Sky & Telescope - July 2020 - 34

Comet Commentary

When I was a young boy and ﬁrst started exploring the
night sky, the word "comet" was synonymous with "disappointment." Like so many others, I eagerly anticipated
the December 1973 appearance of Comet Kohoutek, and
the much-hyped 1986 return of the best known of them
all, Halley's Comet. Thankfully, the whole comet situation
eventually improved in spectacular fashion.
I got my ﬁrst look at Hale-Bopp on a chilly night in
August 1995 while attending the annual Mount Kobau
Star Party. This was only one month after Alan Hale and
Thomas Bopp had made their discovery. When I spotted
the comet that night on Kobau, it had shifted only 4° from
where Hale and Bopp had initially sighted it.
Here's what I wrote in my observing notebook for
August 24th: "One possibly noteworthy sight was Comet
Hale-Bopp, low in the south in Sagittarius, near Delta
Sagittarii and the globular cluster NGC 6624. The comet
was small and indistinct in my 8-inch." Even now I chuckle when I read that "possibly noteworthy" remark.
Fast forward to 1997. It's February 22nd and I'm up at 5
a.m. hoping to glimpse the rapidly brightening Hale-Bopp
from my downtown Vancouver apartment. The odds aren't
great. The comet is low in the northeast, and a full Moon
is making the city sky glow even brighter. Plus, I'm in my
living room. Luckily, it has a window facing the right direction. I opened the curtain and looked out. To my utter astonishment, there was the comet! It seemed only a touch
fainter than nearby Deneb in Cygnus. I excitedly set up
my 3.5-inch Questar telescope on the windowsill to have
a better look. The view was amazing - when I examined
the bright head of the comet, I saw what looked like a
fountain of material emanating from the nucleus itself. I'd
never seen a feature like that before - and to think I was
doing so from the living room of a downtown apartment.
Who would have dreamed such a thing possible?
That morning was the ﬁrst of many dawn encounters with Hale-Bopp. Paying a visit to the comet simply
became part of my morning routine. In my journal for
March 10th, I pondered the future. "Will this be
the best comet of my life? As I write this at
6 a.m., I can still see the comet against a
blue predawn sky. Amazing." That same
day, I was able to see it again12 hours
later in the evening sky. And though
the views of Hale-Bopp I got from a
dark-sky site a few weeks later were
unquestionably much more spectacular, it's those early morning apartment
visits that I recall most fondly. It was
enough for me to ﬁnally forgive Halley
and Kohoutek.
- Gary Seronik

J U LY 2 0 2 0 * S K Y & T E L E S C O P E

fan of dust. We knew of its
arrival months in advance,
yet West was largely ignored
by the media, a victim of
indifference so soon after the
Kohoutek debacle. Twenty
empty years elapsed before
Comet Hyakutake barreled
in on less than two months'
p THE BIG ONE Comet HaleBopp proved to be one of the
notice. An astral ghost train
most spectacular comets of the
of incredible length, it roared
20th century, in no small part
silently overhead in March
because of its unusually large
1996. Then, the following
nucleus, estimated to be as large
spring Hale-Bopp provided a
as 40 kilometers in diameter.
breathtaking encore.
A decade later, in January 2007, Comet McNaught
(C/2006 P1) blossomed into a brilliant wonder - over the
Southern Hemisphere. It showed only brieﬂy in the north.
McNaught aside, though, it was Hale-Bopp that made the biggest impact between 1970 and 2020.

Prime-Time Perfect
Right from the start, Hale-Bopp was unusual. Sporting an
absolute magnitude of -1, it was intrinsically the brightest comet to pass inside Earth's orbit since the 16th century. Early scrutiny by the Hubble Space Telescope indicated
a nucleus 10 to 40 km in diameter, and a report in this
magazine by Edwin L. Aguirre (S&T: Nov. 1995, p. 21) stated
that throughout the weeks following discovery Hale-Bopp's
"nuclear region underwent ﬂuctuations almost every night."
The activity continued, unabated, right up to perihelion.
Although the comet's telescopic appearance hadn't
improved much prior to its disappearance behind the Sun
in December 1995, it was recovered unexpectedly early on
February 1, 1996, at which point its brightness had improved
to magnitude 8.8 - better than anticipated. Throughout
the summer and fall of 1996, the comet grew steadily, albeit
rather slowly. Veteran comet watchers cautioned that a blockbuster show wasn't guaranteed. As Hale-Bopp headed
down the homestretch in early 1997, the question
on everyone's mind was, will we be dazzled or
disappointed?
We needn't have worried. Even though
Hale-Bopp came no nearer to Earth
than 1.3 a.u. (ten times the distance of
Hyakutake), it beneﬁted from impressive physical properties (bigger and
more dust-rich than Hyakutake) plus
a delightful conﬂuence of timing and
t DAWN VISITOR Gary Seronik made this pencil sketch of Comet Hale-Bopp on the morning of
March 14, 1997, from the window of his apartment in downtown Vancouver, British Columbia. He
recorded the "shells" surrounding the comet's pseudonucleus using his 3.5-inch Questar telescope.

SE AN WA LK ER

A Comet for City Dwellers

Sky & Telescope - July 2020

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