Sunday, 31 May 2020

Astrognome A-Z of Constellations # 35 Equuleus

Equuleus the Little Horse
Equuleus constellation lies in the northern sky. Its name means “little horse” or “foal” in Latin.
In Greek mythology Equuleus is associated with the foal Celeris (meaning "swiftness" or "speed"), who was the offspring or brother of the winged horse Pegasus.
It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is the second smallest of the modern constellations (after Crux), spanning only 72 square degrees. It is also very faint, having no bright stars.
Alpha called Kitalpha which means ‘A Piece of the Horse’ has a magnitude of 3.9 Kitalpha lies at a distance of 190 light years it is a G7 class giant star.

Saturday, 30 May 2020

Astrognome A-Z of Constellations # 34 Draco

Draco the Dragon Circumpolar Northern Hemisphere
Dragons feature in many ancient legends, the body of Draco lies coiled around the celestial pole, although a large constellation it is quite faint being formed of a long line of curved stars ending in 4 stars that form a quadrilateral shape that represents the head of the dragon.
Alpha or Thuban which means ‘Snake’ was the North Star when the great pyramids were built in Egypt around 4,000 years ago. The position of the North Star changes in time due to the wobbling of the Earth. It takes the Earth around 24,000 years to wobble once meaning that during this period of time the North Pole of the Earth will describe a circle in the sky. In about 8,000 years time the bright star Vega in Lyra will be the North Star. Today we have Polaris in Ursa Minor as the North Star. People in the southern hemisphere are not so fortunate at the moment as there is no bright star to mark south. Thuban is 303 light years away and shines at magnitude 3.6 and is an A0 giant class star. It is hotter than the Sun.
Beta or Alward which means ‘The Old Mother Camels’ and has a magnitude 2.8 brighter than Thuban. It lies at a distance of 380 light years and is a G2 giant star and is slightly cooler than the Sun.
The brightest star in Draco is gamma or Eltanin which means ‘The Great Serpent’ it has a magnitude of 2.2 and is an orange K5 giant star, lying at a distance of 154 light years away.

Friday, 29 May 2020

Astrognome A-Z of Constellations # 33 Dorado

Dorado the Goldfish or Swordfish
The name Dorado is Spanish for mahi-mahi, or the dolphin-fish. The mahi-mahi has an opalescent skin that turns blue and gold as the fish dies. This may very well be the reason Dorado is sometimes called the goldfish.
Dorado is in the southern sky and was unknown to the Greeks it was the constellation of Dorado was one of twelve created by Petrus Plancius from the observations of Dutch navigators Pieter Dirkszoon Keyser and Frederick de Houtman and first appeared on a celestial globe published circa 1597-8.
Dorado was taken a bit more seriously when it was included by Johann Bayer in 1603 in his star atlas, Uranometria, there are no myths associated with this constellation
The only bright star is alpha at magnitude 3.3 it is an A0 class star, 169 light years away,
It is in Dorado that we can see the Large Magellanic Cloud (LMC), which is a satellite galaxy of our Milky Way Galaxy. The LMC is around 163,000 light years away.
The first recorded mention of the Large Magellanic Cloud was by the Persian astronomer `Abd al-Rahman al-Sufi Shirazi, (later known in Europe as "Azophi"), in his Book of Fixed Stars around 964 AD.
The next recorded observation was in 1503–4 by Amerigo Vespucci
Ferdinand Magellan sighted the LMC on his voyage in 1519, and his writings brought the LMC into common Western knowledge. The galaxy now bears his name.
The LMC is the fourth-largest galaxy in the Local Group, after the Andromeda Galaxy (M31), the Milky Way, and the Triangulum Galaxy (M33). There is a Small Magellanic Cloud in the constellation of Tucana the Toucan.
In 1987, the Supernova 1987A (SN 1987A) was observed in the LMC approximately 168,000 light years from Earth.
The supernova was discovered by Ian Shelton and Oscar Duhalde at the Las Campanas Observatory in Chile on February 24, 1987, and within the same 24 hours independently by Albert Jones in New Zealand. The supernova reached a peak magnitude of about 3.0 in May before its brightness declined in the following months.
Four days after the event was recorded, the progenitor star was identified as Sanduleak −69° 202, a blue supergiant

Transit of Venus 1874 Medal

Transit of Venus 1874 Medal .

I recently came across this. In 1874 the French Academy of Sciences presented a medal to those Frenchmen who were engaged in observing the transit of Venus in 1874.

Does anyone know if there was an equivalent medal struck for British astronomers?

On the medal which relates to mythology it describes ‘Venus in the simple costume of the goddesses, passes before the car of Apollo, the god of the Sun, while science observes the phenomenon on the Earth and records the results’.

The legend is the composition of a member of the Academy of Inscriptions.

On the reverse of the medal is the following inscription

8-9 DECEMBER 1874

Medal designed by M. Alphee Dubois

Thursday, 28 May 2020

Astrognome A-Z of Constellations # 32 Delphinus

Delphinus the Dolphin
A small constellation that dates back to the time of ancient Greece. The dolphin rescued the musician Arion from drowning after he was robbed and thrown off a ship, as a reward the dolphin was placed in the sky for ever.
In legend dolphins were the messengers of the sea god Neptune.
Delphinus is close to Altair, in summer triangle. Its brightest stars are only just above mag 4 but it is a small compact little group like a very loose star cluster. In shape the dolphin bears a vague resemblance to a tiny dim distorted Plough.
Its 4 main stars form a rectangle called Job’s Coffin the origin of this name is not known.
Alpha with a magnitude of 3.9 is 254 light years away and is a B9 class star.
Beta is a F5 giant class star and at magnitude 3.8 is slightly brighter than alpha it is 101 light years distant.
Gamma with a magnitude of 3.9 is 101 light years away and is a F7 class star.
Delta with a magnitude of 4.3 is the faintest of the main stars lying at a distance of 223 light years and is a K7 class star.
Delphinus lies in the milky way so a very rich area for star sweeps.
George Alcock discovered a nova on 8 July 1967 It continued to brighten, reaching a peak of magnitude 3.5 on 13 December 1967 before fading quickly to magnitude 5.1, and then varying between magnitudes 4.4 and 5.7, and reaching magnitude 4.2 in May 1968 before fading steadily; it was magnitude 9.75 by the end of 1971. In 1968 it was called HR Delphini.

Wednesday, 27 May 2020

Astrognome A-Z of Constellations # 31 Cygnus

Cygnus the Swan - Northern Hemisphere
The celestial swan is sometimes called the northern cross since its + shape is very striking. Its brightest star Deneb at magnitude 1.3 and is one of the members of the summer triangle. Although the faintest of the triangle it is actually is the brightest only appearing fainter because it is the most distant.
In mythology Cygnus represents a swan flying down the milky way, swans feature in many legends including that of Zeus who visited Leda wife of King Tyndareus of Sparta in the guise of a swan. The result of their union was Pollux one of the heavenly twins.
Alpha or Deneb which means ‘Tail of the Hen’ marks the top star of the northern cross has a magnitude of 1.3 and is a class A2 supergiant star with a surface temperature of around 8,000’C much hotter than our Sun, It lies at a distance of 2,600 light years.
Beta or Albireo or the ‘Hen’ is at the bottom star of the cross of Cygnus it has a brightness of magnitude 3.2, it is an orange K2 giant star and is 430 light years away. If you have a small telescope or a pair of binoculars you will see that Albireo is actually a double star with the companion star being a much hotter B class giant star of magnitude 5.1.
Gamma or Sadr which means ‘Breast’ is the middle star of the cross. It is brighter than beta with a magnitude of 2.2 at a distance of around 1,800 light years. It is a F8 supergiant star slightly cooler than the Sun.
To the left of gamma is epsilon or Gienah which means ‘Wing’. It is 73 light years away and shines at a magnitude 2.5. It is an orange K0 giant star indicating it is cooler than the Sun.
If you look to the right of gamma you will see delta which has no name. It is of magnitude 2.9 and is 165 light years away. It is an A0 class star.
Between gamma and beta is the variable star chi which can vary in brightness from magnitude 3.3 when it is easy to see down to magnitude 14.2 when a large telescope will be need to see it. Chi is a Mira type variable star named after omicron ceti or Mira the prototype star of this class of variable stars. It is a M6 giant class star, much cooler than the Sun.
Messier or M39 is an open cluster that can be seen as a fuzzy light patch of light north of Deneb shining at a magnitude or 4.6. It was first recorded by Aristotle in 325 BCE. M39 lies about 950 light years away and only contains about 30 stars.
NGC 7000 or the North American Nebula was discovered by William Herschel in 1786. This nebula is lying close to Deneb. Some people claim it may be visible to the naked eye under good, dark conditions, and a preferred object for amateur astrophotographers. Its mag is 4.4 but spread over a wide area.
It is called the North American nebula because it has the same shape as North America and is a great favourite with astronomers to photograph. It was first photographed by Max Wolf on December 12, 1890.
The distance to the North America Nebula is estimated at 1,600 light years.

Tuesday, 26 May 2020

Astrognome A-Z of Constellations # 30 Crux

Crux The Southern Cross – Southern Hemisphere
The smallest constellation in the sky, but one of the most celebrated and distinctive. It was formed from some of the stars of the constellation Centaurus by various seamen and astronomers in the 16th century. Crux means cross in Latin.
Johan Bayer incorporated these stars into his Uranometria star atlas in 1603 thus making it an officially recognised constellation.
Crux lies in a dense and brilliant part of the Milky Way which makes the famous Coalsack Nebula seem even more striking in silhouette against the star background.
Alpha or Acrux which is a 19th century name and has no ancient meaning. It has a magnitude of 0.8, it is B0 class star with a surface temperature of 22,500’C compared to the 5,800’C for the Sun. It lies at a distance of 320 light years.
Beta is a star of magnitude 1.2 lying 280 light years away its a B0 giant star also with a temperature of 25,000’ C
Gamma is 87 light years away and has a magnitude of 1.6 its a red M3 giant class star with a temperature of 3,300,C. It is the nearest red giant to the Sun.
Delta at magnitude 2.8 is the faintest of the four stars that make the Southern Cross. It lies 345 light years away, it is a B2 class star with a temperature of 22,000’C
The Kappa Crucis Cluster or NGC 4755 , also known as the Jewel Box (or Herschel’s Jewel Box), is an open star cluster in Crux. It is one of the youngest clusters ever discovered, with an estimated age of only 14 million years. Kappa is one of the brightest members of the cluster.
The 19th century English astronomer Sir John Herschel described the cluster as “a casket of variously coloured precious stones,” which is how the cluster appears in a telescope and how it subsequently got the name the Jewel Box.
The naked eye, the cluster appears like a star near beta, The brightest stars in the Jewel Box Cluster are supergiants. The three brightest stars got the nickname “traffic lights” because of their different colours.
The cluster has a visual magnitude of 4.2 and contains about a 100 stars. It is approximately 6,440 light years distant from the solar system.
The cluster can only be observed from the southern hemisphere. It was discovered by the French astronomer Nicolas Louis de Lacaille on his trip to South Africa in 1751-52.
The Coalsack Nebula is located about 600 light-years away.This huge, dusky object 35 light years across forms a conspicuous silhouette against the bright, starry band of the Milky Way and for this reason the nebula has been known to people in the Southern Hemisphere for as long as our species has existed.
It was first reported in Europe in 1499. The Coalsack like other dark nebulae, it is actually an interstellar cloud of dust so thick that it prevents most of the background starlight from reaching observers.

Lunar Occultation of Jupiter May 24th 1860

May 24th 1860 Lunar occultation of Jupiter

I have come across a report from Saturday May 24th 1860 of an occultation of Jupiter by the Moon observed from Manchester.

The occultation began at 4.34 pm and I quote “ Jupiter should have appeared at 6.13 pm but had not, this could be due to superfluous light above and below. By 7.00 pm I could distinguish Jupiter easily. I observed Jupiter until 8.00 pm when it became cloudy”.

A F Goddard,
Bury New Road, Manchester

Monday, 25 May 2020

Astrognome A-Z of Constellations # 29 Crater

Crater the Cup - Spring Sky
The second of the small constellations adjoining Hydra the other being Corvus. Crater although very faint it is one of the original 48 groups even though it contains no stars brighter than magnitude 3.5.
Crater represents the cup of Apollo and is associated with the neighbouring constellation of Corvus.
There are only stars that can be easily seen these are delta, alpha and gamma.
Delta is a magnitude 3.6 K0 orange giant star, lying 163 light years away.
Alpha at magnitude 4.1 is 141 light years away and is an orange K1 class giant.
Gamma is a magnitude 4.1 star A9 class star, at a distance of 86 light years.

Sunday, 24 May 2020

G F Chambers

May 24th 1915 death of G.F. Chambers

George Frederick Chambers died on May 24th 1915, he was born in 1841. Chambers was a barrister and astronomer. He became very well known due to the number of books on astronomy that he wrote. His first book was ‘A Handbook of Descriptive and practical Astronomy’.

His most popular books were a series of introductions to astronomy. The Story of the Solar System, The Story the Star, The Story of Eclipses, and The Story of Comets. He also produced a revised version of ‘A Cycle of Celestial Objects’ that was originally written by Admiral W H Smyth.

In 1865 he purchased a 4 inch telescope from Thomas Cooke of York

Astrognome A-Z of Constellations # 28 Corvus

Corvus the Crow -Spring Sky
A small but quite prominent constellation which is at its highest in the late spring evenings, the crow is low in the sky depicted sitting on the back of the water snake.
According to legend Apollo sent the crow to bring the water of life, but was unable to resist the unripe fruit of the fig tree, he let the cup of water (the constellation of Crater) fall to the ground. Realising that he was taking too long he hurried back to Apollo who discovered the truth and banished the crow to the sky. Another version has this same story but with Noah and the ark.
Four principal stars, Delta, Gamma, Epsilon, and Beta Corvi, form a quadrilateral shape, none are particularly bright but because they are in a barren part of the sky making the shape easy to see.
The brightest star in Corvus is gamma or Gienah which means ‘Wing’ is a star of magnitude 2.6, Gienah is a B8 giant star much hotter than the Sun, it lies at a distance 154 light years.
Beta is a magnitude 2.7 and is located 146 light years away, its a G5 giant star cooler than the Sun.
Delta or Algorab, which means the ‘Crow’ is a magnitude 3.0 star lying 87 light-years from Earth. Algorab is an A class star.
Epsilon has the traditional name Minkar, which means ‘The Nostril of the Crow’ and is a magnitude 3.0 star lying at a distance of 318 light-years from Earth. It is an orange K2 giant star.
Alpha or Alchiba, which is just below epsilon the meaning is unknown is a F1 class star, it has a magnitude of 4.0, and is 49 light-years from Earth.
As we have noted the star labelled alpha is not always the brightest star in a constellation. In Corvus alpha is actually the fourth brightest.

Saturday, 23 May 2020

Astrognome A-Z of Constellations #27 Corona Borealis

Corona Borealis The Northern Crown
Corona Borealis the Northern Crown which was given as a wedding present by Bacchus to Ariadne and was then cast by him into the sky when she died. It consists of an arc of seven fairly faint stars with the exception of alpha.
Alpha or alphecca which means ‘the bright (star) of the broken (ring of stars)’ is an AO class star at magnitude 2.2. it lies 75light years away.
Beta of Nusakan which means ‘The two lines (of Stars)’ is 112 light years distant. It is an A9 class star with a magnitude of 3.7
Gamma has a magnitude of 3.8 and is a B9 class star, it is 146 light years away.
There are two special variable stars in this small constellation.
R Coronae Borealis is a yellow supergiant which usually is just at the limit of naked eye visibility at magnitude 6.0 but at unpredictable times it will fade to as faint as magnitude 14. It is thought that this is caused by carbon rich particles building up in the atmosphere blocking the light from the star reaching Earth. These particles then disappear and the star then brightens once again.
There are only about 100 of these stars known. R itself was discovered by Edward Piggot in 1795.
T Coronae Borealis is also know as the Blaze Star, its a nova which erupted in 1866 reaching magnitude 2.2 and going novae again in 1946 reaching magnitude 3.0. It is called the Blaze Star because until around 20 years ago it was one of the few stars that had been observed to go novae more than once. Astronomers know today that all nova erupt more than once on times scales of decades or centuries.

Friday, 22 May 2020

Astrognome A-Z of Constellations # 26 Corona Australis

Corona Australis The Southern Crown
Corona Australis the Southern Crown is a counterpart in the southern hemisphere for the Northern Crown or Corona Borealis in the northern hemisphere. It is formed of a curve of faint stars which is easily recognisable, however it cannot be seen from Britain.
It has been known since the time of the astronomers of ancient Greece and in mythology was said to have been worn by the centaur Sagittarius which it lies next to in the sky.
There are only two stars worth mentioning,
Alpha at magnitude 4.1 and lying 125 light years away and is an A class star
Beta which lies just beneath alpha is also of magnitude 4.1, it is an orange K3 class giant star 470 light years away.

May 22nd 905 Great Comet

May 22nd 905 The Great Comet

On May 22nd 905 a comet appeared in the constellation of Gemini, by June 12th its brightness was very intense and its tail stretched across the sky. It was visible for 3 weeks.

During medieval times comets were often considered ill omens and bringers of bad fortune, in 899 King Alfred the Great had died and his son Edward and his nephew Ethelward were contenders for the throne.

However the Vikings from Denmark were also attacking the country. Ethelward joined forces with the Vikings. In the summer of 905 when the comet was high in the sky a battle was fought between a group of men who supported Edward and a force led by Ethelward and the Vikings. Although the Vikings were successful Ethelward was killed ensuring that Edward would continue to rule the country until 924.

I am sure that an astrologer of the time would have predicted the death of such a noble person.

Thursday, 21 May 2020

Astrognome A-Z of Constellations # 25 Coma Berenices

Coma Berenices - Berenice’s Hair
Yet another faint constellation with no really bright stars, although it has an ancient legend it was only formed by Tycho Brahe in 1601. According to legend Queen Berenice of Egypt vowed to cut off her beautiful hair and place it in the temple of Venus, provided that her husband returned safely from a war against the Assyrians. When the king returned Bernices kept her promise and so impressed the gods that they transferred the flowing locks of her hair to the night sky.
Alpha or Diadem which means the ‘Braid’ is of magnitude 4.3 which is 58 light years away, it is a F5 class star somewhat hotter than the Sun.
A line drawn upwards from alpha points to beta also at magnitude 4.3 and is 30 light years distant, its a G0 class star slightly hotter than our Sun.
To the right of beta is gamma slightly fainter at magnitude 4.4, it lies 170 light years distant and is an orange K3 class giant star cooler than the Sun.
The rest of the constellations seems blank but if the sky is really clear there appears a shimmering effect in this part of the sky, this is the faint glow from the 30 or so galaxies that make up the so called Coma Cluster of Galaxies, which can of course be seen better with binoculars and larger telescopes.
All of the main stars and galaxies in Coma Berenices cannot be seen if there is any mist or haze around.
I cannot resist mentioning one galaxy that you would need a telescope to find this is M64, the Black Eye Galaxy which was discovered by Edward Pigott in 1779 while living at in Frampton House, Llanywit Major in Wales. Edward Pigott would go onto York to work with the deaf astronomer John Goodricke and I christened them ‘Fathers of Variable Star Astronomy’ because of their work on variable stars.

Wednesday, 20 May 2020

Astrognome A-Z of Constellations # 24 Columba

Columba the Dove
Columba the Dove which represents the dove that followed Noah’s Ark, or some legends say it was the dove that the Argonauts sent ahead to help them pass safely through the clashing rocks at the entrance to the Black Sea. If it was higher in the sky it would be quite easy to see. Columba was added to the night sky by the Dutch astronomer Petrus Plancius in 1592.
Alpha or Phact which means ‘Ring Dove’ is of magnitude 2.6 and is 260 light years away. It is a B7 class star with a surface temperature of 12,500 ‘C much hotter than the Sun.
Just below alpha and to the left is beta or Wazn which means ‘Weight’. It is a K1 orange-hued giant star of magnitude 3.1, Wazn is 87 light-years from Earth.

Tuesday, 19 May 2020

Astrognome A-Z of Constellations # 23 Circinus

Circinus the Pair of Compasses – Southern Sky
Another small and obscure constellations added to the southern sky by the French astronomer Nicolas de Lacaille in the 18th century. There does appear to be a lack of imagination ith the constellation, there are no stars to represent the compasses. It is the 4th smallest constellation in the sky.
The brightest star is alpha at magnitude 3.2 lying 54 light years away, it is an A7 class star.
The only other star worth mentioning is beta at magnitude 4.1 and is 93 light years away. It is an A3 class star.
Circinus could easily have been absorbed into the neighbouring constellations of either Centaurus, or Trianglulum Australe.

Alcuin 735 - 19th May 804

Alcuin 735-19th May 804

One of the greatest Saxon scholars, Alcuin was born in Northumbria possibly in York itself in 735 , he would go on to become one of the best sources of information during the latter part of the eighth century. The young Alcuin went to the cathedral church school of York during the golden age of Archbishop Ecgbert who had been a disciple of the Venerable Bede. Here Alcuin became a monk and teacher. Within the monastic world he was able to gain access to magnificent libraries, he wrote educational manuals and copied classical texts including those of the great scientists of Greece, it was here that Alcuin became interested in astronomy.


In 781 when he was returning from a visit to Rome he met with the King of the Franks, better known as Charlemagne who would unite most of Western Europe for the first time since the fall of the Roman Empire in the west, and apart from building a massive empire Charlemagne was also very interested in astronomy.

At Charlemagne’s invitation, Alcuin joined the royal court in 781, and became one of the king’s chief advisers on religious and educational matters. Alcuin was made head of the palace school at Aachen, and he established a great library there.

Charlemagne was fascinated by the movements of the stars and studied them carefully with the help of Alcuin and it was probably this work that produced some wonderful images of the constellations, the Leiden Aratea, this were copies of images of the constellations that had been produced by the Greek poet Aratus 310 BCE- 240 BCE whose work described the constellations and other celestial phenomena.

Leiden Aratea Charts

Alcuin would have been aware of this work and possible encouraged Charlemagne to get them re produced, but he did not live to see the work completed dying on 19th May 804 CE. The constellations themselves were produced probably near Aachen around 816 CE and even Charlemagne never saw this work being completed as he died in 814 CE. If it had not been for Alcuin setting up the great library at Aachen the wonderful Leiden Aratea constellations images would probably never have been reproduced.

Monday, 18 May 2020

Astrognome A-Z of Constellations # 22 Chameleon

Chameleon Circumpolar Southern Hemisphere
A very dull and bland constellation, Chamaeleon is a small constellation which can be found close to the South Pole and therefore invisible from Britain. Unlike many other animals named for the southern skies such as the Thrush, Cat and Reindeer it has remained in use. It was named after the Chamaeleon which can change its colour. It was added to the night sky in 1598 by the Dutch astronomer Petrius Plancius.
The constellation like the lizard it is named after can be difficult to locate as there are no bright stars. None of the stars have any names and there is no mythology attached as this group was not known to the Greeks.
Alpha is a magnitude 4.1, 64 light years away, it an F5 class star hotter then the Sun.
Beta is a B4 class star much hotter than the Sun and has a brightness of magnitude 4.2 star and is 300 light years away
Gamma is a K5 orange giant star cooler than the Sun and is 420 light years away.

Asteroid 758 Mancuria

Asteroid 758 Mancuria

On May 18th 1912 Harry Edwin Wood who was chief assistant at the Union Observatory in South Africa discovered an asteroid, it was named Mancuria after the city in which he was born, Manchester. He would discover 12 asteroids between 1911-1932.

Mancuria is the Latin name for Manchester

Sunday, 17 May 2020

Astrognome A-Z of Constellations # 21 Cetus

Cetus the Whale or Monster- Autumn Sky
Cetus is a Large constellations with few bright stars, a line drawn down from the two left hand stars of the square of Pegasus will lead to a magnitude 2.0 star this is beta ceti, although not a particularly bright star it is in a very barren area so is quite easy to see. To be honest the rest of Cetus is not easy to locate as it is low down in the south and any haze in the sky makes it difficult to see many of the stars of Cetus.
In mythology Cetus was the kraken, the monster sent by Neptune to eat the princess Andromeda, the monster today has turned into a more harmless Whale.
Alpha or Menkar which means ‘Nose’ is a magnitude 2.5, M1 giant class star, lying 250 light years away. As it is a red giant it is much cooler than the Sun.
The brightest star in Cetus is beta or Diphda which means ‘Tail’. It has a magnitude of 2.0 and is a K0 giant star. Although it is hotter than Menkar, Diphda is still not as hot as the Sun.
Tau Ceti is mentioned here only because it has appeared in many science fictions films and shows. It is a magnitude 3.5 star lying around 12 light years away. It is a G8 class star fairly similar to our Sun.
Since 2012 there has been evidence of at least 5 planets orbiting the star, even before this Tau has appeared in much science fiction. There have around 30 different novels and tv programmes including Star Trek the Next Generation, Star Trek Voyager and Star Trek Enterprise. The star also figured in Dr Who in 1975 and in the 1968 film Barbarella.
If Tau has some notoriety then it is omicron that takes the astronomical show.
Omicron or Mira which means ‘The Wonderful’. Mira has a long history. It was seen by the Dutch astronomer Fabricius in 1596 and recorded as being of the third magnitude, but a few weeks later it could not be seen. Johann Bayer the German astronomer who allocated the Greek letters to the stars in the constellations saw it in 1603 and allocated it the omicron, but after a few weeks it had disappeared again.
It was the first star to be recorded as a variable star and was accordingly given the title of the wonderful. It is unclear if the astronomers of ancient Greece were aware of the light changes in Mira.
The name was first used the Polish astronomer Johnanne Hevelius in the 1662. It was later established that Mira has a period of around 331 days and at its brightest it can become as bright as the North Star, but when at its faintest it drops to magnitude 10 and cannot be seen even with binoculars or a small telescope. The maximums are quite unpredictable and sometimes at maximum it will not even reach the 4th magnitude.
Mira is around 270 light years away and is a M7 giant star and has a surface temp of 2,700-2,900 ‘C much cooler than the Sun.
Mira is the prototype for the Mira type variable stars. This is a class of many 100s of red giant stars which vary in light range of 5-9 magnitudes over a period of about 60-700 days.

The Perth Meteorite

The Perth Meteorite May 17th 1830

A small meteorite fell on May 17th 1830 in a field known as North Inch at Perth, Scotland. A  part of the meteorite was recovered and was about 7 inches wide. The only record astronomers have comes from a Dr Thomson of Glasgow who says that during a thunderstorm on May 17th a meteorite fell at around 30 minutes after midday.

It was a stone meteorite and sadly since its fall in 1830 most of the meteorite has been lost and only around 2 grammes survive today.

Saturday, 16 May 2020

Astrognome A-Z of Constellations # 20 Cepheus

Cepheus The King
It has often been said that “The female of the species is more deadly than the male”. In the case of the constellations and with the story of the Cassiopeia legend, the female of the species is certainly the more conspicuous than the male, since King Cepheus cannot be compared with his wife Cassiopeia.
Cepheus is not particularity easy to identify since he is faint and has no obvious shape. A good way to find Cepheus is to draw a line from Dubhe and Merak the pointers in Ursa Major pass through the North Star and you will reach a faint 3rd magnitude star, Gamma before reaching the more easily found ‘W’ of Cassiopeia.
Cepheus takes the form of a large rather faint diamond which is in the area between the North Star, Cassiopeia and Deneb in Cygnus one of the stars in the summer triangle.
Alpha or Alderamin which means ‘Right Shoulder’ has a magnitude of 2.5 it is an A8 class star and is 49 light years away.
Beta or Alfirk which means ‘Herd’ varies very slightly between magnitude 3.2 to 3.3 it’s the prototype variable of the beta Cepheid variables, these are very hot and blue stars which vary very slightly over a period of a few hours. In the case of beta it varies every 4.5 hours. Beta is B1 class star with a surface temp of a massive 26,500`C, and is 700 light years away.
Gamma or Errai which means ‘Shepherd’ is 45 light years away. Errai is a K1 giant indicating it is cooler than the Sun, it has a magnitude of 3.2. In around the 4,000 CE gamma will become the North Star.
Delta, which has no name is the famous variable star discovered by John Goodricke in York in 1784. It is the prototype Cepheid type variable which astronomers use today to work out how far away galaxies are. There is something called the period luminosity law. A classical Cepheid's luminosity is directly related to its period of variation. The longer the pulsation period, the more luminous the star. This relationship was discovered by Miss Henrietta Leavitt at Harvard in 1912.
Delta varies between magnitude 3.6 and 4.3 every 5 days and 9 hours. If you can locate delta try to watch it change in brightness as it goes through its cycle. Delta is about 887 light years away, its varies from a F5 supergiant to a G1 supergiant class star, with a surface temp which changes from 5,500’C to 6,800’C during its cycle.
Mu Cepheus the Garnet Star so named by William Herschel because of its striking red tint colour. It’s a M2 class red supergiant with a surface temperature of 3,500’C, mu is 2,800 light years away. Mu is a variable star it varies in brightness erratically between magnitude 3.4 and 5.1. Many different periods have been reported, but they are between either 860 days or 4,400 days.

Friday, 15 May 2020

Astrognome A-Z of Constellations # 19 Centaurus

Centaurus The Centuar
A large rich and splendid constellation representing a Centaur who in Greek mythology represented the scholarly centaur Chiron who was then tutor to many of the Greek heroes. He was placed in the sky after accidentality being struck by a poisoned arrow shot by Hercules.
Sadly from Britain hardly any of Centaurus is above the horizon although it is true that from the south coast on a very clear night it might just be possible to see the stars iota and theta but they cannot be seen from the north of England.
Alpha or Rigil Kentaurus which means ‘Foot of the Centaur’ shines with a magnitude of 0.0 is the 4.37 light years from Earth. Alpha is actually composed of three stars A, B, and C. It is one of the finest binary stars in the sky which was discovered in 1689 by Father Richaud at Pondicherry in India. The A component is a G2 class star slightly hotter than the Sun with the B component being K1 class star cooler than the Sun they orbit each other every 80 years.
However it is C component or to give its name Proxima that is the closest star to us being a mere 4.24 light years or around 24,000,000,000,000 million miles away. It takes over 200,000 years to orbit the A and B stars, Scottish astronomer Robert T. A. Innes discovered Proxima in 1915. It is a small red dwarf with planets that orbit the star.
Beta or Agena which means ‘To Be Present’, is a B1 giant star much hotter than the Sun, with a magnitude of 0.6 and lying at a distance of 390 light years.
Gamma of magnitude 2.2 is 130 light years away and is an A1 class star hotter than the Sun.
Eta is 306 light years away and shines at magnitude 2.6 and is a hot B1 class star.
Omega Centauri NGC 5139 is the largest and brightest globular cluster in the sky, it is so bright that it was first catalogued in 150 AD by Ptolemy and it was Bayer in 1603 who gave it the Greek letter omega. It appears as a magnitude 3.7 star. It is 15,800 light years away and has a diameter of 150 light years and contains around 10 million stars.

May 15th 1910 Halleys Comet from Meeannee, N.Z.

Halleys Comet from Meeanee in 1910

Edward Crossley was a wealthy industrialist who owned the Crossley Carpet Mill in Halifax, Yorkshire. In April 1867 he purchased a 9.3 inch telescope from Thomas Cooke of York, the telescope would be used for over 30 years in Halifax, upon Crossley’s death in 1905 the telescope was brought by the Rev. David Kennedy in New Zealand, it was placed in an observatory at Meeanee, it was at the time the second largest telescope in New Zealand. This is the Crossley Telescope.

In 1910 Halley’s comet returned to the skies and on the 15th May 1910 the Crossley 9.3 inch telescope was used to take a photograph of the comet from the Meeanee observatory.

Baileys Beads or Tear Drops from York

Bailey’s Beads or Tear Drops of York May 15th 1836

An annular eclipse of the Sun was visible on May 15th 1836 from a large part of Scotland and the very north of England. One of the astronomers who went to watch the eclipse was Francis Bailey who went to Inch Bonney in Roxburghshire and his description of what he saw would lead to a term familiar to everyone who watches eclipses of the Sun, namely The Baileys Beads, this is when light is seen to pass through mountain ranges around the edge of the Moon. However things could have been different….In York at the York Observatory members of the Yorkshire Philosophical Society also saw the eclipse and described it as looking like tear drops. So what happened?

It was very simple really Francis Bailey who had helped to found the Royal Astronomical Society sent in a report describing what he saw, the people in York did not. What we call today Baileys Beads could have been the ‘Tear Drops from York’ Another case of he who hesitates is lost!!

Baileys Beads

An annular eclipse of the Sun occurs when the Moon passes in front of the Sun but is a little bit further from the Earth and cannot therefore cover the entire disc of the Sun, it blocks out much of the sunlight but leaves a yellow ring in the sky. The word annular comes from the Latin word ‘annulus’ meaning ring of fire.

Thursday, 14 May 2020

Astrognome A-Z of Constellations # 18 Cassiopeia

One of the most prominent constellations in the northern sky, the main stars forms a distinctive letter W or M in the sky, this depends on which way we view the constellation. It is circumpolar from Britain which means we can see it all year round. In mythology it represents a queen from a land a long time ago who upset Neptune god of the sea.
Cassiopeia can be found by using the pointers from Ursa Major passing a line past the North Star and then continuing to Cassiopeia,. and in any case it is very easy to find.
Cassiopeia and Ursa Major are on different sides of the North Star so when ever Ursa Major is high in the sky Cassiopeia is low down and vice versa.
Alpha Cassiopeiae or Schedar which means ‘Breast’ is a magnitude 2.2 star, it is a KO giant star with a surface temperature of 4250`C compared to 5,800`C for our Sun. Schedar is 230 light years away. During the 19th century it was thought to vary in slightly in brightness but this has not been confirmed in recent times.
Beta Cassiopeiae or Caph which means ‘Palm’ is a magnitude 2.3 star, it is a class F2 giant 55 light years away. Its surface temperature is hotter than the Sun’s.
Gamma Cassiopeiae which has no Arabic name. It’s a BO class star with a surface temperature of an incredible 24,700`C, and lies 550 light years away. It is a variable sta,r its brightness varies between magnitude 1.6 and 3.0. It is the prototype of the Gamma Cassiopeiae type eruptive variable stars. This group is so rare that there are only about 10 examples which are known to exist.
Before 1910 gamma appeared constant at magnitude 2.2 then it made puzzling and unpredictable light variations. In April 1937 it slowly brightened to magnitude 1.6 then decreasing back to magnitude 3.5 in 1940. When at its brightest it is brighter than both alpha and beta. It then slowly brightened again so that by 1954 it was back to magnitude 2.5. By 1976 it had brightened to magnitude 2.2 where it has hovered around ever since, however it is such an unpredictable star that no one knows what it might do next.
Delta Cassiopeiae or Ruchbar which means ‘Knee’ is an A5 class star hotter than the Sun, it is of magnitude 2.7 and is 100 light years away.
Epsilon Cassiopeiae or Segin the meaning of which is unknown, lies 410 light years away. It has a brightness of magnitude 3.4 and is a class B3 star much hotter than the Sun.
Slightly to the right of beta or Caph lies rho a peculiar irregular variable star lying around 3,400 light years away. The light from rho varies between 4.1-6.2, its a yellow hypergiant which varies between a F class and K class star. The star is so big that if it was placed where our Sun is everything out to the planet Mars would be inside it. Its temperature varies between about 5,000` to 7,000` C There are only about 12 known of these hyper giants known in our galaxy. It is believed that this star is on its way to becoming a supernova.
SN 1572
Sometimes called Tycho’s Star this was a Super Nova, this is a star that destroys itself in a massive explosion. It was not discovered by Tycho but he gave the most accurate series of observations on the star, which is why the star bears his name. This supernova would become the most brilliant object in the sky during the last 500 years. It reached around mag -4.
He first saw the star on November 11th 1572. For several weeks it outshone every star in the night sky. It could even be seen in daylight, when the Sun was low in the sky. The star was visible to the naked eye (there were no telescopes at this point) for about 16 months fading from view in March 1574.
At this time of course people believed that the heavens never changed so to see a new star suddenly appear certainly caused a massive amount of interest.
The supernova was between 8,000-9,000 light years away.

Wednesday, 13 May 2020

Astrognome A-Z of Constellations # 17 Carina

Carina The Keel -Southern Hemisphere
One of the most intriguing of the ancient legends tells how a band of heroes headed by Jason sailed off in search of the Golden Fleece. This fleece had come from a magical ram which was able to fly and which has rescued two royal children from a cruel stepmother, carrying them to the land of king Aetes. After the ram died the fleece was placed in a tree in a scared grove guarded by a particularly nasty dragon. Much to the annoyance of King Aetes Jason managed to kill the dragon and took the fleece back to his own country.
Among the heroes concerned in this expedition were Hercules and the heavenly twins Castor and Pollux. The ship they travelled in was called the Argo and fittingly enough Argo Navis used to be the largest in the sky. I say used to, because it was such an unwieldy constellation that in 1750 the French astronomer Nicolas Louis de Lacaille broke it up into 3 parts, Carina the keel, Puppis the stern and Vela the sails.
Carina is invisible from Britain which is a pity as it contains Canopus the 2nd brightest star in the sky.
Alpha or Canopus which is named after the pilot of the fleet of the Greek Sparta king Menelaos and appropriately enough today Canopus is now used in navigation by spacecraft. At magnitude -0.7 it is the 2nd brightest star in the sky, Canopus is an A9 class giant star with a surface temperature of 6,600 ‘ C compared to the Sun’s 5,800’C.
Beta or Miaplacidus which means ‘Placid Waters’ is a star of magnitude 1.7 it’s an A3 class giant star with a surface temperature of 8,600`C and is 113 light years away.
Epsilon is one of 57 navigation stars that are used by the RAF. It is 610 light years away, epsilon is a K3 giant star and is cooler than our Sun. The star has a magnitude of 1.9 slightly brighter than the North Star.
Theta has a magnitude of 2.8, its a B0 class star indicating it is hotter than the Sun. Theta lies at a distance of 460 light years. it is the brightest star in the open star cluster IC 2602, a cluster with the letters IC stands for Index Catalogue and was published in 1896 as an addition to the NGC or New General Catalogue which was produced in 1888. IC 2602 is known as the southern Pleiades, there are about 75 stars there.
Iota or Aspidiske which means ‘Shield’ has a magnitude of 2.2 and is an A9 class supergiant star much hotter than the Sun, it is 690 Light years away. Due to the wobbling or precession of the Earth Aspidiske will become the South Pole star in 8100 CE.
Eta a very remarkable star, it was recorded by Edmund Halley in 1677 as a star or around magnitude 4.0. During the next 100 years it slowly brightened to about magnitude 2.0 but then it faded again to magnitude 4.0. In 1820 it rose once again to magnitude 2.0, then in April 1843 it suddenly brightened to magnitude -0.8 it outshone every star apart from Sirius. By 1866 it had dropped below naked eye visibility, it is now around magnitude 4.5. So what’s going on?
According to theory eta should have destroyed itself with the massive eruption of 1843 but it didn’t, the theory at the moment is that eta is in the throes of destroying itself in another massive explosion. The majority of astronomers think that eta has one final stage to go through, becoming what is known as a Wolf-Rayet star.
Wolf-Rayet stars represent a final burst of activity before a huge star begins to die. It could be tomorrow or within the next 100,000 years which on the cosmic scale is a blink of the eye. These stars, which are at least 20 times more massive than the Sun, “live fast and die hard”. Their names come from two French astronomers, Charles Wolf and Georges Rayet, who discovered the first known star of this kind in 1867. When eta does explode it will be spectacular!
Eta lies within NGC 3372 or the Carina Nebula, which is sometimes confusingly called the Eta Carina Nebula, its an open cluster containing many other massive O class stars.
NGC 3532 is another bright open cluster appearing as a magnitude 3.0 cluster, it lies at a distance of about 1,300 light years it contains about 150 stars.

Tuesday, 12 May 2020

Astronomy in the North West # 11 Joseph Baxendell and the Blaze Star

Joseph Baxendell and the Blaze Star

On May 12th 1866 Baxendell together with several other astronomers discovered a bright star appear in the constellation of Corona Borealis. This was a nova and it reached a magnitude of 2.0 which is as bright as bright as the North Star.

The word Nova comes from the Latin meaning New when in the middle ages astronomers thought these were new stars being created.

A nova is not a new star but a double star system one small hot star and one larger but less massive star, the hot small star pulls gas from the less massive star this will fall onto the hot surface and be thrown into space. The star then brightens and appears in the sky, this is a nova.

Nova System

There is every possibility that he may have seen it a few days earlier on May 7th when he was checking all known variable stars to naked eye visibility.

The nova later designated T Corona Borealis would become known as the Blaze Star because in 1946 it went novae again and it reached magnitude 3.0. This was the first nova known to do this . It became the first of what astronomers now call re current novae, although Baxendell could not know of this.

Astronomers now know that all nova are recurrent and that they can brighten up over a period of decades or centuries.

Astrognome A-Z of Constellations # 16 Capricornus

Capricornus the Sea Goat - Autumn Sky
Low down on early autumn evenings is one of the constellations of the zodiac, Capricornus is depicted as a goat with the tail of a fish. Although a very faint group it has one of the oldest mythological associations. Capricornus is also sometimes identified as Pan, the god with a goat's head, who saved himself from the monster Typhon by giving himself a fish's tail and diving into a river.
The brightest star is Delta Capricorn or Deneb Algedi which means the ‘Goats Tail’ with a magnitude of 2.8, its 39 light years from Earth. It is an A7 giant star hotter than our Sun.
The next brightest star is beta or Dabih which means `Lucky One of the Slaughterers` it is magnitude 3.1 star and is 328 light years away. It is K0 giant indicating it is cooler than the Sun.
The third brightest star is alpha which should of course be the brightest but as we have already discovered many times as we look at the constellations it doe not always work out that way. Alpha or Al Giedi which means the ‘Forehead’ is actually the third brightest, it is also a double star, meaning that if you look very carefully you will see two stars. In this case the two stars are not connected in a binary system they are what astronomers call an optical double.
Alpha 1 is a magnitude 4.2 star at a distance of 870 light years and is a G3 supergiant slightly cooler than our Sun while alpha 2 is a magnitude 3.6 star at a distance of only 102 light yeas it is a G8 giant star.
Just to the right of delta is gamma or Nashira which means the ‘Fortunate One’, it lies at a distance of 139 light years away and has a magnitude of 3.7 and is a K0 class star being cooler than the Sun.

Monday, 11 May 2020

Astrognome A-Z of Constellations # 15 Canis Minor

Canis Minor the Lesser Dog – winter sky
In mythology it is the smaller of the dogs that follows Orion the Hunter.
It has only one bright star alpha or Procyon which means ‘Before the Dog’, this is because it rises before Sirius. Procyon is the 8th brightest star in the sky with a magnitude of 0.3. It is close to the Earth being only 11.5 light years away. It is an F5 class star meaning its slightly hotter than our Sun.
Procyon forms a very prominent and large triangle with Sirius in Canis Major and Betelgeuse in Orion.
By a remarkable coincidence both of the dog stars are accompanied by white dwarfs. The pup orbiting Sirius was discovered by Alvan Clark in 1862 when he was testing a new telescope. The white dwarf orbiting Procyon was discovered in 1896 at the Lick observatory using the 36 inch refractor.
White dwarfs are the remains of a star that has used up all its hydrogen fuel and what remains is mostly helium, this makes them super dense objects with a tea spoon weighing many tons.
The only other notable star is beta or Gomeisa which means the ‘Bleary Eyed One’ It is of magnitude 2.9 and is 160 light years away, its a B8 class star which means it is hotter than the sun.
Just above beta is the faint star gamma which has a magnitude of 4.3 and is a K3 giant class star which is cooler than our Sun, gamma is 320 light years distant.

Sunday, 10 May 2020

Astronomy in the North West # 10 May 10th 1871 Markings on Venus

May 10th 1871

Venus- Mr Henry Ormesher of Manchester has frequently observed the planet during the last few months. He has on several occasions succeeded in detecting the dark markings. He says - ‘May 10th 8 h the markings were clear and well defined and remind me very much of the planet Mars, having much the same appearance’. On May 21st and May 29th he also saw dusky markings on the planet’s surface with his 5.25 inch refractor.

Astrognome A-Z of Constellations # 14 Canis Major

Canis Major The Greater Dog
Canis Major is a stunning constellation with many bright stars and clusters, unfortunately for observers in Britain it is always low in the sky so we never see it at its best. It represents one of the two dogs the other being Canis Minor that follows at the heels of Orion the Hunter.
The brightest star in Canis Major, Sirius is also the brightest star in the sky. This is the dog star and sometimes known as the scorching one or the Nile star. Although low down in winter skies it is easy to find. If you do need a guide to find Sirius you can use the stars of Orion’s belt and draw a line down and to the left this will lead you to Sirius.
At magnitude -1.4 (it has a minus sign in front of the magnitude number because it is so bright, there are 3 stars with minus magnitudes in the night sky) Sirius outshines all the other stars in the sky but appearances can be deceptive because Sirius is very close to us being only 8.6 light years away. It is an A class star which means it is hotter than the Sun with a temperature of 9,500’C compared to 5,800’C of the Sun.
Sirius was very important in ancient Egypt because astronomers/priests would wait to see Sirius rise just before the Sun rose in the morning sky. They knew this meant the river Nile was about to flood, it was at this point that farmers had to make sure their fields were ready for the inrush of water and sediment that would help their crops to grow. This astronomical event is known as the Helical Rising.
Sirius has a companion star a white dwarf which was discovered by the American telescope maker Alvan Clark in 1862 when he was testing a 15 inch refractor. A white dwarf is a small, faintly lit object made of super dense stuff called degenerate matter. It is thought that most stars, including the Sun, will end their days as white dwarfs. A teaspoon full of white dwarf material would weigh many tons.
As Sirius is the Dog Star it seems appropriate that the small companion star which is officially known as Sirius B should be known unofficially as ‘The Pup’
We know that the brightest stars in a constellation are allocated a letter from the Greek alphabet with the brightest being alpha then beta etc., and we have also seen that the system often does not work, well here we go again.
The second brightest star is epsilon (5th letter of the Greek alphabet) or Adhara which means ‘Virgins’ and has a magnitude of 1.5 it is a B2 giant star with a whopping surface temperture of 22,500’C which makes our Sun seem very cool by comparison. Adhara is 440 light years away.
A line drawn down from Sirius and slightly to the left leads to delta or Wezen which means ‘Weight’ which has a magnitude of 1.8 and is a F8 supergiant and is slightly hotter than the Sun, Wezen lies about 1600 light years away. It is thought that in the next 100,000 years Wezen could destroy itself in a supernova explosion.
To the right of Sirius is beta or Murzim which means ‘Announcer’ and should be the 2nd brightest star in this constellation however it is in fact the 4th. Murzim is a magnitude 2.0 blue giant class star lying 500 light years away, its another very hot star with a surface temperature of 22,750’C.
Below Wezen and to the left is eta or Aludra the meaning is unknown and is B5 supergiant of magnitude 2.4 , with a temp of 14,750`. Aludra is about 2,000 light years away. It will also become a Supernova in the next few million years.
A line drawn to the right from epsilon will lead to zeta or Phurud meaning the ‘Bright Single Ones’. This is a magnitude 3.0 star, 362 light years away. Another B class star this time a B2 with a temperature of 18,400’ C.
To the left of Sirius is gamma or Muliphein whose meaning is unknown. Gamma is of magnitude 4.1 and is a B8 giant with a surface temperature of 13,100’C and lies 440 light years away. There is a mystery here because Gamma appears to have varied over a period of many 100s of years. It is recorded that in 1670 the Italian astronomer Montanari said that it disappeared from view. It was not observed for another 23 years.
Below Sirius is an open cluster, M41 which contains about 80 stars and shines at a magnitude of 4.5 it is about 2,100 light years away it was recorded as far as back as 325 BCE by Aristotle in Greece. In ‘modern time’ it was reported by the Italian astronomer Hodierna in 1654 and recorded by Messier in 1765.
NGC 2362
An open star cluster NGC 2362 was discovered by Hodierna in 1654 this cluster was not reported again until it was eventually found by William Herschel (discoverer of the planet Uranus in 1781) on March 4, 1783
NGC 2362 contains about 60 stars, and is of mag 4.1 and is only about 25 million years old. The brightest star in this cluster is tau which is of magnitude 4.39 and is a class O9 supergiant star with a surface temperature of an incredible 31,500’C, it is one of the most luminous supergiants known. The cluster is about 5,000 light years in distance from Earth.