Comets And Aurora!

Just in from a great evening session from 21.30 - 23.00. Sky was very murky and trans poor (5 - 6). using John Mc Connells 8.5" Donsonian with 40mm eyepiece i successfully tracked down 73P/ Schwassmann - Wachmann 3 fragment C and my first observation of fragment B!! I was able to quickly slew the scope to both objects for comparison and i have to say just how much brighter B was in relation to C (main Body) with a brillant stellar false nucleus and tiny 1-2' coma even in the dense murk. I will re observe these two before dawn when they are better placed in the hope of making some tail observations. Also had a look at M31, M32, M94, M13, M92, M34, M44, Saturn, Berenices Hair Clip, Garnet star, Polaris, Delta Cephei.

At 21.30 in bright twilight i may have seen several vertical rays from a possible aurora display however was unable to confirm anything. Later i got a text from Conor who had just captured a green and red aurora on an image!..well done Conor. I hope it turned out well.

Great session!

Martin - dunno if this interests you...


More 120-second second exposures of the 73P complex, taken with the
Mt. Lemmon 1.5m telescope in good seeing, have revealed new fragments
and some changes in the known fragments. Al Grauer (A. D. Grauer)
was observing with me last night, and I performed all the measurements.

Below are quick summaries of some of the brighter/more interesting
fragments. Since I count approximately 40 fragments (with more surely to
be found in the future), I'm not going to speak to every single fragment.
Most of the faint fragments display a 6"-10" coma with no tail, unless
otherwise noted. Magnitudes are total integrated magnitudes, and
morphology descriptions were based on the 4 coadded 120-s exposures. All
references to our temporary designations in the text below will have an
implicit "6GA" preceding the 4-digit hex number.

I have suggested links to previously-designated fragments where I have
reasonable confidence.



I detected 4 fragments leading component C (ESE from C):

F4D3: threshhold object, confirmation necessary.
F4D1: diffuse 6" coma, no tail
F4D4: slightly condensed 10" coma, no tail
F4D2: moderately condensed 15" coma, elongated toward PA 230

No astrometry of fragment B, as its coma in all my images was saturated (I
took short exposures of C, in addition to the 120-s exposures, for
reference astrometry. Should have done the same with .

Fragments between B and C:

F4D5: diffuse 6" coma elongated toward 230. Located approx. 1870" in
PA 300 from component C.
F4D6: (Q): diffuse 6" coma, no tail.
F4D7: (P): moderately condensed 8" coma, 10" tail toward 230

No fragments detected between B and G.

Fragment G:

F4D8: (G)
F4D9: secondary condensation within the tail of G. See previous report
"comet 73P-G split?"

Fragments G onward:

F4DA
F4DB (R): Dramatically brighter than on March 25. Fairly round,
well-condensed 45" coma, elongated toward 230.

F4DC (K/S): This is a fairly unresolvable mass measuring approximately 15"
x 10", long axis is roughly E-W. There are possibly 2 condensations, but
this is definitely at the noise level, so I'm reporting what I consider to
be the brightest portion of the condensation. The secondary condensation
would be located roughly 6"-8" toward PA 70, but again, I stress that this
is at the noise level.

F4DD (M): well-condensed 12" coma, 20" tail in PA 230

F4DE (N): well-condensed 30" coma, extended ~45" to 230. Also
considerably brighter than on March 25.

F4DF: 10" coma, 15" tail PA 230
F4E0
F4E1: moderately condensed 20" coma, elongated toward 230
F4E2
F4E3
F4E4: 10" coma, elongated toward 230
F4E5
F4E6
F4E7: slightly condensed 10" coma, no tail
F4E8=F4E0
F4E9: condensed 10" coma, 15" tail toward 230
F4EA: moderately condensed 12" coma, no tail
F4EB
F4EC
F4ED
F4EE: diffuse 10" coma, 15" tail toward 230
F4EF
F4F0: moderately condensed 15" coma, elongated ~20" toward 230

F4F1: this fragment struck me as unusual due to the apparent lack of
activity. Object appears stellar and is approximately V=19.7; I think
this corresponds to an H value of approximately 20-21, depending on albedo
and if it is indeed truly inactive. I followed it up twice more, also
with 120-second exposures, and it still appeared stellar. This fragment
definitely deserves careful monitoring. If it remains inactive it could
provide great opportunities for physical characterization as (or if) it
gets brighter.

F4F2
F4F3
F4F4: condensed 12" coma, elongated ~20" toward 230
F4F5
F4F6
F4F7

I searched an additional 1.5 degrees along the line of variation beyond of
the westernmost fragment F4F7 and found nothing down to 22nd magnitude.
On the eastern side of the complex, I only searched approximately 3
arcminutes beyond the first reported fragment, F4D3 (~1.4 degrees in front
of C). The fragments leading C were honestly a surprise; I'll make sure
to image at least another degree ahead of F4D3 next time.

Dave thanks alot..that does interest me alot...40 fragments and counting!!

Heres a CCD image of C and B taken tonight by a member of the MPML..