Bright Comet Coming - Comet Machholz (C/2004 Q2)

Starman posts -
We're long overdue for a super comet. I've been waiting a good part of a
lifetime for it. I dream about a comet whose tail extends across the
night sky for 40-degrees or more, with a nucleus that rivals Venus at
it's brightest. That comet will certainly come. It's just a matter of
time and the good luck to be alive when it does arrive.


In fact we have recently lived through (well at least some of us were around
;-} ) the most prolific period of bright comets in at least 500 and perhaps as
long as 1,000 years. Between 1957 and 1976 there were 6 "Great Comets" and
about half a dozen NEAT/LINEAR-like ones...all in the space of just twenty
years!

The past two decades have actually been historically typical for cometary
activity, with just a few fairly bright objects spread over a similar span of
time. While a new major object could in theory be just around the corner,
remember that between 1912 and 1956 there were no bright comets easily visible
from midnorthern latitudes!

JBortle

starman wrote:

Both comets were great performers, but as far as a bright spectacle is concerned, Comet West in March of 1976 is still the best one I have ever seen. Celar skies to you.


How about 'Bennett' in 1970?

It was again a good performer, but not quite as good as Comet West (1976 VI).
Bennett hit around 1st magnitude at its best, and sported a tail between 10
and 20 degrees in length. West was around magnitude -3 at its brightest and
was visible to a few observers in broad daylight. Its tail got as long a 30
degrees and that tail was brighter than even that of Comet Hale-Bopp,
possessing multiple components and a fine almost feather-like structure. I
watched West well into twilight and at least part of the tail remained visible
until around 20 minutes before sunrise. The nuclear condensation in
particular was interesting in that it was a bright yellow color in binoculars
(due to sodium emission according to one of my professors). Comet West still
stands out as the most impressive comet I have ever seen (followed by
Hale-Bopp and Hyakutake in a tie for second place). Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
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Starlord posted:

HB was bright but small, at it's best

Humm.. I wouldn't call a 30 degree tail exactly "small". The coma was at
least a degree in width and the tail was so bright that at least 10 degrees of
it was visible with the full moon in the sky. HB also stayed around a lot
longer than Hyakutake did. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

David K posts -
HB was bright but small, at it's best

Humm.. I wouldn't call a 30 degree tail exactly "small". The coma was at
least a degree in width and the tail was so bright that at least 10 degrees
of
it was visible with the full moon in the sky. HB also stayed around a lot
longer than Hyakutake did. Clear skies to you.


I have to note that a check of published observations of H-B indicate the
coma's diameter when the comet was at the peak of its display was about a
quarter degree (15') or somewhat less.

Likewise, there are very few reports of tail lengths approaching 30 degrees
(for the dust tail) for H-B. The average observer reported figures like 10-20
degrees for the main tail under good skies. I wouldn't argue that you might
have glimpsed a 30-degree tail but this was not anything like what was apparent
to most observers.

In fact, H-B's tails were unusually faint for an object with such a bright head
but perhaps not unexpectedly considering the comet's 1 AU perihelion distance.
For most of us this made the dust tail appear very weak in moonlight and I note
that at the March and April full moons, in very good skies, for me the main
tail was reduced to around 3 degrees with averted vision. This was rather
typical of what was reported at the time of these full moons by others as well.

As I indicated earlier, when a truly "classic" bright comet comes along again,
most of today's observers are going to be stunned by how spectacular such an
object can really be. Certainly a lot better than H-B was.

JBortle

from starlord:
I lived in Hawaii at the time of those two comets, and while HB was 'ok',
even at it's best it never put on the show that Hyakutake did. At it's best
( and I have photos of it ) HB was bright but small

from david:
Humm.. I wouldn't call a 30 degree tail exactly "small".
The coma was at
least a degree in width and the tail was so bright that at least 10 degrees
of it was visible with the full moon in the sky.

from jbortle:
...published observations of H-B indicate the
coma's diameter when the comet was at the peak of its display was about a
quarter degree (15') or somewhat less.
Likewise, there are very few reports of tail lengths approaching 30 degrees
(for the dust tail) for H-B. The average observer reported figures like 10-20
degrees for the main tail under good skies.

For the record, during their peaks and under the same 6.5mag. skies,
I observed HB's tail at 11-15deg., and Hyakutake's at 70-75deg.
HB's coma: 10-12'. Hyakutake's coma: at least 2.2 *degrees* ( ! )
My peak magnitudes estimates were -0.5 for HB,
and -0.8 for Hyakutake. (I must admit, though, that comparing the
condensed mags of the two was an 'apples vs.bananas' thing.)
And while HB's appearance was longer by the calendar, it's nightly perihelic
viewing window was relatively short and/or washed-out by moonlight.
I'm still glad I got to see 'em both
By the way, while I was very young during Comet West, the pictures are
spectacular. Especially the bright, fanning, aurora-like tail:
http://home.earthlink.net/~tonyhoffman/cometwest.htm
Wish I'd witnessed it Live...

SSX

OK, I was looking at a drawing I had done of the coma of Hale-Bopp and not my
old notes, as the drawing was done at a higher power than my largest field of
view for the 10 inch. I finally drug out my old notes. On March 27th, 1997
at about 0230 UT, I noted the head at about magnitude -0.7, and the size at
25' x 14' arc, with a 15 degree long plasma tail and an approximately 24
degree dust tail. I have an image I took that night does show at least a 20
degree dust tail despite a little northern skyglow (the tail went into the
Milky Way, so it was difficult to find the exact end). The inner 10 degrees
was the only part of that dust tail which had much brightness to it, although
I could see it fade into a broader and longer feature visually. Clear skies
to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************