Thursday, 30 April 2020

Astrognome A-Z of Constellations # 4 Aquarius

Aquarius – The Water Bearer - Autumn Sky
Aquarius is one of the most ancient of constellations. The Babylonians saw this area of sky as a man pouring water from a jar and it is still represented this way today. Aquarius is one of the zodiacal constellations and according to the Greeks it is linked to Ganymede, cup bearer to the Olympic gods.
It’s in the Zodiac a belt of stars made up of 12 constellations that stretch around the sky, actually there are 13 constellations in the Zodiac, no one ever talks about Ophiuchus. The zodiac is where the Sun, Moon and planets will always be found in the sky. Many people get confused with astronomy and astrology, astronomy is the science of the stars while astrology is the pseudo science that tries to link people’s characteristics with the positions of the planets against the starry background.
Aquarius is not a particularly bright constellation and can be found below the square of Pegasus. The most prominent part of the constellation is the Y shaped figure of 4 stars representing the water jar itself centred on the star zeta. Together with gamma, eta and pi this little area is often called the ‘Water Jar’.
The brightest star is beta whose name is Sadalsuud which means ‘luck of lucks’ is of mag 2.8 and is about 520 light years away. It is a G0 supergiant At 5,400`C it is slightly cooler than the sun.
The second brightest star is alpha at mag 2.9 is a G class supergiant class star, however this is a G2 type star, slightly cooler than the Sun it has a proper name which is sadalmelik which means ‘luck of the king’. Alpha is about 540 light years away. It has a surface temperature of around 4,900`C.
Delta or Skat which means ‘leg or shin’ is the third brightest star at magnitude 3.3 and about 113 light years away. It is an A3 star with a surface temperature of about 8, 700`C much hotter than the Sun.
The following stars make up the water jar
Gamma or Sadachbia, its name means ‘luck of the homes’ (tents).has an apparent visual magnitude of 3.8 and is 164 light years distant. It is an A0 class star with a surface temperature of about 10,200`C, our Sun is about 5,800’C
Zeta which is slightly above and to the left of gamma is an unnamed and  is a binary star, which means there are two stars here, however without a small telescope you would not be able to see the two stars. Zeta is located at the centre of the water jar asterism. The two stars are yellow white type stars one is a F3 star at magnitude 4.2 the other a F6 giant at magnitude 4.5 . Both are hotter than the Sun . The pair are 92 light years away and when we put the brightness of the two stars together they appear in the sky as a single star to the naked eye as a star of magnitude 3.6.
To the left of zeta is eta is a star of magnitude 4.0 and is 168 light years away, It is a B9 class star with a surface temperature of 11,000 degrees ‘ C twice the temperature of the Sun.
Just to the right of zeta is pi the faintest of the water jar group of stars at magnitude 4.6, it is a B1 giant star with a temperature of 26,700’ C. Pi is 780 light years away.

Wednesday, 29 April 2020

Astrognome A-Z of Constellations # 3 Apus the Bird of Paradise

Apus - the Bird of Paradise - Circumpolar southern hemisphere
Another small faint constellation and a constellation that is not visible for Britain. Apus the bird of paradise was introduced to the sky in the 1590s by the Dutch astronomer and cartographer Petrus Plancius from the observations of Dutch navigators Pieter Keyser and Frederick Houtman, when they voyaged to the southern hemisphere. and first catalogued by Plancius in the late 16th century.
The name of the constellation is derived from the Greek word apous, which means “footless.” (Birds of paradise were at one point in history believed to lack feet). The Greater Bird of Paradise known in India had a magnificent white, yellow and red plumage but unsightly legs, which were cut off by the natives desiring to offer the white man only the attractive part of the bird. There are no myths associated with the constellation.
It is located near the south pole star, there are no bright stars in Apus, the brightest are αlpha Apodis has a visual magnitude of 3.8, it is a K class giant star which is cooler than our Sun. Alpha Apodis is approximately 410 light years distant.
The second brightest star, Gamma Apodis has a visual magnitude of 3.9. It is a yellow G-type giant star slightly cooler than the Sun, it is approximately 160 light years distant.
Here is an example where the brightest stars do not follow the order of the Greek alphabet, with beta at magnitude 4.2 being fainter than gamma.

Tuesday, 28 April 2020

Astronomy in Yorkshire # 15 Observatories with Cooke Telescopes

Observatories with Cooke Telescopes

I know I am often going on about how good Cooke telescopes are and depending on your nationality you might have a different view. The American would go for Alvan Clark telescopes while the Germans would say that Zeiss telescopes were superior, but I always believe the best were Cooke telescopes.

I came across this interesting little survey from 1866 and while it does not claim to exhaustive it is fascinating. I could not believe these facts when I first saw them.

The survey was of 48 private observatories in Britain and indicated that 40 had refractors while only 8 had reflectors, an interesting fact in itself and showing how popular refractors were compared to reflectors.

Of those 40 surveyed

12 were equipped with Cooke telescopes

The next nearest telescope makers with just 3 were Alan Clark (USA), Troughton, Goddard, Slugg and Slater.

Although this list does not suggest to be complete it does give an indication of how popular Cooke telescopes were.

Astrognome A-Z of Constellations # 2 Antlia

Antlia the Air Pump – Spring Sky
The French astronomer Abbe Nicolaus de la Caille (1713-1762) is frequently encountered in connection with certain constellations in the southern sky. He travelled to the Cape of Good Hope in 1750 to chart the southern heavens and in 1763 produced a catalogue of over 10,000 stars which was published posthumously. In this list of stars he introduced 14 new constellations to the sky, sadly they are all faint and obscure groups and many of them represent what were at the time modern instruments. Hence the air pump rather than a classical Greek term.
There was originally 48 constellations the number has now increased to 88 many of these modern constellations are made up of faint stars just to fill in the gaps between the main constellations. Many do have modern sounding names.
The air pump was created to honour Robert Boyle’s invention of the air pump around 1660.
Antlia can be seen very low in the sky during spring evenings however there are no bright stars in the constellation, you would need a very clear southern horizon and a very clear sky to be in with a chance of seeing any stars in Antlia.
The brightest alpha is at mag 4.2 and has a spectrum of K4 giant star its surface temperature is around 3,800 degrees much cooler than our Sun and lies about 370 light years away. Even from the southern hemisphere where is is naturally much higher in the sky there is little to remark about Antlia.

Monday, 27 April 2020

Astrognome A-Z of Constellations # 1 Andromeda

Andromeda – autumn sky
We start our tour of the constellation with a fairly easy one to find and is involved in probably the most famous mythological story.
Andromeda is the princess linked with the story of Perseus and the Medusa plus Cassiopeia, Cepheus and Cetus (Kraken). Andromeda is depicted chained to a rock, however needless to say the pattern is nothing like a princess.
In mythology Andromeda is the daughter of queen Cassiopeia and King Cepheus, Cassiopeia boasted that her daughter was more beautiful than the Nereids these were 50 charming daughters of Nereus the wise old man of the sea. This was a decidedly tactless thing to say, offended by Cassiopeia’s remarks they complained to their protector the sea god, Neptune.
In anger Poseidon struck the water with his trident flooding the lands of the Palestine coast and calling up from the deep the sea monster the Kraken or Cetus. (There could be a basis in truth here because the great flood could have been caused by a meteor strike 3,700 year ago in the Eastern Mediterranean. The meteor crashed into where Austria is found but chunks could have fallen off into the sea causing the flood).
Cepheus consulted the oracle as to how to save his kingdom and was told that his land could only be saved if his daughter Andromeda was sacrificed to the monster. Accordingly Andromeda was chained to rocks near Joppa. Jaffa is the modern name for (Joppa) The name Joppa appears for the first time in the list of cities that Thutmose III captured (15th century BC). The legend of Andromeda being bound to the rock was first associated with Joppa by Strabo (1st century A.D.).
With Andromeda chained to the rocks and the monster appearing everything seemed lost, however at the very last minute Perseus riding the winged horse Pegasus appeared on the scene. He had just killed the Medusa. Anyone looking at Medusa would turn to stone. By chance Perseus still had the head of the medusa with him, he showed it to the monster who turned to stone. Perseus then landed and rescued Andromeda. They were married and lived happily ever after. All these characters can be found in the night sky.
For some reason in 1930 the International Astronomical Union the controlling body of world astronomers decided to move one of the stars from the square of Pegasus to the neighbouring constellation of Andromeda. Therefore Delta Pegasi whose name is Alpheratz and was the top left hand star of the square became alpha Andromedae. The other main stars in Andromeda are marked by a rather irregular line from the square of the Pegasus pointing towards the left to the constellation of Perseus. In order they are alpha or Alpheratz, delta, Mirach or beta, and Alamac or gamma.

Starting with alpha or Alpheratz or sometimes Sirrah which means the Horses Navel and clearly has nothing to do with a maiden chained to a rock is a star of magnitude 2.0 which means it is as bright as the North Star. The star is a B9 class star which means that with a surface temperature of around 13,500 degrees it is hotter than the Sun which has a surface temperature of only around 5,800 degrees, Alpheratz it lies about 97 light years away.
The next star on this line moving left from the square of Pegasus is delta Andromedae, it’s a K3 giant star which means it is not as hot as Alpheratz , it lies about 105 light years away. The star is fainter than Alpheratz being of mag 3.3 and its temperature is 4,000 degrees. It looks orange in colour.
Beta Andromedae or Mirach which means girdle, is next and is at mag 2.0 the same brightness as Alpheratz but at 200 light years away is actually brighter. It is an M0 giant star with a surface temperature of around 3,500 degrees which means that it is the coolest stars in this line. It looks more red than orange.
The final star in this line is gamma, whose name is Almach which means a small animal like a badger. Almach is about 350 light years away. It is at mag 2.1, the main star is K1 giant star with a surface temperature of 4,200 degrees.
Beta or Mirach can be used as a guide to find the Andromeda galaxy (M31). A line drawn upwards and slightly to the right from the star Mirach leads to the faint star Mu magnitude 3.9 then continue the line slightly further along to Nu magnitude 4.5. The Andromeda Galaxy is close to Nu slightly to the right. You will need a very dark site but it can be seen with the naked eye, if you know where to look. It is not spectacular with the naked eye but there is always the satisfaction of seeing the most distant object to be seen without optical aid. It is about 2.2 million light years away. It is larger than our galaxy and in about 3.5 billion years’ time the two galaxies will pass through each other!!.
A pair of binoculars will show it easily as a fuzzy patch in the sky.
Other stars you might try to find in Andromeda
Epsilon Andromedae is just below delta and is magnitude 4.4 and is 155 light years away. It is a G class giant star our Sun is also a G class star, however while the Sun is a dwarf star it will be slightly hotter than epsilon
Continue the line from delta through epsilon and further downwards and you will reach zeta Andromedae which is classified as an orange K-type bright giant with a magnitude of 4.1. It is cooler than our Sun and zeta is about 180 light years away.
Just to the left of zeta is eta Andromeda at magnitude 4.4 it is slightly fainter than zeta. It lies 240 light years away and is another G class giant star.
Located just above delta is pi Andromedae at magnitude of 4.4 and is located approximately 600 light-years from Earth. It is a B class dwarf star meaning it is much hotter than the Sun.
Groombridge 34 - One of the closest double stars to Earth at 11.7 light-years distant. Although not bright or spectacular Groombridge 34 is an interesting double since it consists of two red dwarf stars in near circular orbit. The two stars shine at magnitudes +8.1 and +11.1 far too faint to be seen with the naked eye. They are easily within the range of medium size telescopes. In August 2014, a planet orbiting Groombridge 34 was discovered.

Sunday, 26 April 2020

The Astrognome A-Z Guide to the Constellations - Introduction

Starting tomorrow I will take you on my A-Z of the constellations, but first here is hopefully a simple introduction to the stars we see in the sky.

There appears to be millions of the stars in the sky around us on a clear night, surprisingly on a good clear night it is possible to see not millions but around 3,000 stars from from any one place on the Earth. They appear to be randomly spread around the sky but they are grouped together in 88 patterns or constellations which tell the stories from ancient mythology. In the west we tend to use the stories from ancient Greece, but while the constellations are Greek most of the star names we use are Arabic, which is why they can sometimes seem a little bit different to us.

Some stars we can see all year round while some we can only see in certain seasons. We know the Earth takes a year to go once around the Sun and we only see the stars at night time. But the stars are in the sky in the day time as well, we can’t see them because the Sun is simply too bright. This means that if it is summer we see the summer stars in the night sky while at the same time in the day sky there would be the stars that we would see in winter in 6 months time. Which ever of the 4 seasons we are in, the opposite season stars are in the day sky.

I mentioned that we can see some stars throughout the year, this is because we need to think of the Earth in space in a 3 dimensional way (sorry I don’t want to go into heavy astronomy) however where ever the Earth is in its yearly orbit around the Sun there will be stars above and below us that will never set, these stars are called Circumpolar Stars and this applies to both the northern and southern hemispheres. The most famous of the northern circumpolar groups of stars is the Plough or as the Americans like to call it the Big Dipper.

This is a simple guide to the 88 constellations in the night sky which can be seen without using telescopes or binoculars. It always seems daunting at first to navigate around the night sky but once you are able to find certain signposts in the sky it becomes relatively simple. There are so many star maps that can be downloaded on to mobile phones, i pads or laptops that can act as an aid to navigating around the sky.

Here are the 88 constellations.

Latin Name
English Name or Description
Princess of Ethiopia
Air pump
Bird of Paradise
Water bearer
Graving tool
Canes Venatici
Hunting dogs
Canis Major
Big dog
Canis Minor
Little dog
Sea goat
Keel of Argonauts' ship
Queen of Ethiopia
King of Ethiopia
Sea monster (whale)
Coma Berenices
Berenice's hair
Corona Australis
Southern crown
Corona Borealis N
orthern crown
Cross (southern)
Little horse
Hercules, son of Zeus
Sea serpent
Water snake
Leo Minor
Little lion
Lyre or harp
Table mountain
Carpenter's Level
Holder of serpent
Orion, the hunter
Pegasus, the winged horse
Perseus, hero who saved Andromeda
Piscis Austrinis
Southern fish
Stern of the Argonauts' ship
Pyxis (=Malus)
Compass on the Argonauts' ship
Sculptor's tools
Triangulum Australe
Southern triangle
Ursa Major
Big bear
Ursa Minor
Little bear
Sail of the Argonauts' ship
Flying fish

The 88 constellations are made up of 48 that date back to the times of the Greek astronomers 2,500 years ago and are found in the northern hemisphere while the other 40 are considered ‘modern’ in that they were mostly created in the 16th and 17th centuries when explorers travelled to the southern hemisphere and saw stars that no one knew about and then designed ‘new’ constellations. These often depicted new scientific instruments such as the telescope and microscope. Unfortunately many of these groups are very faint and obscure. In the northern hemisphere astronomers tried to fill gaps between the original constellations, again many of these ‘modern’ constellations are faint and obscure and many hardly warrant a mention.

The brightness of stars are measured using a magnitude scale and rather confusingly the lower the number the bright the star. A star of magnitude 1 is much brighter than a star of magnitude 6, which are the faintest stars that can be seen with the naked eye under the very best of conditions. In towns and cities magnitude 4 is usually the best that can be seen due to light pollution. Stars which have a minus number are the very brightest stars. The brightest star we see in the night sky is Sirius the Dog Star at magnitude -1.44 it is a winter star and is in the constellation of Canis Major the Large Dog.

The 24 brightest stars of each constellation is allocated a letter from the Greek alphabet, this system was introduced in 1603 by the German astronomer Johann Bayer. In theory the brightest star in a constellation will be alpha then beta until omega, but sadly it does not always work that way!! Astronomers use the lower case to identify the stars rather than capital letters.

Greek Alphabet

The colours of stars tell astronomers which ones are hotter or cooler in nature. Stars that are blue or white in colour are much hotter than red stars. Our Sun being yellow is about mid range. This does seem strange when we say that things can become red hot, but if you look at a flame the red or orange part is around the edge while in the middle the colour is bluish, the hottest part of the flame. And while stars don’t burn like fire the colours are produced by atomic reactions the colour theme is the same as a flame.

Saturday, 25 April 2020

Astronomy in Yorkshire # 14 A Yorkshire Telescope in Shrewsbury

A Yorkshire Telescope in Shrewsbury

James Cavan died on April 25th 1911, he was born in London in 1856 and educated at Harrow and Christ Church Oxford.

Throughout his life he had a keen interest in astronomy and at his county seat at Eaton Mascott Hall, Shrewsbury he built a well equipped private observatory with a 7.5 inch photo visual Thomas Cooke telescope (Cooke photo visual lens were made after 1894).

Most of his life was devoted to the public business of the county of Shropshire.

Cooke 7.5 inch

Wednesday, 22 April 2020

Astronomy in Yorkshire # 13 April 22nd 1903 Another Bright Meteor Seen Over Huddersfield

Another Bright Meteor Seen Over Huddersfield

On April 22nd 1903 Mr C L Brook at Meltham near Huddersfield, saw a greenish fireball which lasted for 3 seconds. It exploded twice like a flash of lightning.

The fireball seemed to explode at about delta Cepheus and to have been directed towards alpha Cepheus.

After falling for about 6 or 7 degrees it burst out again with a beautiful greenish light and exploded into a sort of nebulous halo.

Tuesday, 21 April 2020

Astronomy in Yorkshire # 12 April 21st 1901 Bright Cassiopeid meteor seen over Huddersfield

Meteors over Huddersfield

On the night of April 21st Mr C L Brook of Meltham near Huddersfield counted between 40 – 50 meteors including a number of Lyrids.

But the most interesting meteor observed at many stations including Meltham was that of a bright Cassiopeid which came into view at 11hr 22m. Its radiant point was near delta Cassiopeia and it descended from 66 to 44 miles over a path of 55 miles. It is remarkable that slow moving fireballs often take their flights from this radiant near delta Cassiopeia in the spring months of April and May.

Fireballs had been seen on April 2nd 1891, April 9th 1876, April 10th 1874, April 15th 1893 and May 30th 1877. There were various meteor catalogues from observers containing other brilliant instances of bright slow moving April meteors from the same radiant in Cassiopeia.

Monday, 20 April 2020

Astronomy in Yorkshire # 11 April 20th 1902 bright meteor seen over Bradford

April 20th 1902 bright meteor seen over Bradford

On April 20th 1902 Mr G. Fisk of Ecceshill, Bradford saw a large meteor brighter than Venus. It appears to have travelled from alpha Draco and disappeared near gamma Ursa Minor.

Intensley blue in colour and the meteor cast a shadow, though the Moon was nearly full. The duration of the meteor was 1.5 seconds. It was not a Lyrid.

Ed Note the star alpha Draco whose proper name is Thuban was at the time of the building of the great pyramids in Egypt the North Star. The position of the North Star changes over a period of thousands of year due to the Earth wobbling slightly on its axis.

The annual Lyrid metoer shower peaks every year on the night of April 21st/22nd. The fact that Mr Fisk says it is not a Lyrid suggests that he had a knowledge of the night sky and knew about meteor showers.

Bright Meteor

Sunday, 19 April 2020

Astronomy in the North West # 9 Joseph Baxendell 1815-1887

Joseph Baxendell 1815- 1887

Joseph Baxendell

Joseph Baxendell was born on April 15th 1815 at Bank Top, Manchester. He was a sickly child and at the age of 14 his father sent him on a ship to Valparaiso, Chile, for the fresh air that would ais his health. It must have worked because he made several other trips to South America and in 1833 while in Central America he saw the Leonid meteor shower on the night of November 12th/13th when around 240,000 meteors were seen, this started his great interest in astronomy.

Leonid meteor shower 1833

Following his trips to South America he settled back in Manchester and with his friend Mr Robert Worthington of Crumpsall Old Hall they erected the Crumpsall Observatory which housed a 13 inch Reflector, Baxendell cast, ground and polished the mirror. In 1859 he was appointed Astronomer to the corporation of Manchester. In 1863 he was elected president of the Literary and Philosophical Society of Manchester. 

As far as I can discover Baxendell discovered around 20 new variable stars including a joint discovery in 1866 of T Corona Borealis the famous Blaze Star, the first of the recurrent nova, the star would go nova again in 1946.

Map showing T Corona Borealis on lower left

He also took a great interest in the study of meteorology and produced many papers in the study of this science.

In 1871 Baxendell was appointed the first superintendent of a new meteorological station located in Hesketh Park, Southport. In 1877 the polymath Thomas S Bazley who also had a great interest in astronomy donated a 6 inch Cooke telescope to Baxendell. This would allow him to continue his variable star work. The telescope cost £365 when it was purchased in 1867. Bazley also supplied the timber structure for the telescope. Baxendell renamed his house at 14, Liverpool Road, Birkdale, The Observatory.

Baxendell's Observatory was orginally the top wooden part, this is the observatory in  Hesketh Park c 1927

Being a devout Methodist Baxendell had the first line from Psalms chapter 19 from the King James Version of the bible painted around the base of the dome “The Heavens Declare The Glory Of God , And The Firmament Sheweth His Handiwork”

Joseph Baxendell died on October 7th 1887, his observatory was donated by his son in 1901 to the education department of Southport Corporation where it was rebuild upon a brick base in Hesketh Park with funding provided by John Fernley, The observatory can still be seen there today with its Cooke telescope.

Friday, 17 April 2020

Astronomy in the North West # 8 April 17th 1873 John Stanistreet Liverpool Navigator and Horologist

John Stanistreet

A native of Liverpool he was the son of an eminent solicitor. He had great interest in science and mechanics but sadly his health was never strong. He decided to follow his father’s profession as a solicitor. The family firm became one of the top solicitors in Liverpool. They were involved in negotiating some of the largest land sales in the commercial city of Liverpool.

Due to a problem with his lungs he spent the winter 1840 and 1841 on the island of Madeira where the air was cleaner. While travelling by ship he gained a great interest in navigation and the positions of the stars. He spent some time travelling to the Greek island and impressed the captains of ships with his navigational skills due to knowing the positions of the stars.

In 1851 he travelled to Sweden with his friends William Lassell and George Williams (see North Western Astronomy News 07.04.20), to watch an eclipse of the Sun, he travelled to Spain in 1860 to see another but the weather was cloudy.

His health continued to decline and he was forced to withdraw from the family business. He decided to converted a dressing room at his house as a laboratory.

It was hear that he made the Stanistreet A1 clock which was described and figured in the English Mechanic of March 1872. The smallness and the regularity of rate of the A1 in very unequal temperatures was really a marvel. The clock was as good as any that were used at the Royal Observatory. I don’t know if the Stanistreet A1 clock still exists and if it does its location.

Sadly John Stanistreet’s health continued to decline and sadly he died on April 17th 1873