Astro-Tour of February 2012 Night Skies
Astro-Tour of February Night Skies
Press here for Kiswahili version of this article
Astro-tourism is an upcoming trend for western tourists who lack a clear view of stars in their own countries due to the extremely bright lights used in urban areas. Our eyes become blinded by powerful lights. Furthermore, most of the city-lights also shine upwards, which gets scattered back to us by the atmosphere. This creates a lack of contrast between the stars and the artificially bright sky. Most stars are too faint to be seen in such a bright sky. This is also the same reason why cannot see stars during the daytime because the atmosphere is brightened by scattered sunlight. It is like daytime during the night. Unnecessary lights cause light pollution of our environment; a problem that is beginning to be felt in our cities also.
In Tanzania, there are still vast areas with extremely dark skies because most of our country is not densely urbanized. This is especially true in the nature reserves and national parks, which are protected for the benefit of wild life. Fortunately, this means that we are conserving our dark skies and hence indirectly protecting them from light pollution.
Even in large urban centers such as Dar es Salaam, the nights are quite reasonably dark for us to be able to see most of the bright stars. Out of the about 3,000 stars that one can see in very dark places, in urban centres we can see about 300 of the brightest stars. These are enough to allow you to recognize the major constellations and star clouds (nebulae).
Though the dark skies will be a great attraction for foreign western tourists, we ourselves tend to take for granted the beauty of our night skies. While they have to spend thousands of dollars to follow the stars, we can just step out of our houses and enjoy the beauty of the sky that surrounds us.
Not only that: While you would have to travel large distances to see all the places in this world, the sky comes to us!! The stars in the sky above us shift continuously so that in one night we are able to see the entire sky that surrounds our Earth. This is because the Earth rotates on its axis every 24 hours. The sky also shows different stars when viewed at the same time every couple of weeks. This is because the Earth revolves around the Sun. So each month we face quite different parts of the sky at night. Hence by only watching the sky at one convenient time in the evening, we can see the whole sky in one year.
Hence, we do not have to spend money to go and see different parts of the sky. We can just step out of our houses and watch all the stars in the entire skies by watching them over one whole night or at the same hour at different times of the year.
So get up from in front of the TV or from the cozy club away from your drink, or even out from your office for those late workers, and go out and become an astro-tourist by letting the stars come to you. You just have to turn your head up or lie comfortably on a mat under the cool night sky. A small investment in a telescope or binoculars will increase your enjoyment many fold.
This February you can see the following interesting stars and planets in the skies.
The Moon is the most common astronomical object in our sky. However, it is best seen around the time when it is in half phase, that is, mid-way between the New Moon on February 22nd and Full Moon on 8th March. Therefore, the best dates for Moon observation are around the end of February.
This February is a unique month because you will be able to see ALL the visible planets in the first half of the night. The last days of February will also bring your attention to two of the brightest stars in the sky at the moment. Actually, these planets Venus and Jupiter shine as two brilliant sparkling skies in the western skies from sunset up to 9 pm. Between 25th and 27th of this month, a beautiful crescent Moon will join the brilliant pair. Through a modest telescope, Venus is seen as almost half disk, while Jupiter will show its four Galilean moons and parallel equatorial cloud bands.
Another very bright planet that will be seen this month rises in the East just before 8 pm and is seen the whole night as it crosses the sky to the Western side as the night progresses. This planet is Mars which shines noticeably red. It will be brightest on 5th March when it rises exactly opposite to the setting Sun. It is the reflected light from the planet’s surface that we see as a bright red shine. Through a good telescope, you would see its red surface and a white polar ice cap. The Moon will be close to Mars on 7th March when it is in almost Full phase.
On Leap Day, 29th February, you will witness a remarkable line up of four planets and the Moon across the sky from West to East. Soon after sunset around 7 pm that day, watch out for Mercury low in the western horizon, with brilliant Venus above it, about 30 degrees up from the horizon, followed above it by bright Jupiter about 40 degrees up in the sky, and further above it you will see an almost half Moon about 50 degrees above the horizon. All these are lined up along a line called the Ecliptic. It is only along this path that you can see any of the solar system objects such as the planets, the Moon and the Sun because our Solar System is a flat system with everything in it in one huge flat plane. If you follow the line made by Mercury, Venus, Jupiter, and the Moon across the sky to the other side in the East you will find that Mars rising in the East is also positioned along this same ecliptic line.
The last of the visible planets, Saturn rises just around 10 pm, early enough for everyone to enjoy its sharp steady brightness. Though it does not shine much, you can detect it by watching out for a star that shines without twinkling, especially if you compare its twinkling with other nearby stars. Through a telescope Saturn is the most remarkable planet that you can see because of its set of flat rings that surround the planet. It is one of the most beautiful sights that you can see through a telescope.
The Milky Way cuts across the sky through the middle from south-south-east to north-north-west. The constellations that are within the path of the Milky Way are CANIS MAJOR with its brightest star Sirius, ORION with its numerous nebulae, TAURUS with its star clusters, the Hyades and the Pleiades, PERSUS with its famous Andromeda galaxy, and finally the W shaped CASSIOPEIA in the north. A new addition this month is the FALSE CROSS, an asterism that closely resembles the SOUTHERN CROSS but whose long diagonal does not point south. Locate it after 9 p.m. as it rises in the southeast. LEO (the lion) raises its head in the east at 8 p.m. and should be easily recognizable by 9:30 p.m.
Five of the top ten brightest stars can be recognized using the star map: The brightest star is Sirius, followed by Canopus, the second brightest star that can be seen towards the south. Rigel is in ORION , Procyon is to the east, Achernar will be setting in the west and Betelgeuse is in ORION. After 10 p.m. they will be joined by Alpha- and Beta-Centauri, the brightest stars rising below the SOUTHERN CROSS.