Stargazer: Water, water everywhere! Nor yet a drop to drink!

September sees the start of the new season of meetings of the Torbay Astronomical Society at Torquay Boys Grammar School. This season, we kicked off with a visit from a speaker who has provided observations to a number of Pro-Am collaborative projects.
The recent successful landing on the Moon by the Indian Chandrayaan probe is the latest in the search for water on the moon. This water is believed to be contained in ice sheltered in the deeper, darker craters at the lunar poles, particularly the South Pole. This search has been going on for some 70 years ever since researchers at Caltech in the USA suggested that deep, shadow-filled craters may contain ice in 1961. Trace amounts of water were found in some rock samples brought back from the Moon by Apollo astronauts, but these were put down to the almost inevitable contamination on the journey to Earth.
Soviet scientists working with samples returned by the Luna 24 probe in 1976 claimed that they had definitively found water at about 0.1% by mass (10 times the expected value but still minuscule).
In 1994, the U.S. Military probe “Clementine” orbited the poles of the Moon with some of the most sophisticated camera and detection equipment available at the time. It revealed radio echoes consistent with an icy, rather than a rocky surface in certain areas of the Moon’s South Pole. However, these results were inconclusive and have been discredited.
The Lunar Prospector probe launched in 1998 examined both Lunar poles for concentrations of Hydrogen (one of the constituent elements of water) and found it abundant to 50 parts per million, but this could equally be due to the Hydroxyl radical (OH) which is chemically bound to other atoms to form the rocky compounds in the Lunar surface. Based on these observations NASA scientists calculated that, if water is present, it could amount to 1-3 cubic kilometres. At the end of its mission Lunar Prospector was deliberately crashed into the Shoemaker Crater at the Lunar South Pole in the hope that detectable quantities of water would be liberated. Earth based observers detected no water at all.
NASA’s Cassini-Huygens and Deep Impact missions made fly-by studies of the Lunar poles on their way to Saturn and Comet Tempel-Tuttle respectively, but only succeeded in producing more conflicting and confusing results.
Japan’s Kaguya lunar mapping probe failed to detect any water on the Moon but made the first detailed optical observations of the permanently shadowed Shackleton crater, a favourite site for the possible Lunar ice to exist. China’s Chang’e took the first detailed photographs of these areas of the Moon. Both of these missions took place in 2007.
In 2008, India’s Chandrayaan 1 detected water in the thin atmosphere above the Lunar South Pole in 650 mass spectra readings. This thin atmosphere had first been detected by Kaguya which showed that it was created when Oxygen from the Earth’s atmosphere was transported to the Moon via magnetospheric ions (ions travelling along magnetic field lines between the Earth and the Moon).
The Pragyan Rover aboard the Chandrayaan mission will look for further evidence of water during the month that it is expected to operate on the Moon. There is still a long way to go to confirm the existence of readily available water at the Lunar poles. The importance of these explorations is paramount, as water on the Moon would mean that gallons of the life-preserving liquid would not have to be carried aboard manned spacecraft destined for the Moon and the possibility of maintaining a permanent Lunar Base would become more realistic.
September also begins a new round of outreach sessions. At the moment the diary is mostly free. Anyone who is interested in booking an outreach session for their group, school or club should contact me, John Stapleton at torbayastrochairperson@gmail.com with the word “outreach” in the subject bar.
by John Stapleton, Chairman, Torbay Astronomical Society

Skynotes
Please note all times given in this article are in GMT so remember to add an hour to get the time in BST.
Sun: From the beginning to the end of the month the period of dark sky increases from 6.5 to 8.5 hours. The Autumnal Equinox, when night and day are of equal length, occurs on 23rd. The longer period of darkness provides a good opportunity to view the summer constellations and the Milky Way that runs through them. The Milky Way is actually our view through the spiral arms of our Galaxy which we see as a faint band of light caused by millions of distant stars.
Mercury: Mercury is an early morning object reaching its greatest Western elongation (farthest distance from the Sun as seen in the sky on 22nd). It is located against the background stars of Leo but is not well placed for observation.
Venus: Venus is also a morning object seen against the background stars of Cancer. It is visible throughout the month and is an unmistakeable brilliant object in the pre-dawn sky. If you are able to track the planet’s position it is even visible through binoculars or a small telescope in broad daylight.
Mars: Mars is not visible this month.
Jupiter: The largest planet is visible in the Eastern sky throughout the month. It can be seen below the stars of Aries and above the tail of Cetus the Whale. The coloured bands and zones on the surface of the planet can be distinguished with small telescopes as can the Great Red Spot, a colossal hurricane, greater in diameter than the planet Earth. The Galilean moons can be seen with a good pair of binoculars or a small (bird-spotting) telescope. DSLR images of the planet will also pick up the moons.
Saturn: The ringed planet can be found further South, against the stars of Aquarius, and is also visible throughout the month. Saturn is fainter and lower in the sky than Jupiter but is still easily visible. The rings are beginning to open out, from our point of view and are consequently becoming brighter. Saturn’s largest moon, Titan, can be seen above and to the right of the planet with a good pair of binoculars or a small telescope.
Uranus and Neptune: Uranus is not visible this month. Neptune reaches opposition (due South in the sky and at its highest elevation) on 19th. The blue planet can be found beneath the “Circlet” asterism which marks one of the fishes of Pisces, a little closer to Saturn than Jupiter. At magnitude 7.8 it will require large binoculars or a small telescope to find it. Neptune displays a smaller and truly blue disc compared to that of Uranus although it will appear only as a bluish star to most small instruments.
Meteor Shower: There are no bright meteor showers due in September, but it is still possible to see sporadic meteors not belonging to any shower.
Comet: There are no bright comets expected this month.
The Third Quarter Moon occurs on September 6th with New Moon on 15th, First Quarter then follows on 22nd September and Full Moon on 29th. This Full Moon is also known as the Harvest Moon for the wheat harvest more common in Europe than last month’s corn harvest.
Diary Dates
The next meetings of the Torbay Astronomical Society will be held at Torquay Boys Grammar School. Talks, this year, will be held in The Forum Lecture Theatre at the front of the school, unless otherwise advertised. On September 21, an observational evening will be held in Room PL4 and the Observatory (weather permitting) when members will be delighted to provide views of the objects discussed in this article. In the event of bad weather, short talks and videos will be presented alongside informal discussion and an opportunity to get to know the Society. On October 5, we will be visited once again by Mr Gary Poyner of the Heart of England Astronomical Society, who will tell us about “Stella Nova”. For details contact the Secretary TAS on astrosecretary@gmail.com . Visitors and prospective members especially welcome.