Although it is hard to believe, summer is upon us. The summer solstice takes place officially
at 1322 on December 22nd. This is when the Sun is at its most southerly point in the sky and
therefore reaches its maximum altitude for the year at midday. Before about 130 B.C., the Sun
lay in the constellation of Capricorn at this time. The latitude on Earth at which the Sun
appears directly overhead at noon on that day, 23.5 degrees south, became known as the
Tropic of Capricorn. Due to precession, the wobble of the Earth, the solstice now takes place
when the Sun is in Sagittarius but we still call this line of latitude the Tropic of Capricorn. As
a side note, precession has also caused the dates of the so-called star signs to shift so that very
few people are actually the sign that they think they are. So much for astrology.
As we move into summer, the familiar stars of Orion the Hunter are rising in the east. Look
for the three stars that form Orion’s belt. These are known to the Maori people as Tautoru, the
beautiful carved sternpost of a mighty waka, which sails through the night sky. In New
Zealand and Australia they are also known as part of the iron pot. This is the only time of the
year when we see the pot upright. The three belt stars form the bottom of the pot. Using these
stars as a guide, follow their line to the north (left) and you will find the stars of Matariki, the
seven sisters, low on the northeastern horizon. Between Orion and Matariki, look for an
upside-down V shape. These are
the stars that form the head of
Taurus, the Bull. His horns still
lie just below the horizon in the
early December evening sky.
The warmer weather (hopefully)
in January will see Orion climb
higher to take his place as the
dominant constellation of the
summer months, bringing Taurus
with him.
Planet-wise, this is a lean time
for viewers of the so-called
“wandering stars”. Most of the
naked eye planets are visually
too close to the Sun for good
viewing. Venus is just visible in
the western twilight, very low on
the horizon. Only Saturn makes
for good viewing this summer. It
is currently rising just after 1:00
a.m., a real gem in the
constellation of Leo. If you are
not a late night person, pick up a
copy of the December issue of
National Geographic magazine.
The feature story is about Saturn
and its retinue of unusual moons.
This photo shows Saturn with the two moons Rhea and Dione, just visible below and to the
left of the ringed planet. This photo is courtesy of NASA and JPL.
Two pieces of good news have been announced since our last newsletter. The first concerns
the Hubble Space Telescope. Shuttle astronauts will make one final house call to NASA's
Hubble Space Telescope as part of a mission to extend and improve the observatory's
capabilities through 2013. Following a detailed analysis of the past three successful Hubble
repair missions NASA administrators were convinced that a safe and effective servicing
mission to Hubble was feasible. NASA Administrator Michael Griffin noted that "While there
is an inherent risk in all spaceflight activities, the desire to preserve a truly international asset
like the Hubble Space Telescope makes doing this mission the right course of action." The
flight is tentatively targeted for launch during the spring to fall of 2008. Mission planners are
working to determine the best location and vehicle in the manifest to support the needs of
Hubble while minimizing impact to International Space Station assembly. This repair mission
is fantastic news. In addition to ensuring that Hubble lasts another few years, several new
instruments will be installed. These will increase Hubble’s capabilities significantly.
The other piece of good news comes to us from the International Astronomical Union (IAU).
The IAU will be coordinating the International Year of Astronomy in 2009. This initiative is
an opportunity for the citizens of Earth to gain a deeper insight into astronomy's role in
enriching all human cultures. Moreover, it will serve as a platform for informing the public
about the latest astronomy discoveries while emphasizing the essential role of astronomy in
science education. In 1609, Galileo Galilei first turned one of his telescopes to the night sky
and made astounding discoveries that changed mankind's conception of the world forever:
mountains and craters on the Moon, a plethora of stars invisible to the naked eye and moons
around Jupiter. Astronomical observatories around the world promise to reveal how planets
and stars are formed, how galaxies assemble and evolve, and what the structure and shape of
our Universe actually are. Today, humans are in the middle of a new age of discovery, one as
profound as the one Galileo ushered in when he turned his telescope on those glorious starfilled nights 400 years ago. Astronomy, the oldest science in history, has played an important
role in most, if not all, cultures over the ages. Thanks to advanced telescopes and space
probes, astronomy continues to be a trailblazer, enhancing our knowledge by delivering
breathtaking discoveries almost on a weekly basis. The International Year of Astronomy 2009
(IYA2009) will be a global celebration of astronomy and its contributions to society and
culture, stimulating worldwide interest not only in astronomy, but also in science in
general, with a particular slant towards young people. The IYA2009 is deemed to mark the
monumental leap forward that followed Galileo's first use of the telescope for astronomical
observations, and portray astronomy as a peaceful global scientific endeavour that unites
astronomers in an international, multicultural family of scientists working together to find
answers to some of the most fundamental questions that humankind has ever asked. The
Hawkes Bay Astronomical Society and the Holt Planetarium will be actively involved in
activities designed to support IYA2009.
To close off this edition of the
newsletter, we want to wish all of our
Friends the very best during the
upcoming festive season. If you are
looking for some gift ideas, don’t forget
the Planetarium’s shop. There are 2007
New Zealand Almanacs, a plethora of
books for all ages, and great stocking
stuffers like stretchy aliens and fridge
magnets. Ho, ho, ho!
Matariki – The Pleiades