Equinox

Just how high is Mount Everest exactly? 8,848 or 8,850m? Or perhaps just 8,844.43m, as a Chinese official survey found in 2005?

The arguments should be finally over when the European Space Agency launches a spacecraft early next year to measure the Earth's gravity field and its geoid, the shape formed by the planet's mean sea level and its imagined extension beneath land.

The glamorously named Gravity Field and Steady-state Ocean Circulation Explorer, better known as GOCE, will allow scientists to measure and compare more accurately than ever before mountain heights across the globe, however remote.

From September the sky moves into its autumn phase, providing ample opportunities for us to observe the arcane beauty of autumn stars and constellations that, for a few months, were hidden behind the glare of the sun.
As night falls, the captivating zodiacal constellations of Pisces, Aquarius, Capricornus, and Sagittarius are visible across the sky from east to west.

Sagittarius the Archer is a happy hunting ground for astronomers, lying as it does at the very heart of the Milky Way. To locate this constellation, first find the Milky Way band overhead and follow it towards the southern horizon until you arrive at a group of stars that look like a teapot.

In the northern part of the sky are the constellations of Andromeda, Pegasus, Cygnus, and Hercules. Don't miss the chance to view Andromeda through binoculars. Can you spot a misty patch of light in the northern part of this constellation? This is the Andromeda Galaxy, our closest galactic neighbour and also the most distant object visible to the naked eye, lying a mere two million light-years away.

Planet-hunters are well catered for this month. Jupiter will be hanging high in the western sky during the evening, and I can assure you that viewing its four Galilean moons through a telescope is an experience of a lifetime. Pre-dawn sky-watchers can look forward to the appearance of Mars and Venus in the constellations of Taurus and Cancer respectively. Conditions are not good for observing Saturn this month as it sits close to the Sun. Even Mercury, at its greatest elongation east of the Sun on September 29th, is difficult to see as it sets within an hour of sunset.

Those of you wishing to celebrate the arrival of autumn should prepare for the autumnal equinox, when the Sun crosses the celestial equator on September 23rd, and night and day briefly become of equal length.

Now here's the coolest news ever. Google Earth engineers have flipped the software inside out, letting you travel the universe like you travel the earth. 'Sky in Google Earth' allows you to zoom around the heavens with various Hubble Space Telescope images highlighted. You can click on specific objects, like the Orion Nebula, and then see the Hubble photograph of the region.

And finally, science students at Trichandra College have recently formed the Nepal Astronomical Society (NASO). At a time when the government's planetarium and observatory project has stalled because of bureaucratic bungling, nothing gives me more pleasure than to see the energy of these young astronomers who want to do something on their own.

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