A classic example

Ken Kennedy of Dundee Astronomical Society tells us what to expect in the night sky in July. “The night sky during July is still quite bright, but, from the 15th, it becomes slightly darker and it will be possible to see the less spectacular constellations of the summer,” he says.

“There are still a few bright stars in the sky at 10pm. Arcturus is quite high towards the south-west and the Summer Triangle – marked by the stars Vega, Deneb and Altair – is making its way towards its maximum elevation at around midnight. Vega, the brightest star of the constellation Lyra, will catch the eye as it is the fifth brightest star in the sky.

“Vega appears white as it is hotter than our sun and is bright because it is only 25 light years away. Because of the earth’s ‘wobble’ Vega will be our pole star around the year 14,000 AD. It can be used to lead us to an interesting object in Lyra which will become more easily visible as the skies darken.

“Not far south of Vega are two stars which are quite close together. Looking with a small telescope along a line between these stars you will come across a small, but bright oval looking like a tiny smoke ring. This is the Ring Nebula, alternatively known as Messier 57.

“Because they looked like planets in early observations, they became known as planetary nebulae and the Ring Nebula is a classic example. We now know that these objects are the result of the final end of stars of similar size to our sun. When their fuel runs out, the stars become unstable and shed a ring, or perhaps multiple rings of material while what remains contracts down to a small white dwarf star.

“A larger telescope can see the detail and colour of the expanding ring of material of the Ring Nebula and also the central white dwarf which is all that is left of the original star. In around five billion years our sun, and the planets of the solar system, will meet the same fate when it runs out of fuel.

“Please keep a lookout towards the north during July for noctilucent clouds, which I mentioned last month. They should be quite active, especially during the first three weeks of the month.

“The noctilucent cloud season started quite early this year and I recorded the first display on May 24/25. By early June, displays had been seen as far south as Chelmsford. This is quite unusual and indicates that ice is building rapidly in the upper atmosphere. We should be able to spot NLC until early August but always after sunset.

“Mercury will be lost in the dawn twilight and will not be visible throughout July. Venus gradually draws away westwards from the sun and by mid-July rises at 2am. By the end of the month it will be bright in the east at 4.30am. Mars rises around midnight and will be in the south-east at 4am in mid-July.

“Jupiter and Saturn can both be found in the constellation of Sagittarius during July. Jupiter will be low but bright in the south-south-east at 10pm with Saturn following Jupiter by about 7º but much less bright.

“The moon will be full on the 5th, at last quarter on the 12th, new on the 20th and at first quarter on July 27.”

Frank Zwolinski, left, and the late Stanley Dack pictured at Loanhead, Abernethy. Read more at the top of the left-hand column.