Archive for January, 2010

Our winter almanac 29.01.2010 – 04.02.2010

Posted in astronomical time on January 29, 2010 by espacelab

February begins, named after Februa, the Roman Festival of purification.

Look out early on February evenings for a couple of brilliant stars, Rigel in the foot of Orion and Capella in Auriga.

Special Numbers
Last week our almanac featured the star chart and the way they are usually designed as a circular map, and marked by latitude and longitude in degrees and minutes. The origins of degrees and minutes lies with ancient Sumerians.

The ‘degree’ was devised by the ancient Sumerians of the middle-east. It was they who divided the circle into 360 degrees. Their word for a degree was ‘gesh’ which meant man, or one, or one degree.

The Sumerians of ancient Mesopotamia (2100 BC) had a calendar of 360 days. This came from rounding off the lunar month of 28 days to 30 days. Our almanac will explain more about what a lunar month in a future post.

This number of 360 fitted their mathematical and astronomical system that was based on the numbers 6 and 60.

Multiplying 6 x 60 equals 360, and 360 is the number we still use to divide the sky and any circular plane, and to this very day we divide all circles into 360 degrees.

The number 60 is also important for us and our astronomical clock because clock faces are usually divided into the familiar 60 units that we use to mark both minutes and seconds.

The word ‘second’ comes from the Latin secunda, meaning ‘second’ as in coming after the first, and being a shorter way of saying “secunda minuta”, or the second minute that comes after the first minute.

There has been lots of speculation as to why the number 60 was so important to the Sumerians. The fourth-century Greek scholar Theon supposed that the reason 60 was chosen as the base number for their numbering system was that 60 was the lowest number into which their first 6 numbers divided. Even with our number system you can see that 60 divides by 1, 2, 3, 4, 5, 6, 10, 12, 15, 20 and 30!

The Sumerian gods were given numbers. Anu, the great god of the heavens was given the number 60, Anatu, the earth-god has the number 50, Abyss is given 40, the moon-god is 30, and the sun-god is given 20. As we have noted already, the Sumerian word for 1 is the same word as is used for ‘man’.

For the Sumerians, the most mystical number of all was 60 x 60, which comes to 3,600. This number was called ‘sas’, a word that means ‘everything’, ‘whole’ and ‘cosmos’. The Sumerian written symbol for this word looks a bit like a circle!

Perseus is the Constellation Logo for Oakridge School.

Perseus is one of the most important figures of ancient Greek mythology and the legendary founder of Mycenae and of the Perseid dynasty there. He was the first of the mythic heroes of Greek mythology whose exploits in defeating various monsters left over from the mythic beginning of the world. Perseus was the hero who killed Medusa and claimed Andromeda, having rescued her from a sea monster.

In the constellation of Perseus it his bravery in killing the gorgon Medusa that is drawn out in the sky amongst the stars.

The star called Algol may not be the brightest star of this constellation, but it definitely is its most famous star. Algol (from Arabic al-Ghul, which means The Ghoul or The Demon Star) represents the eye of the gorgon Medusa. This star is the prototype of a whole group of eclipsing variable stars.

The first variable star was identified in 1638 when Johannes Holwarda noticed that Omicron Ceti (later named Mira) pulsated in a cycle taking 11 months. The second to be described variable star was the eclipsing variable Algol by Geminiano Montanari in 1669; John Goodricke in 1784 gave an explanation of its variability. Until relatively recently Algol was understood to be an eclipsing binary star is a binary star in which the orbit plane of the two stars lies so nearly in the line of sight of the observer that the stars eclipse each other so it looks like a blinking star. However Algol turns out to be a multiple star, a ternary star with three stars forming a star system

Cross roads and pedestrian underpass in Oakridge on a winter day 05.02.2010


Our winter almanac 22.01.2010-28.01.2010

Posted in astronomical time on January 22, 2010 by espacelab

Star Charts

Looking near the Meridian at about 20h you can find the constellations Auriga, Perseus, Orion and Taurus. Most star charts of the night sky are designed as a circular map, and marked by latitude and longitude in degrees and minutes, just like the maps of the Earth’s surface.

This was the Constellation Logo for Beech Down School at Brighton Hill.

A new constellation – the kite
Sadly, Beech Down School is no more, having been closed after a catastrophic fire during November 2000. One of the Beech Down school pupils came up with a brilliant modern version for the Constellation Auriga – a beautiful kite!

Auriga is a constellation in the northern sky. Its name is Latin for ‘charioteer’ and its stars form a shape that has been associated with the pointed helmet of a charioteer. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and is included among the 88 modern constellations. Its brightest star is Capella.

According to one Greek myth, Auriga represents Hephaestus, the blacksmith god, who was lame and invented the chariot so as to easily travel wherever he wanted. In another Greek myth, Auriga is said to represent Myrtilus, the charioteer of King Oenomaus, and who sabotaged the king’s chariot.

Auriga is also identified as the mythological Greek hero Erichthonius of Athens, the chthonic (an “Earth deity”, or a spirit of the soil with all its power to create growth out of the ground) son of Hephaestus who was raised by the goddess Athena. According to the anonymous writer of the composition Catasterisimi, Erichthonius was generally credited to be the inventor of the quadriga, the four-horse chariot, which he used in the battle against the usurper Amphictyon that made Erichthonius the king of Athens. Erichthonius then dedicated himself to Athena and soon after, Zeus raised the Athenian hero into the night sky in honor of his ingeniuity and heroic deeds.

Ancient mythology and the night sky seem to go together like a horse and chariot!

Beech Down on a grey day! 28.01.2010

Our winter almanac 15.01.2010-21.01.2010

Posted in astronomical time on January 15, 2010 by espacelab

Solar eclipse

Solar annular eclipse of January 15, 2010 in Bangui, Central African Republic

The solar eclipse of January 15, 2010 was an annular eclipse of the Sun with a magnitude of 0.9190. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partially obscuring Earth’s view of the Sun. An annular solar eclipse occurs when the Moon’s apparent diameter is smaller than the Sun, causing the sun to look like an annulus (ring), blocking most of the Sun’s light. An annular eclipse appears as a partial eclipse over a region thousands of kilometres wide.

It was the longest annular solar eclipse of the millennium, and the longest until December 23, 3043, with a maximum length of 11 mins and 7.8 seconds. (The solar eclipse of January 4, 1992 was longer, at 11 minutes, 41 seconds, occurring in the middle of the Pacific Ocean.)

The eclipse was visible as only partial eclipse in much of Africa, Eastern Europe, the Middle East and Asia. It was seen as annular eclipse within a narrow stretch of 300 km (190 mi) width across Central Africa, Maldives, South Kerala (India), South Tamil Nadu (India), Sri Lanka and parts of Bangladesh, Burma and China.

The Winter Circle

It was the invention of mechanical clocks about 650 years ago that made it possible for medieval monks in their monasteries to accurately measure out the 24 hours of the day, using a clockface that marked out the 12 hours before noon and the 12 hours after noon. They used these amazing new inventions to help them say their prayers and conduct their daily services at precise times of day and night. These times, and the hours of the day had always been marked by the ringing of bells, and the word ‘clock’ comes the German word for bell, ‘glocke’.

This week we are including a diagram of the winter constellations to help you find your way around the night sky at this time of year.

The diagram shows what is sometimes called the ‘winter circle’, but we have marked it out like a clock, so that you can find the brightest star in the night sky, Sirius in the constellation Canis Major, in the 6 o’ clock position.

In the middle of the circle you can find the red star Betelgeuse forming part of the constellation of Orion. Orion is always an easy constellation to find at this time of year. Orion the Hunter has a belt formed of three bright stars which point towards the constellation of his faithful dog Canis Major.

At nearly the 12 o’ clock position is the bright star Capella which is part of the constellation of Auriga, the Charioteer. Just above the 9 o’ clock position you will find the constellation of Gemini the Twins, with two bright stars , Castor and Pollux. Just below 9 o’ clock you will find Canis Minor the Little Dog.

The clock face image helps us find our way around the sky at night as well as telling us the time.

Orion was the Constellation Logo for Winklebury School.

Orion, often referred to as “The Hunter,” is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the largest, most conspicuous, and most recognizable constellations in the night sky.

The current configuration of stars now known as the constellation of Orion roughly formed about 1.5 million years ago, as stars move relatively slowly from the perspective of Earth. Orion will remain recognisable in the night sky for the next 1 to 2 million years, making it one of the longest observable constellations, parallel to the rise of human civilization.

Because they are so bright and distinctive, the pattern of stars that forms Orion was recognized as a coherent constellation by many ancient civilizations, though with different representations and mythologies.

One of Winklebury’s students came up with this great new version of a constellation identity; a water rollercoaster!

Another bit of snow melting in Winklebury 21.01.2010

The Hindu Festival of Vasant Panchami takes place on Wednesday 20th January and is dedicated to Saraswati, the goddess of learning and Brahma‘s wife. Even though for the inhabitants of Basingstoke it is still Winter, the festival marks the beginning of Spring.

Our winter almanac 08.01.2010-14.01.2010

Posted in astronomical time on January 8, 2010 by espacelab

14.01.2010 is the Hindu Festival of Makar Sankrant also known as Lohri in Punjab, Kicheri in Uttar Pradesh, and known as Pongal, the 3 day harvest festival, in Southern India.

The festival is one of the most important festivals of the Hindu calendar and celebrates the sun’s journey into the northern hemisphere, a period which is considered to be highly auspicious.

In Gujarat and Maharashtra, Makar Sankrant is a festival of the young and the old. Colourful kites are flown all around.

Changing Places
January is the first month of our year 2010, named after the Roman god of the gateway, Janus. Janus had two faces, one face with eyes looking forward to the new year and the other face looking back to the old.

In England the new year has not always begun on the 1st January. Over a thousand years ago it was Christmas Day that marked a new Year. Then about 800 years ago the first day of the year was changed to the feast of the Annunciation of the Blessed Virgin, or Lady Day, on March 25. This was the beginning of the legal, or civil year until 1751 when the date was changed again to begin the next year on January 1 1752.

While people are free to change their minds over the days and dates of the calendar, the stars in the night sky remain in the positions they have occupied for thousands of years.

To see any change in the position of the stars, and the patterns they make in the night sky, you would have to travel 100,000 years in time. This means that the ancient people who gave these constellations the names we use today, would recognize the astronomical scene we see this week as made from the winter constellations. They would have recognized Orion the Hunter, just as we do now, with his belt made from three bright stars, well up in the north eastern sky by 20.00h.

The Dog Star

Looking at the night sky at this time of year, in a place where there are no street lights to make the stars difficult to see, it will be possible to see the winter Milky Way. This is an entirely different view of our home galaxy than we will see in the summer. This is because during the night at this time of year we look out to the edge of our galaxy into deepest space, while in summer we look towards the centre of the galaxy, obscured by vast clouds of interstellar dust.

Astronomers have identified two specific spiral arms that stretch out to the edge of our galaxy, and it is these structures of stars, and the dust and gas that gives rise to new stars, we see in the winter Milky Way.

A typical spiral galaxy like the Milky Way in the constellation Coma Berenices, is about 17,000 parsecs in diameter and approximately 20 million parsecs distant. The parsec (parallax of one arcsecond; symbol: pc) is a unit of length, equal to just under 31 trillion kilometres (about 19 trillion miles), or about 3.26 light-years.

Looking for bright stars
Between 21.00hrs and 22.00hrs GMT look for the Milky Way high in the sky. Then run your eye from the zenith toward the south-south eastern horizon and you might be able to see eight bright stars.

Look out for Sirius, the ‘Dog Star’, the brightest star in the constellation Canis Major, the Greater Dog, and the brightest star in the night sky. This star has been responsible for a lot of people thinking they have seen an unidentified flying object, or UFO. The brightness of the star and its position quite low down in the night sky causes some optical effects produced by the Earth’s atmosphere, including colour shifts and movement, and a feeling that this star is much closer than it actually is.

In fact, Sirius is 51 trillion miles from Earth, making this star a near neighbour of ours and the fifth nearest star to our Sun.

One of the pupils at South View came up with a modern version for the Constellation Logo for their school. Pizza!

The thaw begins in South View 14.01.2010

Our winter almanac 01.01.2010 – 07.01.2010

Posted in astronomical time on January 1, 2010 by espacelab

In this first post for 2010 we will look at how the Sun and the Winter Solstice set the beginning of the astronomical season of winter and our astronomical time

The beginning of winter and the start of our Astroclock winter almanac 2009-2010 is marked by the coming of the winter solstice. This took place on December 21 2009.

In our part of the world, in what is called the northern hemisphere, the winter solstice is the time when the Sun reaches its southernmost point from the celestial equator. For people living in the southern half of our planet, in places like Australia, Africa and South America, this day of our winter solstice is their summer solstice, because the Sun is shining directly over the southern tropical latitude.

The Earth spins on its axis every 24 hours, giving us our 24 hours and night and day, but this axis has got a tilt of 23.4 degrees. It is this tilt that causes the seasonal changes we see over the 12 months of the year. For instance, on the date of the winter solstice the northern half of our planet is tilted away from the Sun at the full angle of 23.4 degrees, so that sunlight reaching us is not so strong as it is on the summer solstice when our part of the planet is tilted fully towards the Sun.

Over 4,000 years ago, people who lived in our part of southern England used large standing stones to accurately measure out the length of the year from solstice to solstice. The point on the horizon where the rising Sun would appear would be marked using these standing stones. When the Sun rose again at this point 365 days later, these people could tell that a year had passed between the solstices. This was an astronomical measurement. At Stonehenge, not far from Basingstoke, the stones still frame the point on the horizon where the sun sets on the winter solstice.

These days, with our very accurate clocks we can measure the year exactly. For instance, the time between the winter solstice of 1999 and the winter solstice of the year 2000 was 365.24274 days. Even though the ancient people living here 4000 years ago could mark the year, they had no clocks to measure time accurately, or any use for hours, minutes and seconds.

The New Year

In the middle of this second week of our astronomical winter almanac we will celebrate the arrival of a new year.

The year 2010 celebrations mark the time since the year of Christ’s birth, even though many people think Christ was born 2006 years ago in the reign of King Herod.

The calendar that makes this year the year 2010 was devised many centuries ago by a man called Dionysius Exiguus, which means ‘Little Dennis’. He was a brilliant scholar, mathematician and astronomer. In the year 525AD, Pope John I asked Dionysius to calculate the date for Easter for the following year 526AD.

When he had completed his work calculating the date of Easter for the next 95 years Dionysius also invented a system of dating known as anno Domini, or AD. This is the latin for ‘the year of our Lord’.

In the year we now call 531 AD, when Dionysius created this system, the number of the year was 247 anno Diocletiani, the year of the Roman Emperor Diocletian, a notorious persecutor of Christians. So Dionysius counted back the years to the year he believed Christ was born, and gave this year the number 1, preferring a Christian beginning to the numbers of the years.

Beginning with One or Zero

Dionysius wasn’t able to make the year of Christ’s birth AD 0, because the idea and symbol for zero had not yet been introduced into the European lands. So, some people say that because Dionysius began his calendar with the year 1, all the special celebrations during the so called millennium year of 2000 were in fact happening in the last year of the twentieth century and the very last year of the second millennium.

Christmas in January!!!!!
Wednesday 6th January is a Christmas Day (Armenian Orthodox)!
Armenian Christians celebrate Christ’s birth at Epiphany, except for Armenians in the Holy Land, who celebrate Christmas on January 19th. Theophany (Orthodox), Orthodox churches mark the baptism of Jesus on this day. Epiphany celebrates the visit of the wise men (the magi) to the infant Jesus. In the East, where it originated, the Epiphany celebrates the baptism of Jesus by John the Baptist in the River Jordan. (Catholics and Episcopalians celebrate this separately: see Baptism of the Lord) Also known as Dia de los Reyes (Three Kings Day).

Thursday 7th January is Christmas Day for Orthodox Christians. Most Orthodox churches use the Julian rather than the Gregorian version of the Western calendar(more about this in future posts and pages). As a result, they celebrate Christmas 13 days later than other Christian churches.

Fairfields School 07.01.2010

From the Winter Solstice the days get longer but the weather gets colder and more wintry over the next couple of months. This is because the rate of heating of our part of the planet’s atmosphere from the Sun’s rays is offset by the rate of cooling and the reflection of heat from the planet’s surface.

Photo of a part of the sky during a meteor shower over an extended exposure time. The meteors have actually occurred several seconds to several minutes apart.

Shooting stars

The first meteor shower of the year takes place this week between January 1 – 4. The best show of these shooting stars will be on the January 3. Look out for them in the area of the night sky where you can see Bootes the Herdsman. These meteors are called the Quadrantids because they appear in the part of the night sky where a rather faint constellation looks a bit like a navigators quadrant.

Boötes the Herdsman was the Fairfields School Astroclock Logo. Exactly whom Boötes is supposed to represent is not clear. According to one version, he was a ploughman who drove the oxen in the constellation Ursa Major using his two dogs Chara and Asterion (from the constellation Canes Venatici). The oxen were tied to the polar axis and so the action of Boötes kept the heavens in constant rotation.

Finding your way around the night sky

A planisphere is very useful in finding your way around the stars and constellations of the night sky. A planisphere is a star chart analog computing instrument in the form of two adjustable disks that rotate on a common pivot. It can be adjusted to display the visible stars for any time and date. It is an instrument to assist in learning how to recognize stars and constellations.