Skywatch August

AUGUST brings the promise of longer, but still warm, lazy nights spent out under the sky. 

This month is most famous for the Perseid meteor shower, of which more later, but our month to month observations of the planets continue, as well as exploring one of the prettiest of constellations, Cygnus.

Planets

Jupiter remains visible throughout August, setting around 23:30 in the early part of the month.  The ringed giant, Saturn, is visible from 21:30 onward; just look towards the southern horizon for a bright point.  Binoculars show that there is something unusual with the planet, whilst a small telescope shows the ring shape clearly.

If you’re up early, Venus rises to greet you from 03:30 shining brilliantly in the east.

On the 25th August, you’ll see the twins of Gemini, Castor and Pollux, directly above Venus. Also known as the Morning Star, Venus is in some respects the Earth’s twin, but as it is nearer to the sun, its corrosive, pressured atmosphere, coupled with its scorching surface temperature makes it inhospitable to life.

Mercury and Mars are too close to the sun to be visible this month.

Constellation

This month’s constellation is Cygnus, the Swan, also known as the Northern Cross.  Although considered a summer constellation, Cygnus is actually visible for a large part of the year – I have seen it setting and rising in January! It is particularly notable as the Milky Way (the edge of our Galaxy) appears to run through it.

In legend, Cygnus is linked to several swans of significance; the God Zeus transformed himself into a swan for his nightly ramblings, and Orpheus was transformed in a swan after being murdered.  Whatever legend gave rise to the name, Cygnus is a beautiful, easy to spot constellation, with several binocular objects to spot.

The head of Cygnus is represented by the blue-gold double star Albireo.  Lying 380 light years away, you can spot that Albireo is two stars in larger binoculars, whist a small telescope shows them clearly.  The tail of the Swan is the star Deneb, a blue-white super-giant around 200 times bigger than our sun.

Cygnus contains two open clusters, Messiers (M) M29 and M39.  M39 is reminiscent (at least to me) of the Star Trek “arrowhead” logo, and M29 like an H with no middle bar.

To find Cygnus, look to the south east at around 22:00 to 22:30 and you should be able to pick up Cygnus in a vertical position (Deneb at the top, Albireo at the bottom).  To locate M29, locate Deneb (the Swan’s tail), then head to the “nail” of the cross and drop down a little and with keen eyesight and good binoculars, you may well spot M29; for M39, I follow from Albireo to Deneb then keep roughly on a straight line and M39 should pop into view.

The Perseid Meteors

One of the richest meteor showers of the year occurs on the 11th/12th August.

The Perseids, which can produce up to 60 meteors per hour, occur when the earth’s orbit takes us through the debris left behind by a comet named Swift Tuttle.    

Each meteor is no larger than a grain of sand but shines brightly for a fraction of a second.  This year, we have the Moon around all night, so the show won’t be as easy to see, but nevertheless, if it’s clear, just lie back in a reclining chair and enjoy the sky!

The meteors are known as the Perseids as they appear to radiate from the constellation Perseus, which will be rising in the North East on the morning of the 12th.