Sky and Telescope - January 2016 - 48

OBSERVING

Celestial Calendar

Quads to Come Out of Hiding
The least-observed major meteor shower should be in plain sight this year.
Will this be the January you add another
major meteor shower to your life list? If
the Quadrantids have eluded you up to
now, you're not alone.
Maybe you've read that they're one
of the richest annual showers, with
peak rates variously quoted as 60 to 200

Brian Emﬁnger of Arkansas caught an early
Quadrantid ﬁreball on the morning of January
3, 2012. Unlike most meteors, it began close
to the radiant - meaning it ﬂew nearly toward
the camera, moving very far through the
atmosphere before ending in a terminal burst.
The Big Dipper is above it. A shower's radiant
is the perspective point where all its meteors
would appear to come from if you could see
them long before they hit Earth's atmosphere.

visible per hour under ideal conditions.
And maybe you've gone out and been
skunked. Their maximum lasts just a
few hours, and if it doesn't fall between
midnight and dawn for your part of the
world, you miss it.
This year North Americans should be
in luck. The International Meteor Organization (IMO) predicts that the shower's
peak will be centered around 8h Universal
Time January 4th (3 a.m. that morning
Eastern Standard Time; midnight January 3-4 PST). That prediction is based
on a few well-observed showers since
1992. But a model by Jérémie Vaubaillon predicts a Quadrantid peak about 8
hours earlier, which would be optimal for
observers in Europe.
Complicating things, mass sorting in
the meteoroid stream means that faint
meteors are their most abundant before
the visual peak, and bright ones after.
The Moon will be a thick waning crescent on the morning of Monday the 4th.
It will rise around 2 a.m. local time but
shouldn't pose any great problem.
The Quads are under-studied by
amateur meteor counters, especially
in the hours and days away from the
peak, no doubt because of the late-night
January cold. (Only in northern latitudes
does the shower's radiant rise high.) So
think adventure. To keep warm, snugify
in many layers from head to feet with no
pinches or thin spots. An electric hot pad
buttoned inside your clothes will help.
The shower's radiant is in the obsolete constellation Quadrans Muralis (the
mural quadrant), oﬀ the handle of the Big
Dipper between the head of Boötes and
the arched back of Draco. It's reasonably
well up in the northeast after about 1 a.m.

d Meteor Shower
4 Quadrantid Meteor Shower
1 am, Jan 4

Little
Dipper

DRACO

Big
Dipper

Radiant B O Ö T E S

Arcturus

Looking Northeast
Not until early morning does the Quadrantid
radiant start to rise high. (And don't expect to
see several meteors at once!)

local time and climbs higher until dawn.
The higher a shower's radiant, the more
meteors appear all over the sky.
You can join amateurs doing scientiﬁc
meteor counts for the IMO if you have at
least a moderately dark sky and an hour
or more to commit. You'll need to follow
the standardized method, which includes
determining your faintest naked-eye stars
in the part of the sky you're watching.
Your latitude and longitude, the time
every half hour or so, any minor obstructions by clouds or trees, and time spent
looking away also need to be recorded so
the IMO can correct your observed rate
to the standardized zenithal hourly rate.
This way, observers' counts from around
the world can be compared to track what
the shower does throughout its duration
- if enough people participate! For the
instructions and how to report, see imo.
net/visual/major.

FOLLOW THE SHOWER ONLINE As Quadrantid observers report their counts to the International Meteor Organization, you can watch
this year's activity curve develop hour by hour on the homepage of imo.net.

Januar y 2016 sky & telescope

http://www.imo.net/visual/major http://www.imo.net/visual/major http://www.imo.net

Sky and Telescope - January 2016

Table of Contents for the Digital Edition of Sky and Telescope - January 2016