Sky & Telescope - April 2023 - 45

Evenings with the Stars by Fred Schaaf
Corvus and
Company
This little constellation
can guide you to spring
sky delights.
T
his month let's look at the many
marvelous and helpful connections
that Corvus, the Crow, has with other
constellations. In last May's column,
I focused on the stars outlining the
rhombus or sail shape of Corvus. That
pattern reaches its highest point in the
sky around midnight in April and on May
evenings. So, there's plenty of time for
the Crow to guide us to springtime sights.
Let's begin with Corvus's relation to
one of the sky's brightest stars, 1stmagnitude
Spica, in Virgo. The star is
only about 10° from Corvus, so it provides
a handy point of reference. Those
learning their way around the sky for
the first time might be unsure exactly
which stars make up the celestial crow
- especially considering that a portion
of the nearby (but much dimmer)
grouping, Crater, has roughly the same
shape. However, Spica's proximity to
Corvus quickly clears up any possible
confusion about which is which.
Far less obvious than its connection
with Spica are those between Corvus
and several other constellations. For
instance, the main pattern of Corvus
is centered on -20° declination and
neatly contained between the 12h and
13h lines of right ascension. Interestingly,
Crux, the famed Southern
Cross, is exactly 40° due south, lying
between those same right ascension
lines. Of course, Crux is so far south
that it barely peeks above the horizon
in the U.S. even from locations such as
southern Florida and Texas. From these
places, however, Corvus climbs roughly
halfway to the zenith (the point in the
sky directly overhead) and serves as
a guide to locating the haze-dimmed
pCELESTIAL CROW Corvus, the Crow, keeps close company with Crater (the Cup) and Hydra
(the Water Snake) but has connections to many other constellations north and south.
Southern Cross as it scrapes along the
horizon. The connection between Corvus
and the Southern Cross also comes
in handy if you're planning a stargazing
trip to the Southern Hemisphere.
Many of the sky's most sought-after
treasures lie in the vicinity of Crux, so
if you want to take in that spectacular
stretch of the southern Milky Way,
just remember to choose a time of year
when Corvus is well placed for viewing
at some point during the night.
North from Corvus, we find several
more stops of interest. The Autumnal
Equinox point (where the Sun is
positioned at the start of autumn) is
about 20° above (and slightly right) of
Corvus. Proceeding directly north from
the Crow, we traverse the telescopic
wonderland of the Virgo Galaxy Cluster
(see page 20) before reaching the lovely,
Coma Star Cluster. Finally, turning to
face north, we see the Big Dipper centered
70° to 80° due north of Corvus.
Returning to the faint constellations
closer to Corvus, we have the aforementioned
Crater, the Cup. Both the Crow
and Cup are imagined perched on the
back half of Hydra, the Water Snake. If
you turn to our April evening star chart
(pages 42 and 43), you'll see Hydra
slithering across the meridian, but it's
so long that the end of its tail has yet
to rise in the southeast. The brightest
Hydra star nearest Corvus is 3rd-magnitude
Gamma (γ) Hydrae. It shines at
essentially the same brightness as Delta
(δ) and Epsilon (ε) Corvi, which mark
the constellation's northeast and southwest
corners, respectively.
Corvus and Crater are not only
side-by-side in the sky, but they're also
connected in story. In one Greek myth,
Apollo punished the crow for lying
about why the bird took so long to bring
the god the bowl of fresh water he had
requested. Corvus claimed that a snake
had blocked access to the water source,
when in fact the crow had been busy
enjoying fresh figs. Apollo saw through
the lie and condemned the bird to a
life of thirst, which explains the crow's
raspy voice. When it died, Apollo put
Corvus in the sky with the bowl (Crater)
and the snake (Hydra).
An Aesop fable has a more pleasant
connection between Corvus and
Crater. In this tale, a thirsty crow placed
pebbles in a cup to raise the water level
until it was high enough for the clever
bird to finally have a satisfying sip.
¢ FRED SCHAAF remembers watching
the tail of Halley's Comet brightening
and lengthening as it spread across
Corvus in April 1986.
sk yand tele scope .o r g * APRIL 2023 45
JOHANN BAYER / IOANNIS BAYERI RHAINANI VRANOMETRIA /
POLONA DIGITAL LIBRARY / PUBLIC DOMAIN
https://skyandtelescope.org/
Sky & Telescope - April 2023

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