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STARGAZERS
TREATS
BOOKINGS ESSENTIAL • 07 866 5343 •
Stargazing Tours Available Most Clear Nights
Identify Constellations, Planets & Stars From Rotating Dome
Handle Meteorites Older Than The Earth
Astronomy Gift Shop
Luxury B&B With A Difference
ASTRONOMY TOURS B&B
392 STATE HWY 25 • KUAOTUNU • WHITIANGA
Photo by Peter Drury
We highly recommend a visit to Stargazers B&B and
Astronomy Tours for a ‘tour of the skies’. Alastair has
an impressive observatory and various telescopes,
including the largest one on the Coromandel, for
those who want to learn more about the heavens.
50 COROMANDEL LIFE LATE SUMMER/EASTER 2015
February and March are probably the two
most interesting months for observing
some of the treats that the southern
hemisphere skies have to offer. In the early
evening we can clearly see the three brightest
stars in the sky; Sirius the brightest, followed
by Canopus and then Alpha Centauri. Of these
three only one, Sirius, is visible to observers in
the northern hemisphere so they are perpetually
denied this celestial treat. Sirius and Canopus
are located almost directly overhead in the early
evening sky while Alpha Centauri is low in the
southeast next to the Southern Cross.
Star charts to locate these can be downloaded
each month from d they
also show locations of the various planets from
month to month.
Sirius, the brightest star, is relatively close to
us at only 8 light years away and is 20 times
brighter than the Sun. It forms the neck of Canis
Major, the big dog, which is one of Orion’s
hunting dogs. It is notable for being a double
star with a very faint companion, the Pup, which
is the first ‘white dwarf’ star to be discovered. It
orbits Sirius once every 50 years.
These weird stars are formed toward the end of
the lifecycle of stars like the Sun, and are only
about the size of the Earth, yet contain all the
mass of the Sun. Consequently their
gravity is huge and a piece
the size of a sugar cube
would weigh 5 tons! If
you stood on one (not
a good idea) and
dropped something
from shoulder
height, by the time it reached the ground it
would be travelling at 8000km/hour!
Canopus, although appearing very nearly as
bright as Sirius, is actually much further away
at 310 light years. It is a rare yellowish white
supergiant some 15,000 times more luminous
than the Sun. Canopus is very important for
interplanetary spacecraft like the New Horizons
probe currently on its way to Pluto. They carry
two main sensors for orienting themselves in
space…a Sun sensor and a Canopus sensor.
The Sun sensor automatically seeks out and
locks on the brightest thing in the sky, however
the spacecraft can still rotate around this axis
so they have a second sensor at right angles to
this which locks onto Canopus and holds them
in a stable orientation as they voyage though
the solar system. This allows them to keep their
antenna pointed directly at distant Earth so they
can communicate with us.
Alpha Centauri, the third brightest star, is the
brightest of the two pointers just below the
Southern Cross. It is notable for being the
closest star to us (apart from the Sun, of course)
and is actually a triple star
system consisting of
Alpha Centauri A,
B and C (aka
Proxima
Centauri),
a much
smaller red dwarf star.
See size comparison in
image right).
A small telescope will
clearly reveal a companion which orbits it every
90 years at about the same distance as Neptune
is from the Earth, about 4 light hours. It is about
the same brightness as the Sun and if you
could travel to Alpha Centauri and look back at
us you would see the Sun appearing as the
third brightest star!
Jupiter continues to be the brightest object in the
northeast sky. Mars and Venus will be visible very
close to each other in the early evening sky, low
in the west, late February.
On the 21st and 22nd they
will lie just to the left and
below a thin crescent Moon.
ROSETTA REPORT
The Rosetta probe
continues to send back
amazing images of Comet
67P. This one has been greatly overexposed
to show the prodigious quantities of water
and dust that are now streaming away from
the comet nucleus and will eventually form its
tail. This activity will increase dramatically as it
gets ever nearer to the Sun and heats up.
Meanwhile the Dawn space probe will go into
orbit around Ceres, our largest asteroid, on
March 6 and start its scientific mission. Over
the next 16 months it will gradually lower its
orbit around this 900km body to obtain better
and better images. It has already revealed a
mysterious large white spot on the surface and
hints of large craters.
Star maps old and new. Above, Johannes Hevelius drew
the Orion constellation in Uranographia, his celestial
catalogue in 1690. Left shows the position of Orion and
Sirius in the current sky. Download monthly star maps for
Southern Hemisphere a
Bright Stars to
Provide a Show
Look to the skies with Alastair
Brickell, astronomy buff and owner
of Stargazers B&B and Astronomy
Tours in Kuaotunu.