The Goat Star
- The Goat Star: A Strange Light in the Northeast
By Joe Rao
SPACE.com's Night Sky Columnist, SPACE.com
Recently I received an interesting inquiry from Professor Rob
Eisenson, Assistant Professor in the Dept. of Physics, Astronomy, and
Meteorology at Western Connecticut State University.
"In recent SPACE.com columns you have been advising people to look
for Mars low in the southeast sky after nightfall," Eisenson
writes. "Yet, I have also been seeing another unusually bright star-
like object, but low in the north-northeast sky soon after it gets
fully dark. It isnt so much that it is bright, it is just that I dont
recall ever seeing such a bright star located so far to the north. It
also sometimes seems to twinkle with the same kind of yellowish-
orange light that Mars shows now. Can you identify what I am seeing?"
What Professor Eisenson was looking at is indeed a brilliant star
with a distinct yellowish hue. In fact, its the sixth brightest in
the sky (magnitude 0.08) and as seen from mid-northern latitudes,
ranks number four behind Sirius, Arcturus and Vega.
It is Capella, in the constellation of Auriga, the Charioteer.
Auriga is one of those star patterns whose exact origin is a hopeless
mix of antique conceptions. The Greek and Roman legends made Auriga a
famed trainer of horses and the inventor of the four-horse chariot.
But the most ancient legends also had Auriga as a goatherd and a
patron of shepherds. The brilliant golden-yellow Capella was known as
the "Goat Star," with a nearby triangle of fainter stars representing
The confusion in concepts is reflected in the ancient allegorical
pictures and star names. Auriga is usually represented holding a whip
in one hand in deference to the Charioteer story, but in his other
arm he is holding a she-goat (Capella) and her three kids.
In his classic guidebook, "The Stars, A New Way to See Them"
(Houghton Mifflin Company, Boston), Hans A. Rey (1898-1977) drew
Auriga looking like a man with a tough expression, a jutting chin and
a pug nose, " . . . as befits the driver of a war cart."
Capella measures 16 times as large in diameter as our Sun, 174 times
as luminous, and is located 42 light-years away. It is part of a
multiple star system, interestingly containing at least four stellar
As was noticed by Professor Eisenson, Capella appears to rise well to
the north of due east. In fact, it is the nearest to the North Pole
of the sky of all the first-magnitude stars, and across much of the
48-contiguous United States it is visible at some hour of the night
throughout the year.
From western Connecticut, for example, Capella is below the horizon
for only about 3 hours out of a 24-hour day. Lying 46 degrees north
of the celestial equator, Capella can pass directly overhead for
anyone living at that latitude north of the terrestrial Equator (say,
Houlton, Maine or Geneva, Switzerland). And for anyone at points
north of latitude 44 degrees (for example, Minneapolis, Minnesota or
Bologna, Italy), Capella will appear to graze the northern horizon,
but will not go below it.
Interestingly, the brilliant blue-white star Vega is only a trifle
brighter and lies almost diametrically opposite in the sky from
Capella and at about 39-degrees from the celestial equator, affords a
similar rising reference for northern sky watchers in the early
In the table below, we have prepared the rise times for Capella for
three dates this week (Sept. 19, 22 and 25) as seen from 10 different
latitudes, each separated by 2-degree increments. Also provided for
each latitude is the azimuth the direction on the horizon where
Capella will first appear. As already noted, from latitude 44 degrees
and all points north, Capella is always above the horizon.
All times are given in civil or local daylight time (LDT), which
differs from ordinary clock time by many minutes at most locations.
Most civil time zones worldwide have been standardized on particular
longitudes at increments of 15. As an example, across Europe, 0 (the
Greenwich Meridian); 15 east; 30 east, etc. Across North America,
there is 60 west (Atlantic Time), 75 west (Eastern Time), 90 west
(Central Time), etc. If your longitude is very close to one of the
standard meridians, luck is with you and your correction is zero.
To get local standard time, add four minutes to the times listed for
each degree of longitude that you are west of your time zone
meridian. Or subtract four minutes for each degree you are east of it.
Your clinched fist, held at arms length will measure roughly 10
degrees. So 20 degrees would measure roughly "two fists" when making
an estimate of azimuth.
EXAMPLE: From Durham, North Carolina, on September 22, when and where
will Capella appear to rise? Durham is located near latitude 36 north
and longitude 79 west. Looking at the column under September 22, we
see a rise time of 8:51 p.m. for latitude 36. But since Durham is
located 4 west of the Standard meridian, we must add 16 minutes to
8:51 p.m. So Capella will actually rise at 9:07 p.m. From the
latitude of Durham, Capella will appear to rise 27 degrees east of
due north, or less than "three fists" to the east (right) of due
For other dates and latitudes, you can interpolate.