Archive for June, 2010

Our summer almanac 18.06.2010 – 24.06.2010

Posted in astronomical time on June 18, 2010 by espacelab

Sunrise, Sunset and the view from Earth

Sunrise and sunset times vary throughout the year. Days get longer from the winter solstice to the summer solstice. Then, just as astronomical summer begins, the days get shorter and the nights become longer.

Spring turns to Summer


The Longest Day
This week sees the summer solstice on June 21 at 11.28 UTC. Coordinated Universal Time (UTC) is a time standard based on International Atomic Time (TAI) with leap seconds added at irregular intervals to compensate for the Earth’s slowing rotation. Leap seconds are used to allow UTC to closely track UT1, which is mean solar time at the Royal Observatory, Greenwich. UT1 is the principal form of Universal Time.

This is the longest day of the year and the beginning of the astronomical season of summer. The Sun rises to the north east of Basingstoke at about 03h 47m in the morning and sets at about 20h 25m in the evening in the north west. These times are GMT, so the local time of British Summer Time means that you need to add ONE hour to these times to see sunrise and sunset. Greenwich Mean Time (GMT) is a term originally referring to mean solar time at the Royal Observatory in Greenwich, London. It is commonly used in practice to refer to Coordinated Universal Time (UTC) when this is viewed as a time zone, especially by bodies connected with the United Kingdom, such as the BBC World Service, the Royal Navy, the Met Office and others, although strictly UTC is an atomic time scale which only approximates GMT with a tolerance of 0.9 second.

At noon on the summer solstice the Sun reaches its highest point in our sky. Noon is 13h Local Time because in the UK, GMT is the official time only during winter; during summer British Summer Time is used. GMT is substantially equivalent to Western European Time.. From the spring equinox until the summer solstice the Sun moves northwards day by day. The Sun does not move northwards at the same rate of speed. At the beginning of spring the Sun moves very quickly north. At the summer solstice this rate of speed slows, like the swing of a pendulum at its limit. This means that this week the Sun seems to rise in almost the same place on the horizon. This is why we use the word solstice for this special day, as it comes from a Latin word “solstitium” meaning “Sun stands still”.

Stonehenge

Basingstoke is located on the old road (now called the A30 and that then turns into the A303) that runs to the west country and passes the ancient monument of Stonehenge.

The standing stones surrounding Stonehenge mark the point on the horizon where the sunrise takes place on the summer solstice. However, the special celebrations that take place upon the summer solstice these days were not the main event at Stonehenge 5000 years ago.

The diagram above shows how the Stonehenge monument has in recent years been interpreted as an astronomical design. It shows the direction of the sunrise on the summer solstice and the orientation of the stones. The most recent theory is that it is the orientation of the monument to the setting sun at the winter solstice that accounts for the arrangement of stones on this ancient site that has been used going back to at least 8000 years ago.

Recent archaeological investigations have shifted the emphasis from thinking about Stonehenge as either an astronomical device, or a temple of the dead but not forgotten ancestors, to the rings of bluestones that were brought all the way from Wales. The bluestones at Stonehenge were placed there during the third phase of construction at Stonehenge around 2300 BC. It is assumed that there were about 80 of them originally, but this has never been proven since only 43 remain.

The majority of them are believed to have been brought from the Preseli Hills (over 160 miles from Stonehenge) through our ancient ancestors organizing their transportation. How they achieved this is a mystery, but the most likely theory is they were brought by raft navigating along the coast of Wales and then pulled upstream along the River Avon. This would have been the most ambitious logistics project ever attempted by humans.

The bluestones were associated with the healing power of sacred springs. One very recent theory that has been supported by the most recent archaeological investigation at Stonehenge is that the bluestones were at the heart of the reason for the monument; healing power. The people who made Stonehenge were able to do so because they lived a whole way of life around the seasons of growing and harvesting in the ancient farming calendar. Mid-winter, the winter solstice was the beginning of the new year of growth, fertility and food production.

Calculating the time in Basingstoke

The clock on St Michael’s Church Basingstoke shows 1pm, but this is in fact midday when it comes to Greenwich Mean Time (GMT) because we are now in British Summer Time. In the UK, GMT is the official time only during winter; during summer British Summer Time is used.

Greenwich Mean Time is set for the world in Greenwich at the Greenwich Royal Observatory when the the sun reaches the highest point in the sky at noon.

GMT became the UK’s official time with the coming of the railways and the railway timetables in the 19th century.

Before the age of railways each town would set its clocks to local time, using a sundial to find out when it was the sun was at its highest in the sky.

The sundial on St Michael’s Church shows noon.

So why is the clock showing just over 4 minutes past the hour? Because Basingstoke is just over 4 minutes longitude west of Greenwich!



Canis Minor is a small constellation containing only two bright stars, Procyon and Gomeisa. Procyon is the eighth brightest star in the night sky. Procyon means “before the dog” in Greek, as it rises an hour before the ‘Dog Star’, Sirius, of Canis Major. Canis Minor has no deep sky object brighter than magnitude 15.

Near Chalk Ridge School 24.06.2010

Our spring almanac 11.06.2010 – 17.06.2010

Posted in astronomical time on June 11, 2010 by espacelab

The World Cup opens in South Africa 11.06.2010


The first two World Cup matches took place in Uruguay, simultaneously on 13 July 1930, and were won by France and USA, who defeated Mexico 4–1 and Belgium 3–0 respectively. The first goal in World Cup history was scored by Lucien Laurent of France. In the final, Uruguay defeated Argentina 4–2 in front of a crowd of 93,000 people in Montevideo, and in doing so became the first nation to win the World Cup. The FIFA championship has been awarded every four years since the first tournament in 1930, except in 1942 and 1946 when it was not contested because of World War II.

Night skies in Taurus

The Pleiades

The Pleiades, or Seven Sisters (Messier object 45), is an open star cluster containing middle-aged hot B-type stars you can see in the constellation of Taurus.

An image of the Pleiades in infrared light, showing the associated dust.

X-ray images of the Pleiades reveal the stars with the hottest atmospheres. Green squares indicate the seven optically brightest stars.

Pleiades is among the closest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky, and so the fact that people looking at the night sky over thousands of years leads to the Pleiades having many different associations among different cultures and traditions.

This disk is attributed to a site near Nebra, Saxony-Anhalt in Germany, and associatively dated to c. 1600 BC. It has been associated with the Bronze Age Unetice culture. The Nebra Sky Disk as it is called, is a bronze disk of around 30 cm diameter, with a blue-green patina and inlaid with gold symbols. These are thought to show the sun or full moon, a lunar crescent, and stars, including a cluster that could well be the Pleiades.

The Pleiades Πληιόνης (pleye’-a-deez, also plee’-a-deez), companions of Artemis (ar’-te-mis), were the seven daughters of the Titan Atlas (at’-las) and the sea-nymph Pleione (pleye-oh’-nee) born on Mt. Cyllene (seye-lee’-nee). They are the sisters of Calypso, Hyas, the Hyades, and the Hesperides.

Navigation and the Pleiades
There is some debate as to the origin of the name Pleiades. Previously, it was accepted the name is derived from the name of their mother, Pleione. However, the name Pleiades is more likely to come from πλει̂ν (to sail), because the Pleiades star cluster are visible in the Mediterranean at night during the summer, from the middle of May until the beginning of November, which coincided with the sailing season in antiquity. This derivation was recognized by the Roman poet Virgil (Georgics 1.136-138).

The Greek poet Hesiod mentions the Pleiades several times in his Works and Days. As the Pleiades are primarily summer stars, they feature prominently in the ancient agricultural calendar. Here is a bit of advice from Hesiod:

“And if longing seizes you for sailing the stormy seas,
when the Pleiades flee mighty Orion
and plunge into the misty deep
and all the gusty winds are raging,
then do not keep your ship on the wine-dark sea
but, as I bid you, remember to work the land.”

The Minoan Civilization
The Minoan civilization, a Bronze Age civilization, arose on the island of Crete, the largest island in the part of the Mediterranean known as the Aegean Sea.

It is one of the oldest civilizations and flourished from approximately the 27th century BC to the 15th century BC. This was a time so ancient that the ancient Greeks remembered it only in stories and mythology. It was rediscovered at the beginning of the 20th century through the work of the British archaeologist Sir Arthur Evans.

It was a civilization based on trade across the Mediterranean, including Egypt. This trade depended on the ships and sailors who sailed them. Navigation and sailing makes for trade, wealth and communication.


The Phaistos Disc is a disk of fired clay from the Minoan palace of Phaistos, possibly dating to the middle or late Minoan Bronze Age (2nd millennium BC). The disc was discovered in 1908 by the Italian archaeologist Luigi Pernier in the Minoan palace of Phaistos, on the south coast of Crete, and features 241 tokens, comprising 45 unique signs, which were apparently made by pressing pre-formed hieroglyphic “seals” into a disc of soft clay, in a clockwise sequence spiraling towards the disc’s center. On side A of the disc one can find twice the depiction of a pigeon.

In Ancient Greek mythology doves stood for the constellation of the Pleiades. In Hesiod’s Astronomy the Pleiades are called doves. The interval between two depictions of the sign pigeon on side A (signs 45 and 91 from the beginning of the inscription) is 46 signs which approximately corresponds to the number of days between the evening disappearance and the morning appearance of the Pleiades. The observation of the vernal disappearance and appearance of the Pleiades was very important for early Greek astronomy and was described in Hesiod’s Works and Days.

The west wind Zephyr as in the “Spring” of Sandro Boticelli.

If the Pleiades rising and setting are 25 March and 10 May, the beginning of calendrical count on the Disk will be 8 February. It is beginning of the month of Aquarius close to the early spring (when the western wind blows) in Greek calendars and considered to be the spring herald.

It may well be that the Phaistos Disk is a star compass that resembles star compasses of Arabian and Polynesian sailors but is not identical to them. Each field of the Disk contains information about the constellations whose brightest stars are arranged along the East-West line on appropriate days (beginning with 8 February). For example, the field A1 contains five signs which correspond to the period from 8 February to 12 February. In this period on the East-West line one can observe some of the brightest stars of the constellation of Cancer (Ancient Greek Karkinos = the sign no. 2 karekomoontes ‘long-haired’ on the Phaistos Disk), Capella (Ancient Greek Aix = the sign no. 12 aigis ‘shield’ on the Phaistos Disk), Perseus (see above), Andromeda (see above), and Sextans (see above) in the first minutes of their visibility after the sunset. Some fields contain the constellations in the last minutes of their visibility before the sunrise, e.g. the field A23 describes the first morning rising of the Pleiades. In several cases a field might contain information both on the morning and evening constellations.

The Hayabusa (はやぶさ?, literally peregrine falcon) returns to Earth 03.06.2010

An unmanned spacecraft developed by the Japan Aerospace Exploration Agency to return a sample of material from a small near-Earth asteroid named 25143 Itokawa, returned to Earth on 13 June 2010 allowing scientists to analyse the dust and therefore help us understand better how the Solar system has evolved and developed over 4.5 billion years.

The Hayabusa was launched on 9 May 2003 and reached Itokawa in mid-September 2005. After arriving at Itokawa, Hayabusa studied the asteroid’s shape, spin, topography, colour, composition, density, and history. In November 2005, it landed on the asteroid and attempted to collect samples but it is not clear whether the sampling mechanism worked as intended. Nevertheless, there is a high probability that some dust was trapped in the sampling chamber during contact with the asteroid, so the chamber was sealed, and the spacecraft made the long journey back to Earth.

The reentry capsule and the spacecraft made a spectacular return entry to the Earth’s atmosphere on 13 June, 2010 at 13:51 UTC. The heat-shielded capsule made a parachute landing in the South Australian outback while the spacecraft broke up and burned in a large fireball.

Dragon Boat Festival 16.06.2010

All over the world people chinese communities celebrate the Dragon Boat Festival. It is in fact the Duanwu Festival (Chinese: 端午節), but is also known around the world as the Dragon Boat Festival, a traditional holiday for Chinese and other East Asian and Southeast Asian societies as well. The festival occurs on the fifth day of the fifth month of the lunar calendar on which the Chinese calendar is based. This is the source of the alternative name of Double Fifth. Last year this occurred on May 28 and in 2010 it happens on June 16.

The focus of the celebrations includes eating the rice dumpling zongzi, and racing dragon boats.

Our spring almanac 04.05.2010 -10.05.2010

Posted in astronomical time on June 4, 2010 by espacelab

Flaming June


The Roman poet Ovid provides two etymologies for June’s name in his poem concerning the months entitled the Fasti. The first is that the month is named after the Roman goddess Juno, wife of Jupiter and equivalent to the Greek goddess Hera, whilst the second is that the name comes from the Latin word iuniores, meaning “younger ones“. The poem is based on the Roman calendar or Fasti, loosely following the Works and Days by ancient Greek poet Hesiod. Each of its separate books discusses one month of the Roman calendar, beginning with January. It contains some brief astronomical notes, but its more significant portions discuss the religious festivals of the Roman religion, the rites performed upon them, and their mythological explanations. These explanations preserve much mythological and religious lore that would have otherwise been lost.

The poem was written to illustrate the Fasti, or almanac and official calendar, published by Julius Caesar after he remodelled the Roman year. In the year 46 BC Julius Caesar ordered that a new calendar be devised, made of 365 and a quarter days. The fraction of a day would be counted once every four years in a leap year of 366 days, followed by 3 years of 365 days. This calendar began on the Kalends of Januarius in the year 46 BC.

In the year 10 BC the first Roman Emperor Augustus celebrated his victory over the Egyptian Queen Cleopatra with the creation of a giant public sundial. A 50 foot stone obelisk brought from Egypt was placed in the Campus Martius in the middle of an enormous grid of lines showing the length of hours, days and months, and the signs of the zodiac, and a version of Caesar’s calendar carved in stone.

The obelisk still casts a shadow across the Piazza del Popolo in modern Rome.

Gnomon
There is a special name for something people use to tell the time by casting a shadow of the Sun on a sundial, it is called a “gnomon”. If you use a sundial in Basingstoke to set noon in Basingstoke you will find our astroclock is accurate when it comes to Basingstoke time at Greenwich Mean Time minus 4 minutes and 20 seconds.

The World Cup is going to be played in winter!

June in the Northern Hemisphere is the seasonal equivalent to December in the Southern Hemisphere and vice versa. This football teams preparing for the World Cup in South Africa will be playing in South Africa’s midwinter. The month of June—in the Northern Hemisphere—is in spring until the 21st, when the first day of summer begins.

The June birth flower is the rose, or the honeysuckle, as roses and honeysuckles bloom throughout June. June is also sometimes called the “Rose month.”

Night skies in Perseus


Deep sky objects in Perseus
The Double Cluster is the common name for the naked-eye open clusters NGC 884 and NGC 869, which are close together in the constellation Perseus.

Messier 34 (also known as M 34 or NGC 1039) is an open cluster in the constellation Perseus. It was probably discovered by Giovanni Batista Hodierna before 1654 and included by Charles Messier in his catalog of comet-like objects in 1764. Messier described it as, “A cluster of small stars a little below the parallel of γ (Andromendae). In an ordinary telescope of 3 feet one can distinguish the stars.”

The Little Dumbbell Nebula, also known as Messier 76, NGC 650/651, the Barbell Nebula, or the Cork Nebula, is a planetary nebula in the constellation Perseus.

The term planetary nebula comes from the fact that this name originated with their first discovery in the 18th century because of their similarity in appearance to giant planets when viewed through small optical telescopes. We can now see that deep sky objects like this are in fact a nebula, or emission nebula, a cloud of ionized gas emitting light of various colors. The most common source of ionization is high-energy photons emitted from a nearby hot star. The Little Dumbbell Nebula derives its common name from its resemblance to the Dumbbell Nebula. It was discovered by Pierre Méchain in 1780 and included in Charles Messier’s catalog of comet-like objects as number 76. It was first recognised as a planetary nebula in 1918 by the astronomer Heber Doust Curtis.

The Dumbbell Nebula (also known as Messier 27, M 27, or NGC 6853) is a planetary nebula (PN) in the constellation Vulpecula, at a distance of about 1,360 light years.


Mirfak
The brightest star of this constellation is also called Algenib. Mirfak (Arabic for elbow) is a supergiant star of spectral type F5 Ib with an apparent brightness of 1.79m lying at a distance of about 590 light-years. Its luminosity is 5,000 times of our sun and its diameter is 42 times that of our sun. Mirfak is one of the navigational stars used in celestial navigation because like Mirfak they are so bright and visible in the night sky.

The Astrolabe

An astrolabe (Greek: ἁστρολάβον astrolabon, “star-taker”) is a historical astronomical instrument used by astronomers, navigators, and astrologers. Its many uses include locating and predicting the positions of the Sun, Moon, planets, and stars; determining local time (given local latitude) and vice-versa; surveying; triangulation; and to cast horoscopes.

They were used in Classical Antiquity and through the Islamic Golden Age and the European Middle Ages and Renaissance for all these purposes.

A Treatise on the astrolabe by Nasir al-Din al-Tusi, Isfahan 1505.
In the Islamic world, astrolabes were also used to calculate the Qibla and to find the times for Salah prayers. So, for the practical everyday activity of prayer, the people of Islam needed to know the time of prayer, but also, as we shall see, but also the direction of prayer. If you were on the move as a muslim, you needed to be a navigator in time and space.

Qiblah (Arabic: قبلة‎, also transliterated as Kiblah) is an Arabic word for the direction that should be faced when a Muslim prays during Salah. Most mosques contain a niche in a wall that indicates the Qiblah.

Originally, the Qiblah (direction for prayer) for Muslims was toward the Noble Sanctuary (Temple Mount) in Jerusalem. Today the Qiblah, for any point of reference on the Earth, is the direction of the Kaaba in Mecca. The change happened very suddenly during one noon prayer in Medina, in a mosque now known as Masjid al-Qiblatain (Mosque of the Two Qiblahs). Muhammad was leading the prayer when he received revelations from Allah instructing him to take the Kaaba as the Qiblah (literally, “turn your face towards the Masjid al Haram”).

Muslims do not worship the Kaaba or its contents; the Kaaba is simply a focal point for prayer.