August 2010 Night Skies over Tanzania
AUGUST 2010
Night Skies Over TANZANIA
By Dr N T Jiwaji
ntjiwaji at yahoo dot com
Click on the image below to get larger map
Click on the image above to get larger image
A first word: Mars will NOT be as big as the Moon on 27th August. This outdated story may have caught your eye, especially over the Internet. However there are many other more interesting things to see in the night skies this August.
Between 11th and 14th August, from two hours after midnight up to just before sunrise, the Perseid meteor shower is expected to blaze with more than 100 meteors per hour from a specific point in the northern sky in the Perseus constellation (hence the name “Perseid”). The high rate of meteors, also called shooting stars, compares with 5 to 10 meteors per hour that we expect any day, coming from random parts of the sky. The peak of the Perseid shower is on the night of 12th to the morning of 13th August.
Meteors are particles from space hitting our atmosphere, and the resulting heating due to friction with the air, produces a flash of light that we see as meteors. Did you know that 1000 tons of space dust is deposited on earth from space each year?
During 11-14 August, the earth will be passing through a dust trail left behind by the comet Swit-Tuttle when it passed close to earth in 441 AD. Since there are many more dust particles still left in that region of space covered by the original dust trail from the comet, we get 10 times more meteor activity. The Earth hits the thickest part of the dust trail on the night of 12 to 13 August. However, since the comet dust trail is broad, high levels of shooting stars can be seen between 11 and 14 August. Sometimes there are particularly large particles that hit the atmosphere and the sky lights up with brilliant light called bolides a sight worth staying awake for.
This year, there will not be any moonlight during the days of peak of the Perseid meteor activity so from dark-sky areas, away from the light pollution of cities, you should expect the maximum count. Even from cities you should still expect to see a few dozen meteors per hour.
The best way to observer meteors is to lay down comfortably on a mat on the ground with a clear view of the north eastern skies, and relax as you watch the meteor trails originating from a point in the constellation of Perseus. In August the Persueus constellation rises after 1 am in the north eastern skies and it will be at its highest elevation of 40 degrees above the horizon at 5 am, which is the best time to see the highest number of meteors,
The most interesting thing to follow in the night skies at this time is the dance of the planets and the Moon. On 10th August, brilliant Venus will be positioned between faint reddish Mars and sharp steady Saturn, forming a beautiful triangular configuration (see the picture simulated using the Stellarium software). Mercury is also visible below the trio. If you observe each night over several days, you can easily make out the shifting positions of the planets. The Moon joins the show on 12th, positioned between the trio and Mercury. On 13th it will be above the trio of planets as seen in the simulation picture.
Through a telescope, Venus is now seen as a half circle while Saturn shows its breathtaking rings clearly. Mars is not very impressive through a telescope and is seen a tiny dot only because it is nearly 300 million kilometers from Earth at the moment, compared to its closest distance of 100 million kilometers. The moon is always impressive to see through a telescope, especially when seen in its crescent to half moon phase. During these phases, the craters on the Moon are seen clear and sharp because of the contrast between lighted and shadow parts of the craters. Mercury can be seen only as a tiny dot through ordinary telescopes because of its small size.
Jupiter rises in the east at 9 pm so it is now at a very comfortable time for viewing. In fact you can easily mistake it for Venus if you are confused about the east and west directions, and since Jupiter rises in the east just as Venus in sets in the west.
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
The Milky Way stretches straight across the sky from southwest to northeast crossing the Southern Cross, the tail of Scorpio, the bow of Sagittarius, and Cygnus in the north.
The International Space Station will best seen on 21st August as it crosses the whole sky from southwest to northeast from 6:53 pm to 6:59 pm. On 20th August, though it will be low, around 20 degrees, it is more interesting to follow since it will pass between the Venus-Mars pair and Saturn and will disappear halfway across the sky. On this day it will rise late at 8:02 pm and disappear at 8:04 pm after passing between the planets.
ntjiwaji at yahoo dot com
END