Brought to you by Dr. Roy Gretton, Journal Editor of The Nottingham Astronomical Society.
Please note, the NAS new permanent venue for our main meetings on the first Thursday in the month. Nottingham Emmanuel School, Gresham Park Road, West Bridgford, Nottingham, NG2 7YF.
In Ancient times…
In ancient times the Earth was thought to be flat, and in some cultures this belief persisted through to relatively modern times. It was, for instance, the standard view in China until the seventeenth century, when European ideas began to be introduced to that part of the world. The stars were once thought to be held up on a transparent dome that revolved around the Earth. The ancient Hebrews called this dome the ‘firmament’, although how it was supported was a mystery.
One can scarcely imagine the shock to someone born in those ancient times if we could magically transport them to the present, and show them our modern conception of the Earth as little more than a grain of rock hurtling through endless space – a truly dizzying idea! Today we look up and see the stars and planets moving across the sky and know that this apparent motion is due to the rotation of the Earth; and, because the Earth is also moving around the Sun, the constellations visible in the night sky change with the seasons. In fact, each individual star rises about four minutes earlier each night, or two hours earlier each month. So, for example, the sky at 10pm in mid-February looks the same as it did at midnight in mid-January – with, of course, the exception of the Moon and planets, those ‘wandering stars’ of the ancients. One star that is most prominent in mid-winter is Sirius, the brightest star in the sky as viewed from Earth, and known from ancient times as The Dog Star.
It may seem odd to be thinking of summer heat in the depths of a British winter, but the hot days of July and August have long been known as the “dog days”. Why? Well, people have always been fascinated by the first appearance of a bright star in the east shortly before the Sun rises, and in the case of Sirius this occurs every July, heralding the start of the dog days.
For the ancient Egyptians, the first appearance of Sirius before sunrise indicated that the annual flooding of the Nile was imminent. But Sirius is properly regarded as a winter star because it is highest in our sky at midnight at the start of January, and at 10 pm as February begins. More than thirty years ago handy little book was published, aimed at amateur stargazers equipped with nothing more than a pair of binoculars or a small telescope. It has the catchy title, ‘Turn Left at Orion’. This is literally what you do if you want to find Sirius. Look to the left of Orion and lower your gaze to find a brilliant white star in the constellation of Canis Major, the Great Dog (one of Orion’s hunting dogs). Sirius often seems to be flashing blue and pink, an optical illusion probably associated with the fact that it is relatively low down in our sky, and therefore its light has to pass through a lot of turbulent atmosphere before it reaches our eyes.
The Planets in January & February
Mars, still high in the constellation of Taurus, continues to be prominent in the evenings in the late winter but, as always is the case with the Red Planet, the opportunity to see it at its biggest and brightest passes quickly. Mars was closest to the Earth in early December but by the end of February its distance from us will have doubled, so through a telescope it will appear only half as big, and surface details will be harder to pick out.
Jupiter, still bright in the evening sky, is now past its best, and will be setting at 11pm at the beginning of January and before 9pm by the end of February.
Saturn has now disappeared from the evening sky and will be passing around the far side of the Sun in mid-February.
Mercury puts in a fleeting appearance shortly before sunrise in late January and early February.
Venus, meanwhile, is an evening object setting only one hour after the Sun as January begins, but over two hours after the Sun by the end of February. Thereafter it will become more prominent as spring unfolds.
Phases of the Moon
| JAN | FEB | |
| Full Moon | 6th | 5th |
| Last Quarter | 15th | 13th |
| New Moon | 21st | 20th |
| First Quarter | 28th | 27th |
