This month of high summer is a period of lunar and planetary manoeuvrings, though unfortunately most of this action takes place after midnight in the early hours of the morning. First Mars has a close encounter with Jupiter, then the Moon hides Saturn, skims past Neptune and occults some of the stars in the Pleiades. Also we will be treated to a great display of the Perseid meteors.
This month the Milky Way arches overhead this month, looking ever more resplendent as the skies grow darker. Set against its glowing band, three brilliant stars, Vega, Deneb and Altar mark the corners of the Summer Triangle.
This is also the time of year to look at the southern constellations and the Galactic centre of the glorious Milky Way.
The constellation of Sagittarius is supposed to be a centaur. That’s a mythical half man/half horse creature, carrying a bow and arrow. Good luck spotting the centaur in the stars!
But these same stars also make up what sky watchers call the Teapot in Sagittarius; and the Teapot is simple to spot. The Teapot is an asterism in the western part of the constellation. It’s best viewed during the evening hours from about July to September. Best of all, when you’re looking toward the Teapot, you’re also looking toward the centre of our Milky Way galaxy.
The Plough lies north west with the ‘W’ of Cassiopeia at the same height in the north east. The four stars that make the square of Pegasus are becoming more noticeable in the north east and the summer triangle of stars Altair, Deneb and Vega are still very dominant in the summer sky. Arcturus is dropping to the west while Antares is now past its best.
The southern part of the sky is still taken up by the formless Hercules, Ophiuchus and Serpens. Yet more dull constellations are appearing low in the south east; these are Capricornus, and Aquarius, and although both lie in the zodiac there is nothing else to recommend them.
An indication that summer is drawing to a close is the return of Orion the hunter in the eastern pre dawn sky. Sometimes called the ‘Ghost of the shimmering summer dawn’. If you’re up early and have an unobstructed view to the east, be sure to look in that direction in the hour before dawn, The Hunter, recently behind the sun as seen from our earthly vantage point and now ascending once more before sunrise. The Hunter rises on his side, with his three Belt stars; Mintaka, Alnitak and Alnilam pointing straight up. This August, there’s a very bright object not far from the Hunter, also in the east before sunup. It’s the planet Venus. Watch for them both.
The Planets:-
MERCURY
The innermost planet reaches its greatest separation from the Sun on 10th August, but as far as observation goes it will be lost in the glare of the Sun.
VENUS
The evening star skulks low in the evening twilight to the west, falling below the horizon about 9pm. Although its more brilliant than any of the stars, at magnitude –3.9, you will needs binoculars of a low power telescope to spot it against the residual glow from the Sun. If you fancy a challenge, try and spot Venus with the slender crescent Moon on 5th August.
MARS
At the star of August Mars lies to the right of Jupiter, rising a few minutes earlier and 20 times fainter at magnitude +0.9. The two planets form an equilateral triangle with the red giant star Aldebaran (which will have the same brightness as Mars). The red planet will be moving rapidly leftwards, and the two planets have a close conjunction on the morning of 15th of the month, when Mars lies only 20 arcminutes from Jupiter. The crescent Moon forms a lovely grouping with Jupiter and Mars, plus the Pleiades and Aldebaran, on the mornings of the 27th and 28th August.
JUPITER
The gas giant is rising over the horizon around 12.30am. It will be in the constellation of Taurus. It dominates the rest of the night sky, with a brilliant magnitude of –2.2. AS mentioned above the gas giant planet will be waltzing with the Moon and the red planet Mars towards the end of this month.
SATURN
Located in the constellation of Aquarius, Saturn shines at magnitude +0.7 and will be rising above the horizon around 9pm. The Moon occults the ringed planet in the early hours of the 21st. It will be the first lunar occultation of Saturn visible from Britain since 2007.
URANUS
You will find Uranus in the constellation of Taurus. The seventh planet rises around 11.30pm, and shines at magnitude +5.8.
NEPTUNE
You will need a pair of binoculars to spot Neptune lurking in the constellation of Pisces. It has a very faint magnitude of +7.7, and rising above the horizon about 9.30pm. There is a convenient chance to locate this distant world around 10.30pm on 21st August, when it’s the faint star, one sixth of a lunar diameter above the top edge of the Moon.
PLUTO
This distant planet can be observed in a ten-inch or larger telescope. It can be found in the constellation of Capricornus. With a magnitude of +14.4 it descends below the horizon about 3. 20am.
CERES
The largest object in the asteroid belt can be located in the constellation of Sagittarius this month. At magnitude +8.16 it falls below the horizon about 12.35 am.
Special events:-
5th August – A pair binoculars will show the narrowest crescent Moon just to the right of Venus, very low in the west after sunset.
10th August – The crescent Moon will be near the bright star Spica.
21st August – Between 4.28 and 5.21am, the Moon moves right in front of Saturn, hiding it from view. Saturn re-emerges in the morning twilight. At 10.30pm the Moon passes 5 arc minutes from planet Neptune.
25th August – The almost half Moon is very near to the Pleiades star cluster.
26th August – I the early hours after midnight the last quarter Moon passes through the lower part of the Pleiades. The occulted stars include Atlas, one of the seven sisters, which is hidden between 4.50 and 5.3am. It will be a wonderful sight in binoculars or a small telescope.
27th August – Jupiter lies below the Moon, with Mars and the star Aldebaran to either side.
28th August – In the early hours, you will find the crescent Moon to the left of Mars, Jupiter and Aldebaran.
30th August – The crescent Moon will be near the twin stars of Gemini; Castor and Pollux in the early hours after midnight.
Meteor showers:-
He nights of the 11th, 12th and 13th August will be the maximum of the Perseid meteor shower. It will be an excellent year for observing the usual abundance of fast, bright shooting stars. The Perseids are connected with comet Swift-Tuttle which was discovered by Lewis swift and Horrace Tuttle in 1862. The comet takes 133 years to orbit the Sun.
Phases of the Moon :-
New Moon 4th August
First quarter 12th August
Full Moon 19th August
Last quarter 26th August