Night Sky II


Once spotted in the UK autumn night sky, never forgotten - after all squares don’t have a natural feel to them! Four stars - Markab, Scheat, Algenib and Alpheratz - make up the  Great Square of Pegasus as useful as the belt of Orion for getting your bearings on the night sky. The give away is the black emptiness of the square. It’s actually not a constellation in itself but belongs partly to Andromeda and partly to Pegasus. Two stars on the square are on a straight line drawn from the Pole star to the edge of Cassiopeia constellation.

Here’s the most distant spot the human eye can see unaided. Andromeda galaxy (M31) has some hundred billion suns and is 2.2 million light years away. How can you find it? By finding the dark square of Pegasus and skipping two stars from one of the corners straining your eye to find an elliptical blur. Binoculars show it more obviously but don’t bring out the beautiful spiral shape evident in this telescope picture. It’s called the Andromeda nebula on account of its haziness but when you look at it, your mind gets mightily focussed at the thought of its unthinkable distance from us!

Ever seen a reversed question mark in the night sky? As if a query of us from God! The dot in it is Regulus, brightest star in Leo the lion, fifth sign of the Zodiac or circle of animals across the night sky. This belt of twelve constellations has at its centre the ‘ecliptic’, an imaginary line along which the sun, moon and planets travel across the year. How do you find Leo? Spot the Pole Star and move your eye to the Plough and beyond. It’s visible in the UK’s night sky from February to June. 

Brooke Bond PG Tips first got me into astronomy by collecting their free ‘Out into Space’ picture cards from tea cartons and sticking them in their 6d (2.5p) booklet. Here’s the first page of my completed booklet with my 1960 signature at the top. It’s got tracings of the animals people have identified in the night sky, some known as signs of the Zodiac. As earth rotates the sky containing its stars swings overhead from east to west every 23hr 56min so you lose some constellations as others appear. The 4min shortfall means the constellations creep across your view in a year if you observe the same time every night.

There’s always excitement in the night sky even if most lights up there are fixed in relation to the rest. The planets are literally ‘wanderers’ though they wander on a predictable path, same as the sun and moon, the so-called ‘ecliptic’ path. The five brightest planets - Mercury, Venus, Mars, Jupiter and Saturn - can easily be seen with the naked eye if you know when and where to look. My PG Tips picture cards illustrate the relative size and number of moons of our sun’s planets as well as the asteroid or minor planet belt. The ring between Mars and Jupiter has planets from a few miles up to 480 miles diameter.

When we see two adjacent bright stars it’s always a coincidence. They look close, but it’s looks alone. Most famous of such duos are the so-called Heavenly Twins, Castor and Pollux, a sign of the Zodiac. Astronomical research shows Castor is 46 light years away from earth in contrast to Pollux only 36 light years away. Furthermore Castor is a binary or double star whereas Pollux, a single star, has an unmistakable orange colour. The Twins, Gemini, are easily found in the perimeter of the major Orion constellation. In the past Pollux appeared fainter, now it looks brighter than Pollux. 

My knowledge of the moon comes from both telescope and binocular observation day by day, month by month, and what a fascinating hobby it is. If only you’ve time to look up, stand (or sit) and stare! The diagram distinguishes four features: craters, rayed craters, mountains and seas. Copernicus and Tycho shine forth with their rays at full moon, displaying a record of the impact that formed them eroded elsewhere. The mountain ranges are displayed as the lit bit of the moon changes day by day. The seas are so-called as once thought to hold water. The first manned moon landing by Armstrong and Aldrin was on the dry land of Tranquillity Sea in July 1969.

Few parts of the world miss Orion’s regular dominance of the night sky. Undoubtedly the most glorious constellation visible from UK latitude, it’s an excellent reference point apart from when it's below the horizon. The Greeks saw demigod Orion as a powerful hunter squabbled over by goddesses. For ancient Egyptians he was Osiris, God of light. Aboriginal Maoris in New Zealand see the constellation as a canoe. Guyanese Amerindians see him as a Powis hunter since the star arrangement seems to pursue bird star forms. Some Brazilian Indians see Orion as an alligator. Through human history the constellation has provoked awesome contemplation.

When I worked among Amerindians in Guyana my street rating soared when I predicted an eclipse from my Astronomy magazine . Living in the rainforest with people so close to nature we were infected by deep reverence for creation. The brief disappearance of moon or sun seemed to contradict the order their regular movements are associated with. The diagram is a logical explanation of the eclipse of the moon when covered by the earth’s shadow. The caption mentions the refraction of sunbeams which enhance dawn and dusk as well as making the moon copper coloured at a lunar eclipse.

Can you spot the Plough feature on the left of this diagram of Ursa Major? Also known as the Big Dipper most of this feature is part of the Great Bear constellation. Following the two plough or dipper end stars, joined by a dashed line, upwards you reach the north or pole star. In the Greek myth Hera was furious when her husband Zeus fell in love with Callisto so she changed her rival into a bear. Callisto - now a bear - wandered the forest in terror of the other animals until Zeus placed her safe in the stars.

How fascinating the Moon is! Even if we amateur’s can’t get as good a picture as this we get a sense of the detail from its large features and from following the ‘terminator’ ie light/dark sunshine divide across the month. These ridges and craters are on the Mare Imbrium near Copernicus crater. You can see two or three crater chains which imply formation at the same time, either from landing space debris or past volcanic activity, which is most likely responsible for the ridges or ridge-like protrusions on the Moon.

Living for some years in the rainforest of Guyana near the Brazilian border 4 degrees above the equator guaranteed seeing stars I’d never seen before. With no electricity you saw a lot more stars because after sundown they were a free diversion if the night was clear, as it usually was. The first missionaries saw a Cross in the sky and named it the Southern Cross as the vertical points south. It’s the smallest of all constellations but prominent in a star bare section of the night sky with two adjoining stars, Alpha and Beta Centauri, the latter nearest to earth of all bright stars.

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