IDD CRESCENT IN AUGUST NIGHT SKIES
With the end of Ramadhan only a few days away, the prospect of joyous Idd holidays turns people's attention towards astronomy as they plan their strategy to view the Idd crescent. Nane Nane day, which pays tribute to farmers, overlaps with Idd next week, so people will appreciate the importance of the starry skies above and lush soils below to complete their view of the Universe.
Astronomical New Moon, occurs when the Moon is aligned with the Sun. This month, New Moon occurs just after midnight of August 6 at 00:50 am. By sunset of the following day, August 7, the Moon will have only 18 hours to move in its orbit around Earth, which also takes it away from its alignment with the Sun. This time is not enough to allow the Moon to shift sufficiently away from the Sun and away from the horizon brightness.
At sunset on August 7 the Moon will be only 6 degrees above the western horizon. So though the Moon could be viewed (WITH CARE) using a telescope, our eyes cannot detect the extremely faint and thin crescent.
Each day the Moon moves by about 12 degrees completing a monthly full circle of 360 degrees in 30 days. By the evening of August 8, on Nane Nane day, the brighter thin Idd crescent will come into view 17 degrees above the western horizon from 6:30 pm, as the sky darkens while Sun slides below the horizon.
Idd can be expected to be celebrated on 9th and 10th August providing an extra-long weekend of celebrations.
The solar eclipse of November 3 is only a few months away so this is the time to prepare yourself. The solar eclipse will occur when the Moon comes between the Sun and our Earth and the three will be so perfectly aligned over a distance 150 million kilometres that the shadow of the Moon falls on Earth. This eclipse will be seen all over Africa, so it is an exciting opportunity to bring the wonders of astronomy to the public. The north and south halves of Africa will experience different amounts of sun being covered by the Moon.
In Tanzania, about 70 percent of the Sun will be covered by the Moon. However, in the central parts of Africa, the eclipse will be total, covering Sun completely for about a minute. The parts where the day will turn to night during the total phase of the eclipse is a thin 100 kilometre wide path from the seas off the west African coast, entering the continent at Gabon to into the two Congos and entering East Africa in northern Uganda and on to northern Kenya, and finally into Ethiopia and ending at sunset just inside Somalia.
The best place to view the total solar eclipse that will be closest to us and reachable by road is at Gulu in Uganda. Due to the rainy season that will be beginning at this time of the year, clouds will pose a big challenge. The chance of cloud at Gulu is 80 percent, but they may part sufficiently to allow viewers to steal a view of this wondrous event. That November 3 evening will certainly turn to night for a minute, even if the is Sun behind clouds.
The adventure of travel and experiencing different cultures can be an additional motivation for such an eclipse viewing trip. Schools and communities are encouraged to arrange their group tour by bus to Gulu, Uganda to participate in this eclipse event brought to us from the heavens. More details of the eclipse and tips for planning an eclipse excursion can be found at the Astronomy in Tanzania website http://www.astronomyintanzania.or.tz
Venus continues to rise up in the western sky and you just can’t miss this extremely brilliant star shining 35 degrees above the horizon. Saturn still occupies the overhead skies 70 degrees above the western horizon shining with a steady piercing brightness. Venus and Saturn lie on opposite sides of Virgo (the Virgin) constellation, with its brightest star Spica in between.
Moon will be closest to Venus on August 9, while on 12th and 13th it will be close to Spica and Saturn. It will be in First Quarter (half disk) phase on August 14 and Full Moon phase on August 21.
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 Perseid meteor shower will peak on August 12. With no Moon in the sky after midnight, to hide the fainter meteors, you can expect to see more than one meteor per minute or 80 to 100 meteors per hour. The best time to view the meteors, popularly known as shooting stars, is just before dawn. At dawn time, Earth will be travelling at 100,000 kilometres per hour heading straight into the dust left behind by the Swift-Tuttle comet. The dust burns upon friction with the earth’s atmosphere and we see the bright burns as shooting stars. The meteors will appear to be originating from the area around the Perseus constellation which rises after midnight from the north-western horizon, and will be highest above the northern horizon at sunrise.