If, during the second half of the month of August, you have some time to spare during one clear evening around 9 o?clock, take the trouble of going outdoors and look at the sky eastwards. You will unfailingly be caught by the sight of a very bright reddish star quite high above the horizon, the brightest one in this region of the sky. This is in fact not a star at all but planet Mars which this August is making its closest approach to Earth in several thousands of years.

The naked eye sight of Mars will be the more impressive as there will be no stray light shed by the Moon, which will be new at the time. Owners of telescopes can try to catch a glimpse of the planet through their instruments but markings and other surface details will be well seen only in the largest instruments under very stable skies. Unlike planets Jupiter and Saturn which are eye catching in almost any astronomical equipment, Mars has always been a challenge, even at its best, because of its small intrinsic diameter: the planet?s radius is only half that of the earth. To make matters worse, its surface is often veiled by severe dust storms further masking details. It is this planet?s poor telescopic appearance, coupled with low standards of telescopic equipment in the 19th century, which led to several observers reporting that the planet had ?canals?, triggering what would later truly become a mad hunt for martians. The american astronomer Percival Lowell, who was passionately committed to finding proof of intelligent life on Mars, built a telescope dedicated to this task in 1894. This search for Martian extraterrestrial intelligence would be shattered only by the first images of the planet by the Mariner and Viking probes in the 1970?s showing for the first time breathtaking but otherwise perfectly desertic scenery totally devoid of manifestations of intelligence.

Five new missions

Amateurs or professionals alike could not miss this year?s exceptional proximity of the red planet. As the lesser distance implies less travel time and thus better fuel economy, there are no less than five space missions well on their way to Mars. First there are two mobile surface rovers built by NASA. These are two small automated vehicles like the Mars Pathfinder mission of 1997 whose live images from Mars spread over the internet then broke all connection hits since creation. Then, there is Europe?s first Mars mission, called Mars Express, which will essentially be an orbiter but also carrying a small lander unit, Beagle 2, which will detach itself and land. Finally, to complete this small but technologically advanced battalion will be Japan?s probe ?Nozomi?. This word, meaning ?hope? in Japanese, is a well acquired name as this Japan?s first interplanetary mission nearly ended in disaster when launched in 1998 because of several technical glitches including damage to sensitive electronics due to solar flares. It will be indeed a feat if the probe is able to reach its target early in 2004 in operating condition. These five new missions will meet orbiters Mars Global Surveyor and Mars Odyssey already there since 1996 and 2001 respectively. Indeed, no planet other than the Earth will then be under so close scrutiny since the era of space exploration has begun.

The map shows the sky as it appears if you look, from any location in Mauritius, towards the East around 9 o?clock during the second half of August. Planet Mars is high above the eastern horizon in constellation Aquarius. The only bright star in the vicinity is Fomalhaut (in constellation of the southern fish) to the right of the red planet. Further to the South East and lower in the sky will be bright star Achernar in the constellation of Eridanus, the celestial river. The Great Square of Pegasus, the flying horse, can be seen to rise North East. If the sky is dark enough and with no excessive light pollution around, an observer should have no trouble in seeing the Milky Way. It appears as a faint band of fuzzy light (not to be mistaken for clouds) crossing the sky from North East, passing overhead in constellations Scorpius and Sagittarius, and down South West in the Southern Cross and Centaurus.

Unlike the conspicuous constellation Scorpius high above, constellation Aquarius in which Mars is found is not composed of bright stars with no bright nebula or cluster of stars worth a sight in small instruments. Yet, binocular owners should take advantage of the absence of Moon to really make the most of the Milky Way above. Sweeping the instrument through the rich star fields overhead in Scorpius and Sagittarius will be a most memorable experience. Indeed, a simple pair of good binoculars, such as the widespread 7x50 models available from camera stores, is all what a casual observer might really need as a beginning instrument. Instead of purchasing a telescope, which will be expensive and difficult to use by the novice, it is rather advisable to begin with a pair of binoculars and a good star chart such as the Star Disk (available locally at Rs 200 in good bookstores). Such modest equipment will already open up a whole world of nebulae, star clusters and even bright galaxies, with the purchase of more powerful equipment only justified after the basics of star gazing having been grasped.

We shall end our star hopping exercise with a brief overview of the visibility of the other naked eye planets in August. Mercury is at its evening best mid month as a bright point of light West setting almost two hours after the Sun. Planets Venus and Jupiter on the other hand remain practically invisible as they pass behind the Sun?s disk. Finally, Saturn can be seen towards the North East in constellation Gemini rising some three hours before the Sun. Regarding our own Moon, its phase will be Full on the 12th and New on the 27th.

Ricaud Auckbur

Président société astronomique de Maurice