july2009nightskiesovertanzania

July 2009 Night Skies over Tanzania

NIGHT SKIES OVER TANZANIA

July Night Skies over Tanzania

By Dr. N. T. Jiwaji,

ntjiwaji at yahoo dot com

Click on Image to get a larger map

During this month, the world experiences one of the most spectacular solar eclipses on 22^nd July. However we in Tanzania will only hear about it since it will occur over Asia and the Pacific Ocean. This is the second eclipse this month with a lunar eclipse that took place during the Full Moon of 7^th July, but this was also not visible from Tanzania.

On the night of Tuesday past midnight on Wednesday 22^nd, while we in Tanzania are all sleeping, past midnight, people in India will wake up to a Sun that will be covered up by the Moon. The Moon’s shadow will make the early morning become night time again. The total solar eclipse occurs in Asia, a region with the highest population in the world. So the path of total darkness will pass over numerous cities as the eclipse progresses from India to China and into the Pacific. At maximum eclipse, the total period of darkness (totality) will last a very long time, nearly 7 minutes, which is the longest period that will not be repeated for another 133 years. If you can afford to stay awake on the night of Tuesday into Wednesday 22 July, you can watch live fees of the eclipse for various cities in India and China, Google the event to get a suitable link on the Internet.

Faster than light – can you imagine that! You will remember your Physics teacher telling you that nothing can travel faster than light. But an amazing experiment has been reported last month where researchers at the Los Alamos Lab in the US, and Cambridge and Oxford in UK, have made radio waves travel faster than the speed of light! And be assured that Einstein’s special relativity laws set out in 1905 are not broken in the process because radiowaves, which are massless, are made to travel faster.by boosting the polarization current using a “Polarization Synchroton” machine. This is a truly ground breaking discovery that can explain help to explain why pulsars (super-dense spinning neutron stars) emit very powerful waves that have baffled scientists.

Another significant news last month was conclusive finding of uranium on the Moon. The discovery was made from data sent by the Kaguay spacecraft. This important element which is a fuel for nuclear energy was not seen in previous investigations. Other elements observed were thorium, oxygen, magnesium, silicon, calcium, titanium and iron. The discovery will reduce the pressure on the limited amount of uranium on earth and can be a source of fuel for outerspace explorations launched from the moon where the gravity is only one sixth of that on earth, making launches easier with less energy required.

The night skies are now cool dry and very stable with crisply shining stars – perfect weather for arranging stargazing activities all over Tanzania and East Africa. The most interesting star this month will be the attractive and brilliant Jupiter which rises in the east just before 9 pm. A few days back on 10^th July you may have seen a beautiful paring of Moon and Jupiter about 3 degrees apart rising majestically in the east. The pair will again be seen similarly close together is on 6^th August with the moon brilliant in the Full Moon phase. So watch out.

Jupiter will be our constant companion the next 7 months until next January. Through a telescope it shows clearly the paralled equatorial bands of clouds and of course the four Galilean moons that appear as pinpoints along the equatorial line. They change positions even over a few hours so are interesting to follow.

Saturn is high in the western sky at sunset and sets after 11 pm. The flat plane of its ring system is getting close to line up along our line of sight and will disappear from view even through a telescope. It will be good to watch now to find out when they disappear from view. Between 24 and 26 July a thin crescent Moon will be close to Saturn with them being closest on 25^th.

Mercury is the most difficult planet to see since it is always seen very close to the sun near the horizon at sunset (or sunrise). Bu this month it begins a rapid rise from behind the sun to reach an altitude of 15 degrees above the horizon at sunset at the end of the month. So we can catch it this time since it continues its rise during August and reaches nearly 25 degrees altitude, which should make it visible to see though it is the smallest planet in our Solar system.

Brilliant Venus and red Mars are close together in the dawn skies near the eastern horizon, separated by about 5 degrees only. In the middle of the month they are joined by a waning crescent moon with the three heavenly bodies in a line, called the ecliptic which shows that the planets all move in one flat plane around the Sun. On 18, 19 and 20 July the three are close together presenting beautiful changing triangular shapes. On 19^th the trio will present the shape of a right angled triangle with Venus at the right angle (90 degrees) position.

As for the stars, the southern skies are filled with very bright stars that would be hard to hide! The north and south direction pointers, that is the Big Dipper and the Southern Cross, are still high enough in the evening skies and can be used to mark the north-south direction very well. Scorpius in the dominant constellation this month, occupying the overhead evening sky with its three stars forming its tentacles, the red star Antares in its neck and a long winding tail that ends in a close pair forming the sting. Scorpius is the only constellation that does full justice to its namesake, the scorpion and is unmistakable to even a casual stargazer. Use this opportunity to start (or continue) your stargazing hobby by independently identifying a constellation! Below Scorpius, try to identify Sagittarius (the archer). This constellation marks the direction of the center of our Milky Way galaxy and you will notice dense concentration of stars here. The band marking the Milky Way contains numerous stars and dust patches and stretches from the southwest, passing through the Southern Cross and Sagittarius and upto Cygnus (the swan) in the northeast. Leo (the lion) with its distinctive inverted question mark head is low in the western horizon and will be lost after this month.

Among the brightest stars noticeable in the July skies are: Alpha and Beta Centauri in the south form the pair that points continuously towards the Southern Cross; the fourth brightest star Arcturus is overhead towards the north and the fifth brightest star Vega rises in the northeast. Other bright stars you will easily notice are Altair which rises in the east and Spica, the brightest star in the Virgo constellation can be seen almost overhead towards the west. A gibbous (almost full) moon will be seen close to Spica on 31 July.

Among the artificial satellites that we can see this month, the most interesting is the Hubble Space Telescope (HST) on 21^st and 22^nd July. The HST will rise in the direction slightly south of west at about 7:25 pm and will be visible for about 8 minutes as it rises up, passes very close to Saturn and dips down after rising to a maximum height of 73 degrees on 21^st and 43 degrees on 22^nd, in the North West sky. It will set in the north east at about 7:35 pm. Begin early to orient yourself to face the west and trace out an imaginary path that it is expected to follow as described here. Watch out for a moving star like point along this path. The International Space Station, ISS will be best seen early next month on 6^th August around just before 7 pm rising from the North West direction, rising to 60 degrees and setting in the south east five minutes later.

A note of caution before we end – as explained last month, do not be fooled by stories of Mars to be seen as big as the Moon next month. Mar is in the early morning sky and seen as a modest red star.

END