28-07-2007 August night sky (Article 96)

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Simon Kenny
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Location: Shannon, Co. Clare, Ireland

28-07-2007 August night sky (Article 96)

Post by Simon Kenny » Wed Feb 04, 2009 11:13 am

August night sky (Article 96)

Whether you are at home in the Mid West or on holiday do try to have a look at the night sky around the 12th August. This is the night when the annual Perseids meteor shower peaks and next week’s article will be about this event. Hopefully it will be reasonably warm then because the best way to view a meteor shower is not with a telescope or binoculars but in a reclined position in a garden lounger and just use your eyes to observe.
The stars of the Plough lie low in the north, while over across the Pole we see Cassiopeia in the MilkyWay, which this month runs SSW through the zenith to NNE. High in the east is the Square of Pegasus, and on the horizon the straggling Pisces, both heralding in the stars of Autumn. The bright orange star Arcturus in Bootes is above the western horizon, with late spring stars of Corona Borealis and Hercules SW of the zenith.
But what’s happening to our usual nearby residents this month? Well, of our solar system neighbours the Moon is classified as waning gibbous on the 1st August with about 90% of its disc illuminated by sunlight, as seen from Earth, and is 17.8 days old. New Moon is on 13th August and you will notice that it will gradually ride a little higher in the night sky through August and on into autumn and winter. This is because the Earth’s plane is tilted relative to the Sun and during the Northern Hemisphere’s winter the Moon is at its highest in the night sky.
Jupiter, the great gas giant and known as Lord of the planets, has an equatorial diameter of 11.2 times greater than Earth’s! Just as in July it is low in the southern sky and it sets at 15 minutes past midnight on 1st, about 11:30pm on 15th and by 31st it will set at 10:20pm. — make the most of it while you can.
Venus, which has been shining very brightly for some months now by reflected sunlight from its totally clouded and poisonous atmosphere is dangerously close (for observing) to the Sun from Earth’s point of view. (Warning: do not use a telescope or binoculars with the Sun above the horizon — instant blindness will occur). If you remember from our July night sky article we explained that Venus’s orbit is closer to the Sun than Earth’s and in the last few months we have been seeing Venus getting bigger and brighter as it came towards Earth in this orbit. Well, now it has swung between Earth and the Sun and is starting to go away from Earth as it heads off to do another lap around the Sun. A consequence of this is that when it was coming towards us we saw it on the left hand side of the Sun (after Sunset), but now it is on the right hand side and we will see it rise just before the Sun at about 5:30 am on the 25th.
Saturn sets at about 9:00pm on the 1st, but it too is dangerously close to the Sun as seen from Earth. Mars will not be visible in the night sky during this month.
Want to learn the constellations, brighter stars and locations of more famous night sky objects? -- then come along to our next meeting at 8:00pm on 1st August, in room 206 Mary Immaculate College. Clear skies!

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