Looking to the Skies July 2021 By Brian Davidson

I’m pleased to report that I had some success with observing the partial solar eclipse at the beginning of June. Although there was a bit of cloud cover it cleared up enough to enable me to see somewhere close to the point of greatest eclipse both through solar eclipse glasses and with a homemade pinhole camera. I was with a group of people at the time and they were quite impressed with the result from the latter. There will be another partial solar eclipse next year so for a bit of fun why not try making a pinhole camera. Easy to make with minimum materials.
 
Observing
The summer solstice is past but we still have long light evenings so the following charts represent the night sky at 11.59pm BST on the 8th of July and at 10.59pm BST on the 23rd July. To use the chart, face south at the appropriate time with the bottom of the chart towards the southern horizon and you will see the stars in the chart.

We shall focus on the jewel of the summer sky this month- The Summer Triangle. It is not a constellation but is an asterism formed by three bright stars from three separate constellations. As usual facing south and looking directly above you just before your zenith you will see a very bright star. It might be easier getting a deckchair out and lying on your back! This star is Vega and you cannot miss it because of its brilliance, it is the 3rd brightest star visible from the northern hemisphere, and it has a grouping of four fairly faint stars in the shape of a parallelogram to its bottom left hand side. Together these stars make up the compact constellation Lyra- The Lyre or Harp. Vega forms a small triangle with the top right hand star of the parallelogram and another star just to its top left. Apparently if you have good eyesight you will observe that this is a double star but closer inspection with a telescope reveals that each of these is a double star. The two pairs of stars are in orbit around each other taking hundreds of years to complete a single orbit and have become known as the celebrated Double Double
            The lighter region of the chart to the left of Vega represents the Milky Way, the star filled disc of our galaxy, and there you find a giant cross in the sky and this is the constellation Cygnus- The Swan. The bright star Deneb represents the tail of the san which is flying down the Milky Way. Cygnus is a lovely summer signpost high in the sky. The star Albireo representing the beak of the swan is another double star, beautiful to see through a telescope.
            Now from a line joining Deneb and Vega, look down about halfway to the horizon and you find another bright star Altair in the constellation Aquila- The Eagle. Altair is identified by two fainter stars either side of it forming a line pointing to Vega. The three stars Vega, Deneb and Altair form what is called the Summer Triangle depicted in red on the chart. You will enjoy looking at it for the rest of the summer and it is a great help in finding your way around the night sky.
            We’ll do that right away to find two small constellations. Contained within the Summer Triangle near the bottom vertex is the constellation Sagitta- The Arrow. It is the third smallest constellation and is somewhat dart shaped but even the brightest star at the point of the arrow is only of magnitude 3.5 so you will need dark sky conditions and a clear sky.
            To the left of Sagitta and outside the Summer Triangle is another small but distinctive constellation Delphinus- The Dolphin. The magnitude of its stars is similar to those of Sagitta so again you will need clear, dark sky conditions.

From Altair, looking southerly, drop down the Milky Way and close to the horizon is another zodiacal constellation Sagittarius- The Archer. It is hard to imagine anything that represents an archer but what is easily recognisable is the asterism- The Teapot, outlined in red in the chart. Lying as it does in the direction of the Milky Way, Sagittarius is an area of the sky rich in star clusters and bright nebulae which hide the very centre of our galaxy where there is believed to be a supermassive black hole some 26,000 light years away.
 
Something to look out for
The planets are not well placed for observing this July so why not enjoy a broad sweep of a starry summer’s evening instead. Start with The Plough and Cassiopeia, which are visible throughout the year, and notice how they have continued on their anti-clockwise journey facing each other across the North Pole with The Plough to your west and Cassiopeia to your east. Now follow the arc of the handle of The Plough down to Arcturus in Bootes as we did in May. Turn slightly east to see The Keystone of the constellation Hercules and continue on to the Summer Triangle discussed above. Take a final look to the east and see if you can pick out The Great Square of Pegasus. Then raise your eyes towards the North Pole and there you see Cassiopeia again. If that doesn’t raise your spirits on a clear summer’s evening I don’t know what will!
Clear skies.