AUGUST NIGHT SKIES OVER TANZANIA

August Night Skies Over Tanzania

Two planets, Mars and Saturn, and a star Spica struggle for position in the western sky this month, half way up the sky.. Since April this year, after a short stay in Leo constellation, the red planet Mars has been moving stealthily eastwards across the background stars towards Virgo constellation. It is now in its pro-grade (normal, west to east) movement across the skies and is close to and below the Saturn-Spica pair. By August 14, it will be exactly in line between Saturn and Spica. Ater that it will continue eastwards leaving the Saturn-Spica pair well behind.

This is the best time to see distinct changes in the sky where stars normally maintain their relative positions for thousands of years. There is an almost day by day change, and in fact, between 12^th and 18^th you will see distinct difference each night as the trio change shape, from triangle now, to a straight line on 14^th, to a more and more stretched triangle on the other side. By August 20, a beautiful crescent Moon joins the trio and the shapes become even more interesting to watch with Saturn, Mars and Moon forming a perfect straight line on August 21.

As we watch Mars from the Earth, keep in mind that a new spacecraft has just landed on its surface on August 6, after an 8 month, 600 million kilometer journey. The car-sized rover, named Curiosity, will spend the next two years exploring the surface of the red planet for sign of life.

The south-west sky is also the home of a dense collection of stars that rises straight up from the horizon into the sky, in a bright path called the Milky Way. The numerous stars in this Milky Way are actually part of our own flat spiral galaxy known by the same name. This bright path in the sky this August shows so many stars and brightness because you are watching it from within the Milky Way Galaxy, towards its center and along its flat plane; hence our line of sight cuts through myriads of stars. On either side of the Milky Way, the sky will be distinctly barren of stars since there are not many stars that cut our line of sight across the thinner part of our flat spiral galaxy system.

Two easily identifiable constellations are also in the south western skies this month. High in the sky is Scorpio whose stars form an immediately recognizable shape of a scorpion.

Lower down towards the horizon you will see two very bright stars pointing vertically down. The upper very bright star is Alpha-Centauri (or Rigel Kent) which is the closest star to us (after the Sun), at a distance of about 4 light years - meaning that light, travelling at 300,000 km/hr, takes 4.4 years to reach us, yet this is the closest star!!

The bright vertical pair points towards another prominent constellation, called the Southern Cross, with a shape of a kite. The long diagonal of the kite points directly towards the South. Be careful that since it is now almost parallel to the horizon, after 9 pm it will be exactly parallel to the horizon and hence will point towards the south celestial pole which is about 6 degrees above the horizon for us in Tanzania.

In the early morning skies in the east, watch Jupiter rise at 1:30 am (for example while watching the Perseid meteors on the night of August 12/13). Venus rises two hours later around 3:30 am. By sunrise, Mercury has joined the show, forming a straight line with Jupiter, Venus and the rising Sun. This line is the path, only along which you can see planets, since they orbit the Sun in an almost completely flat plane.

Among the evening constellations are the long, winding Scorpio mentioned above, and Sagittarius the archer. The Southern Cross (described above) lies on its side close to the southwestern horizon and points south. In the north you can make out Cygnus the swan as a cross with the bright Deneb (A) at its tip. Among the bright stars you can try some with famous names. These are, from west to east, Spica (B) in constellation Virgo, Arcturus (C), Alpha (D) and Beta Centauri (E) the two bright stars in the southern skies that point to the Southern Cross, the red star Antares (F) in the neck of Scorpio, Vega (G), Altair (H) and Deneb (A) all in the north and Fomalhaut (J) just rising in the east at 8 p.m

On night of 12/13 August for three hours after midnight you can observe the peak of the Perseid meteor shower. About 10 meteors (falling stars) per hour are expected to be seen and will seem to be originating in the region of the Perseus constellation in the north east. A crescent Moon rises at 2:45, so can spoil the viewing of smaller meteors.

Bright space craft that can be seen this month is the Chinese Thiangong Space Station on August 13, when it will rise from the north-west horizon at 7:29 pm and will rise high in the zenith skies to about 80 degrees and will disappear in suddenly at 7:32 pm when it enters the Earth’s shadow. On 15^th August 15, it will rise from the north-west horizon at 6:46 pm and will rise to about 50 degrees in the south west and will set in the south east five minutes later at 6:51 pm.

The International Space Station (ISS) will be seen early next month on September 4, 5 and 7, so visit www.heavens-above.com for exact times, and www.astronomyintanzania.or.tz for further details.

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