Sky & Telescope - July 2021 - 60

Future History

ets, cocktail glasses, cereal boxes, and just about everything
in sight. Caught up in the grip of Halley-mania, the mainstream media emphasized that the comet would be a " oncein-a-lifetime spectacle! "
Unfortunately, as Halley approached perihelion during the
fall and winter of 1985-86, its orbit kept it well away from
Earth. To make matters worse, Halley didn't start to brighten
notably until late January, when it was lost in evening twilight. Shortly after perihelion (on February 9th) when the
comet was near its brightest, it was positioned on the far
side of the Sun as seen from Earth. During March, Halley
only appeared as bright as 3rd magnitude and displayed a tail
measuring about a dozen degrees long - or a mere tenth of its
1910 splendor - for much of the month. At the same time, it
had moved below the ecliptic plane, making it difﬁcult to view
from the United States and locations farther north. Add to
that a combination of twilight, moonlight, and light pollution,
and for many people the comet was essentially a no-show.
The 1986 apparition was, in fact, decried as the comet's
worst in 2,000 years. And, as one would expect, the public
wasn't impressed. Having read he'd need binoculars and a star
map just to ﬁnd the comet, taxi driver David A. Gittelman
penned a New York Times opinion piece entitled " Who Cares
About Halley's Comet Anyway? " In it he wrote, " I was devastated. How could such an injustice be allowed to prevail? All
my life I'd been waiting - all my life. What had happened to
the cosmic leviathan of my childhood dreams? "
What happened was that at its closest approach to Earth,
on April 10th, Halley was nearly three times farther away
than at its minimum distance in 1910. And it had arrived at
this point a full two months after perihelion (instead of two

weeks, as in 1910) - long after its brightest phase had passed.
Even those living in or traveling to the Southern Hemisphere
(where the comet was well placed) didn't witness a true
showstopper. To make matters worse, Halley's tail suddenly
ebbed at the beginning of April, leaving behind a small, condensed, nebulous mass with a stubby, fan-shaped appendage.
The leviathan turned out to be a mere tadpole!

S A TAIL OF DISAPPOINTMENT Sky & Telescope Senior Contributing
Editor Dennis di Cicco captured this view of Halley on April 14, 1986 -
two nights after it shed its dust tail. Halley's tadpole-like appearance
both surprised and disappointed many observers.

S HALLEY FROM MASSACHUSETTS The photo was captured from a
beach south of Boston on the morning of March 21, 1986, and depicts
the comet's naked-eye appearance with reasonable accuracy. At the
time, Halley was making its way through southern Sagittarius (four stars
of the Teapot asterism are visible right of the comet).

J U LY 2 0 2 1 * S K Y & T E L E S C O P E

Looking Ahead

H A LLE Y AT DAWN: DENNIS DI CICCO

So, what can eager comet watchers expect from Halley's next
appearance in 2061?
A lot will depend on how the ongoing problem of light pollution worsens in the intervening 40 years. As everyone who
witnessed Comet NEOWISE can attest, even a good comet is
no match for city lights. Even if Halley performs well, the biggest challenge may simply be ﬁnding a location where you can
still see a decent number of stars.
But there are reasons to be optimistic. Reviewing the table
on the facing page, we see that the 2061 apparition is smack
in the middle of the listing, which means Halley's closest
approach to Earth will happen very near perihelion. In fact,
there were ﬁve other appearances (240 BC, 87 BC, AD 451,
AD 912, and AD 1456) when it passed closest to Earth within
10 days of perihelion. That's good news.
Indeed, the 2061 appearance is in many respects the mirror image of 1986. This time, the comet will be in full view
on the same side of the Sun as we are and should appear at
least 10 times brighter! In the morning sky, the comet will
climb to its most northern position, achieving a declination
of nearly +49° on July 24th. Then it will rapidly head south
as it enters the evening sky and will gradually favor more

Sky & Telescope - July 2021

Table of Contents for the Digital Edition of Sky & Telescope - July 2021