Night Sky III

Next to the moon Venus is our most familiar night sky friend through its eye catching brilliance. Stars twinkle as point sources but planets appearing like disks twinkle less. Using a telescope you can spot the planet has phases like the moon from crescent to full. Christians will be familiar with the term ‘morning star’ linked to Venus’s visibility just before dawn. In Revelation 22:16 Christ describes himself as such giving way to God. Orthodoxy sees St John the Baptist as such and the Roman Catholic Litany of Loreto sees the Blessed Virgin Mary as such, both giving way to Christ new dawn of humanity.

It’s unsurprising that Scorpion constellation broods over the equator! Over my years in tropical and equatorial Guyana, South America I had quite a few encounters with these beasts. I even shook my shoes out every morning before putting them on for work at our Anglican seminary in Yupukari. Looking to the skies at night we easily recognised it with its unmistakable coiled tail, a sight denied us in the northern hemisphere. Though constellations are coincidences of unrelated stars you really felt there was a coherence about the Scorpion, probably the most beautiful arrangement in the Zodiac.

I love this view of earthrise seen and photographed by the astronauts privileged to travel on the Apollo 11 mission of 1969. As we look at the earth where are the national borders we fight over? How small and fragile it looks! The atmosphere is so delicate, something we’re so well aware of nowadays with the radical rebirth of the environmental movement. Above all the immensity of space in which earth takes such a little place! To the eye of faith if humans, in God’s image, can look at earth like this, what must God be like whose vision is over all?

 

Have you ever felt a star winked at you? There’s one known to do so - Algol! The bright W-shaped constellation, Cassiopeia on the opposite side of the Pole Star from the Plough or Dipper, is a guide to finding the so-called Demon star in Perseus constellation. In 1669 Italian astronomer Montanari noticed Algol, normally bright as the Pole Star, every two and a half days giving a long, slow wink over 4 hours falling in brightness by a factor of ten for 20 minutes before recovering. We now know what’s happening - Algol’s made up of two rotating stars. The wink happens when the fainter one passes in front of the brighter one.

Unless you catch it with a telescope or binoculars the Straight Wall (Rupes Recta) is less striking than on this NASA picture taken obliquely. You just don’t expect something so straight on a natural surface like the Moon, to be exact on the southeastern part of the Mare Nubium. It’s name in Latin is translated ‘straight cliff’ but it's usually known as the Straight Wall and it catches your eye in its straightness because its 110km long and 2-3km wide. As its height is only 240-300m the appearance of a vertical cliff is also just that, apparent! 

Some pictures from astronomy textbooks put us in our place - and this is one! The red pointer is the situation of our sun and planets - solar system - within our galaxy. It’s shaped like a fried egg, a flattened sphere of sun-like stars, with most stars confined to a thin disc around this, the ‘white of the egg’. The matter and stars in the galaxy are not evenly distributed but spiral out from the centre. Our sun is on the edge of one of the spirals. With the galaxy, which has a diameter of 100,000 light years, we rotate every 220 million years.

We’re aware of living with our sun in a Galaxy of such suns (stars) on really clear sky nights when we see a hazy band of light caused by stars that can’t be individually distinguished, the so-called Milky Way which contains our solar system. The Milky Way passes behind a bright W or M-shaped constellation known as Cassiopeia, the Queen, on the opposite side of the Pole Star from the Plough or Dipper. It’s all a brilliant sight through binoculars which, unlike telescopes, capture more light from the stars and over a larger area.

Astronomy helps you understand the way we live on earth. Living near the equator in tropical Guyana I knew just wet and dry seasons. Back in the UK I find life very different in summer compared to winter. Summer is a warm season here since days are longer with the Sun high up giving heat and light to the ground. Winter is cold since days are shorter, the Sun low in the sky providing less heat for us. Both the changes in length of day and Sun height are caused by the tilt of the Earth's spin axis with respect to the plane of the Earth's path around the Sun.

The bull in the sky (Taurus) is built round seeming horns, the orange-red eye of Aldebaran and the sparkling mane of the Pleiades. To find it you go to Orion’s belt and travel out with your eye in line with that to the orange star, Bull’s eye, and on to the star cluster. Taurus, second sign of the Zodiac, is a great part of the sky to scan with binoculars on account of the different colours and open star clusters. Orange Aldebaran is 100 times brighter than our own orange sun and looks a bit like Betelgeux in Orion.

I put New Moon in my diary because in the absence of the Moon you can do better stargazing! This means that week I actively prioritise viewing the night sky. With British weather about half of nights are clouded and unsuitable for astronomy in any case, not to mention long summer days which precludes observation. All of this being said the Moon catches my eye when its near to being full so that I’m reminded to ponder its features. This pondering is enhanced by binoculars but most of all by a small telescope even if you have some trouble there viewing what’s a moving object.

Celestial hippies - comets - are named from Greek as ‘the long haired ones’ streaming on rare occasion across the night sky. Comet Schomacher-Levy was discovered orbiting Jupiter in 1993 and its capture by the planet’s gravitational field meant easy prediction of its landing there. In July 1994 our family saw evidence of this landing ‘with a bang’ as two dark spots appeared on the planet visible through our telescope from the Vicarage garden at St Luke, Coventry. It was great seeing these come and go over the inside of a week and joining in many conversations with astronomers locally in consequence.

The Dog Star or Sirius is the brightest star in the sky when you can see it. It’s part of Canis Major (The Great Dog) constellation visible in the UK on the horizon below Orion from December to March. Legends talk of Canis Major as Orion’s hunting dog. Besides being brightest star in the sky, Sirius is also closest star to earth just nine light years distant. Sirius means ‘sparkling’ and appears to quickly change colour as it sparkles, blue then white, an eye catching star if ever you saw one, when it’s there to see!