked
good on jupiter and the f component was seen in the trapezium at full aperture,
and seen better than on 9/4 even though the seeing that night was p7 at
times!? The condensations seen in the NNTBn were also seen 8/28?
If so they
have moved. I did not get the best look at them since they were well
past the CM when I saw them. But they were dark and obvious at times,
darker
than the condensation in the NTBn at about 212 degrees system 2.
9-18-99 3 am, light dew, wind from ne at 2, up.
level winds from east at 50, temp 50, dew point, 48, some thin high clouds
seeing p3,4,
poor view even with aperture stop, could not even see STB DS #6, cm was
82 degrees system 2.
9-22-99 4:30 am, moderate dew, wind from the
nw at 2, up. level winds from n at 55, temp 40, dew point 40, clear, high
up. level moisture, seeing p4, poor view,
could just make out STB DS #6 on the cm at times with 5" aperture stop
at 300x.
9-23-99 3:30 am, moderate dew, wind from the sw
at 2, up. level winds from nw at 36, temp 46, dew point 44, clear, mod.
up. level moisture, seeing p5, poor
view at full aperture, best view at 220x and 5" round aperture mask, finally
got to see glimpses of the NEB rift but little other detail was visible.
9-26-99 5:00 am, no dew, wind from the sw
at 6, up. level winds from n at 20, temp 64, dew point 49, clear, mod.
up. level moisture, seeing p4, best view with 5"
aperture mask at 220x, very little detail visible
9-30-99 4:30 am, moderate dew, fog in low
lying areas wind from the w at 1, up. level winds from w at 55, temp 40,
dew point 38, clear, mod. up. level moisture,
seeing not measured but subjectively very good, used 40" f/5 stopped down
to 17" f/11.75 at New Haven for very good views of Jupiter, saw 8 or 9
stars
in and around the trapezium at full aperture!
10-1-99 3:30 am, moderate dew, no fog, wind
from the sw at 6, up. level winds from w at 60, temp 45, dew point 40,
clear, mod. up. level moisture,
seeing p3 with occasional p4, used 13" stopped down to 5"x7" horizontal
oval for best image, but no detail visible outside of equitorial belts.
10-5-99 3:00 am, very heavy dew turning to
frost, trace fog developing into very heavy fog, surface wind calm, up.
level winds from the w at 55, temp 35, dew
point 35, no clouds, low up. level moisture, seeing subjectively very good,
no 5" aperture mask available for the 40" yet, best view at 500x with 17"
f/11.75,
a great deal of low contrast features visible such as white ovals in the
south of the STB at about 139 degrees system 2, when the fog moved in from
the
north west the seeing actually got slightly worse, this may be due to the
layer of frost we noticed on the secondary when we were closing up the
observatory for the night!
10-7-99 4:00 am no fog, trace dew, light
surface wind out of the se, upper level winds about 60 mph from the NW,
temp about 50, dew point about 40. No clouds
up level moisture was moderate, Seeing not measured but estimated as p4/p5
with the 40" stopped down to 17" f/11.75 at 385x. Little detail visible outside equ.
belts
10-27-99 4:00 am, no fog, no dew, light or no surface wind out of the south
upper level winds about 45 mph out of the nnw, temp 45, dew point 39, no clouds, moderate
upper level moisture, back side of a high pressure ridge, seeing measured at p2/p3. no detail visible on Jupiter
other than the cloud bands. However the e and f
components were seen in the trapezium.
