August Night Skies over Tanzania

As the Moon powers its way through its orbit around the Earth, the day that Tanzanians await anxiously gets nearer. Idd-ul-Fitr will be celebrated towards the end of the month but the exact day is declared only after the first Moon has been sighted. For this to happen, the Moon has to be just off alignment with the Sun and Earth.

In its path around the Earth, once a (lunar) month, the Moon takes a position that brings it between the Earth and the Sun. By dawn of 29^th August, at 06:04 am, the Moon will be aligned exactly between Earth and Sun, a situation called the New Moon. By sunset that day, the Moon will have shifted away from alignment by only about 6 degrees and hence will be at an elevation of about 6 degrees above western horizon at sunset. This is too close for earth based observers to view the extremely thin crescent Moon in the glare of the setting Sun in the west. Within 20 minutes after sunset the Moon will also have dipped below the western horizon, making viewing extremely difficult.

However, by sunset of the following day, 30^th August, the moon will have shifted by another 12 degrees in its orbit around Earth and hence will be at an elevation of 17 degrees above the horizon at sunset. This gives quite enough time for the Sun to dip sufficiently below the horizon and the sky to darken enough, and the Moon to be more than 10 degrees above the horizon. This would give plenty of time for the crescent Moon to be clearly observed before it dips below the horizon just after 7:30 pm. On that day, the Moon will also at its perigee when it is nearest to Earth, making it appear significantly bigger and brighter and easier to see.

While looking for the crescent Moon on 30^th, seek out Saturn which will be about 20 degrees above the Moon. These are the last few days for us to enjoy the beauty of Saturn’s rings which show up clearly in even a small telescope like a hat on a on a head. After the beginning September, Saturn will no longer be seen in the evening skies until it reappears next February 2012. For those who have been following Saturn’s movement in the sky, the ringed planet is now significantly distant from the Virgo constellation star Porrima, since its closest approach to the star in May this year, showing the slow movement of the planet against the stationary background stars.

While Saturn sets in the west, giant Jupiter is beginning to raise its head in the East late at night. Late sleepers should not be surprised by a brilliant spotlight that appears in the eastern horizon around midnight.

Among the evening constellations are the long, winding Scorpio, and Sagittarius the archer. The Southern Cross lying on its side close to the southwestern horizon 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 13^th August the observations of the Perseid meteor shower will be marred by the Full Moon which will shine throughout the night and hence hide all but only the brightest of the meteors.

For the remaining days this month, the International Space Station (ISS) will be appearing low in the northern horizon around 8 pm. However, for several days from 28^th August the ISS will rise much higher and be a graceful object to observe as it crosses the sky, and sometimes disappears suddenly when it enters the Earth’s shadow in its flight 200 kilometers above Earth.

On 28^th August, it rises from the northwest horizon at 09:01 pm, crossing the middle of the sky and rising to an elevation of 53 degrees at 09:05 pm only to suddenly disappear a few seconds later – a spectacular observation to witness. The following day, 29^th August, it again rises in the northwest at 08:03 pm rises up near the northern horizon to an elevation of 30 degrees and sets in the east five minutes later at 08:09 pm.

On 30^th, soon after observing the first crescent Moon, you will see the ISS once again crossing the middle of the sky having risen in the northwest at 08:41 pm. It again disappears into the Earth’s shadow 4 minutes later at 08:45 pm close to the southeastern horizon. The path of the ISS on 31^st August is similar to that of 29^th but it rises at 07:43 pm and disappears in the eastern horizon five minutes later at 07:49 pm.

First and second September continue to provide spectacular views of the ISS with it hugging the south west horizon on 1^st September rising in the northwest 08:21 pm and disappearing in the southeast horizon at 08:26 pm. The most spectacular and brightest view of the ISS will be on 2^nd September as it crosses right across the middle of the sky from northwest horizon at 07:22 pm and setting in the south east 8 minutes later at 07:30 pm. For more exact timings and paths visit http://heavens-above.com/ and enter your position.