Sunday 27 September 2020
Saturday 26 September 2020
Epsilon Auriga is a noted eclipsing binary, it is the star that forms the apex of the small triangle of stars that form the Kids just below Capella the brightest star in Auriga. Capella is known as the She Goat Star so wherever Capella goes the kids will always follow.
Epsilon or to give its proper name Almaaz which means the ‘Billy Goat’, is a F0 supergiant with a huge companion of some unknown type. The eclipse is massive and about every 27 years Almaaz fades from magnitude 2.9 to 3.8 it stays like this for between 640-730 days.
The first recorded fading of the star was in 1821, however it was only in 1912 that astronomers realised how extraordinary the eclipse is.
The nature of the Almaaz system is still a mystery to astronomers, one suggestions is that the companion star might be an enormous yellow supergiant star. Astronomers are not even sure how far away Almaaz is with estimates from 1,000 to 1,350 light years away.
The last eclipse was in 2009-2011 with the next eclipse predicted to occur around the year 2037.
Friday 25 September 2020
Thursday 24 September 2020
Alpha Ursa Majoris or Dubhe is the northern most of the two pointers that indicate how to find the North Star. Although designated alpha it is actually the second brightness star in the constellation. The name Dubhe means the ‘Bear’ in Arabic.
Dubhe has a magnitude of 1.8 and is a K0 orange giants tar with a temperature of around 4,600 degrees lying at a distance of 123 light years. Dubhe is not part of the Ursa Major Moving Group of stars which consist of 14 stars of which 13 are located in Ursa Major.
Dubhe has a close companion star which orbits around it every 44 years but its a very difficult star to see without a large telescope. Dubhe has been suspected of being a variable star. In 1867 the German astronomer H J Klein thought the star showed changes in colour from reddish to yellow. In 1881 it was suggested that the star varied in brightness with a period of 54 days. Today astronomers believe that any light variations are very small indeed.
An Observatory for Stockport
On the 24th September 1860 the foundation stone for an observatory at Vernon Park, Stockport was laid. The observatory was to be designed on the English period of Gothic style.
The observatory will be divided into 8 chambers the top storey will be used for astronomical purposes.
The building will be made of the best hard red and white bricks with Hollington stone for the windows and dressings. The staircase will be of hard Yorkshire stone. The top of the tower will be open but protected by a light ornamental iron railing. The height of the building will be 160 feet and the cost will be £1,000.
Sadly the funds for the tower were not raised so this potentially fine observatory for Stockport was never built.
Wednesday 23 September 2020
On December 13th 1934 J P M Prentice an English astronomer discovered a nova in the constellation of Hercules. It would brighten until on December 22nd it reached a maximum brightness of magnitude 1.5 making it the brightest star in the constellation of Hercules.
The word nova comes from the Latin for new, in the middle ages when astronomers saw a new star they thought it was a star being born and called it a nova, we still use this term today.
We now know that a nova is a binary system there are two stars one a small hot massive star the other a larger but less massive star. The small star pulls gas off from its companion and this cool gas forms a disc around the smaller hotter star, eventually this gas will cascade down onto the hotter star. As this gas is cooler it makes the hotter star ‘sizzle’ and it will throw off a shell of gas into space.
This gas which represents only about 0.1% of the mass of star but causes a faint star which normally cannot be seen without a large telescope to appear visible to the naked eye. Of course not all nova become bright enough to be seen with the naked eye.
DQ Hercules appeared at a time when astronomers were trying to work out the difference between ordinary nova and nova that appeared very bright, these would of course be termed Supernova and this term would first be used by the Swiss astronomer Fritz Zwicky at around this time.
The Cooke 25 inch Telescope and Capella
In 1870 the Newall telescope which had beem made by Thomas Cooke and Sons of York and had a lens 25 inches across was installed in the observatory of Robert Newall in Gateshead. Following the death of Robert Newall in 1889 the telescope was sent to Cambridge and was used by Hugh Newall the youngest son of Robert.
In 1899 using the 25 inch Hugh Newall with a 4 prism spectroscope observed that the star Capella the brightest star in the constellation of Auriga the Charioteer was a binary star.
In America during 1899 Prof William Wallace Campbell at Lick Observatory also noted that Capella was a double, this was based on photographs taken between 1896-1897.
Tuesday 22 September 2020
In a bright constellation such as Orion a star which shines at magnitude 2.0 would not really attract any attention but Deneb Kaitos or Diphda which means the ‘Frog’ is actually the brightest star in the constellation of Cetus the Whale.
Cetus is a large but difficult to identify constellation due to the number of faint stars. With a magnitude of 2.0 Deneb Kaitos is a bit of a search light in the constellation. It is a K0 orange giant star with a temperature of 4,700 degrees and lies at a distance of 97 light years.
But what makes it so interesting for an old star is that it is a very strong source of X rays while normally older stars produce fewer x rays and astronomers are not quite sure why.
Dusky Spots on Jupiter seen from Manchester
On September 22nd 1870 Mr Ormesher of Manchester observed at 5.15 am using his 5.25 inch refractor saw 3 dusky spots on the disk of Jupiter, they were situated on the upper large belt and seemed to convey the impression that Jupiter’s atmosphere was much disturbed.
Mr Ormesher also saw 3 dusky spots on Jupiter at 5.00 am on July 23rd 1870 using his 5.25 inch refractor.
Monday 21 September 2020
Edward Arthur Milne 1896- 1950
Edward Arthur Milne was born in Hull, East Yorkshire on February 14th 1896, he was known for carrying out pioneering research into atomic physics.
E A Milne was educated at St Mary’s Church of England School, Salterhouse Lane, Hull before going to Hymer’s College in Hull. In 1914 he entered Trinity College Cambridge. Poor eyesight meant that he could not go into active service but in 1916 he joined the anti aircraft section of the Munitions Inventions Department.
In 1919 he returned to Cambridge and in 1928 he was Beyer professor of applied mathematics at the University of Manchester he delivered the Halley lecture in 1932 on White Dwarf Stars. In 1935 he was awarded the gold medal of the Royal Astronomical Society. E A Milne became Rouse Ball professor of Mathematics at the University of Oxford in 1928.
His research included atomic physics, meteorological physics, and solar and stellar physics in particular stellar atmospheres and the structure of the Sun and stars.
E A Milne died in Dublin on September 21st 1950 on his way to a colloquium in the rooms of the Royal Irish Academy
The Astronomy Show
Join me, Martin Lunn tonight from 7.00 pm-9.00 pm on the Astronomy Show, I will take my weekly look at the night sky and look at all the latest news in astronomy. There will be the astronomical anniversaries this week plus the A-Z of Constellations and the Messier Marathon.
The Astronomy Show every Monday evening only on Drystone Radio 103.5 FM the show can be heard live on line at www.drystoneradio.com and the show can be heard later on the Drystone Radio Podcast.
Sunday 20 September 2020
A Cooke in Camden Square
On September 20th 1865 John Lampray of Camden Square London purchased a 2.25 inch OG in its cell with a focal length of 45 inches Frome Thomas Cooke and Sons. He later purchased a larger 4.5 inch Cooke and Sons telescope.
My next reference to him comes in 1884 when the 4.5 inch together with its observatory was advertised for sale. The observatory was described as being in an excellent condition with a revolving dome covered in zinc with a sliding shutter.
I do not know if the telescope and observatory were being sold due to the death of John Lampray or whether he was unable to use the telescope. Astronomers in London might know.
Saturday 19 September 2020
Starting Astrophotography and High Latitude Novae
When not posting historical information I am often found making naked eye observations of the night sky. Starting last century I have spent many years using 15x70 binoculars looking for high latitude novae. These are novae that occur between 3-4 kpc above or below the galactic plane. However I have been pushed by some of my friends to enter the 21st century and at least take some photographs. I must stress that I am a non expert when it comes to photography as you will see from the example with this blog.
I have recently been checking the area between Ursa Major, Lynx and Camelopardalis which I know appear quite barren, they are among the areas that don’t attract much attention. I should point out that in the many years of observing I have come close to but have yet to discover a nova.
I consider myself a techno pagan so this was a big step, I have just purchased a second hand skywatcher tracker and a Fuji X-T2 camera, although I think I got the wrong lens because I got a 135 mm with a small field of view when a wider field would have been more useful. I will have to rectify this.
My first pictures which I took on 17.09.2020 will not win any competitions but they are not intended to. What they allow me to do is to look for novae or notice variable stars that are behaving out of their normal behaviour. I check my photos as I would check my visual work by using Sky Map Pro 12 which I find is rather good, I find going down to magnitude 9.0 is perfectly adequate for me.
I have shown an example of my first photographs of the Kids, I was using Capella as a target, the tracking still has to be worked on! I cannot resist mentioning that while trying to photograph the area around beta Ursa Minoris or Kochab I completely missed and ended up photographing the area around kappa Draconis which is equally interesting.
Friday 18 September 2020
Denebola or beta Leo its name means the ‘Tail of the Lion’ is not only the 2nd brightest star in Leo it is also the 2nd brightest star in the zodiac. Denebola forms a distinctive triangle of stars with delta and theta, Denebola shines with a magnitude of 2.1 and is an A3 class star with a temperature of around 8,500 degrees which is hotter than our Sun. The star lies at a distance of 36 light years.
Denebola is a young star and astronomers believe that it is only around 400 million years old. This is interesting because astronomers in ancient Greece always ranked Denebola as being of the first magnitude and they said it outshone Regulus which is the brightest star in Leo today. This might be another star that has faded over a very long period of time. It is often listed as a possible variable star.
Some sources suggest that Denebola is a delta Scuti type variable star these are young stars that pulsate and change only slightly in brightness and only a very experienced variable star observer would notice the change in brightness without special instruments. Having said that this could be an example of a delta Scuti type star that has changed in brightness over a much longer period than astronomers can measure today using the latest equipment.
Thursday 17 September 2020
Cygnus the Swan is one of the most striking of all the constellations. It is often nick named the ‘Northern Cross’. Its 5 main stars are arranged in an X pattern.
The brightest star in Cygnus is Deneb, which means The Hen’s Tail, and forms with Altair in Aquila and Vega in Lyra the summer triangle of stars. Although appearing to be the faintest of the three stars it is actually the brightest.
Let me explain although when we look at the summer triangle Vega looks the brightest then Altair and thirdly Deneb. However appearances can often be deceptive, because Vega is 25 light years away while Altair is only 17 light years away but Deneb is a whooping 2,500 light years away. If all three stars were placed on a line the same distance from the Earth then Deneb would massively outshine Altair and Vega.
Deneb lies in a rich part of the Milky Way and near it is one of the most interesting nebulas in the northern hemisphere, this is the North American Nebula and it does look like North America and is a favourite with astro photographers. It can just be seen with the naked eye but only as a slightly bright patch in the sky.
John Goodricke 1764-1786
This is the story of one of the most unusual astronomers of all time. His name was John Goodricke and he was deaf and unable to speak. He would have a tragically short life but his contribution to astronomy would be immense.He was born in Groningen in Holland on September 17th 1764 to Henry and Levina Goodricke. The Goodricke family were a typical English aristocratic family with their ancestral home being at Ribston Hall near Knaresborough in North Yorkshire.
His grandfather Sir John Goodricke was the powerhouse of the family and achieved some importance within political circles. When he heard of the birth of his grandson he was most pleased, but turned to dismay when shortly afterwards it was realised that the infant was deaf. There was a very strong stigma imposed on disabilities within the aristocracy at that time.
In the early 1770s the Goodricke’s returned to England to York, the young John Goodricke was sent to Edinburgh to a school run by Thomas Braidwood for deaf children. We have little information of this part of his life, it is possible he learnt to lip read, sign language had not yet been devised. In 1778 he was sent to the Warrington Academy which had no special provisions for children with special needs.
It was here that he developed a great interest in mathematics, science and in particular astronomy. He left the Warrington academy in 1781 and returned to York to live in the Treasurers House near York Minster. It was here that his astronomical career would begin. He began his astronomical journal on the 16th November 1781.
A year earlier a distant cousin who was also an astronomer would also move to York, this was Edward Pigott. Edward Pigott lived with his father Nathaniel yet another astronomer at what is now No. 33 Bootham in York, the house still survives today is where William Arthur Evelyn (1860-1935) a pioneer of conservation in York lived.
Together John Goodricke and Edward Pigott they would forge an astronomical partnership that would push back the frontiers of astronomy. They would not only make discoveries but like true scientists they would try to explain them.
They were an odd couple, Goodricke a deaf youth of just 17, with his older cousin Pigott who had spent much of his life living in France and like to dress up French style. This was much more flowery than the more conservative English style. Today Pigott would have been described as a ‘dandy’
The only reason that the Pigotts were in York was that Nathaniel Pigott who was a distant cousin of Lady Anne Fairfax of Gilling Castle in North Yorkshire was trying to swindle her out of her inheritance! Edward played no part in this.
The two astronomers come together in 1781 just a few months after William Herschel discovered the planet Uranus from his home in the city of Bath. The scientific community was abuzz with all things astronomical.
They quickly began observing the sky, the Pigotts observatory has been described as the 3rd best private observatory in England while Goodricke used a small telescope at the Treasurers House.
They knew of a star in the constellation of Perseus that was called Algol, its official title is Beta Perseus, as far back as 1669 astronomers had noticed that it changed in brightness. It is what astronomers refer to today as a variable star because it varies in brightness. The world Algol means ‘The Winking Demon’ as this star marks the eye of the medusa from Greek mythology.
Goodricke observed the star and recorded that it remained at its brightest for 2 day, 20 hours, 48 minutes and 56 seconds, then it fades away for about 10 hours then recovers to it normal brightness. We know that today Goodricke’s observations are within a few seconds of modern estimates. This was of course using just his eye and a clock.
Interestingly because Goodricke was deaf a servant used his finger to mark out the beat of the clock to accurately work out the time. Even now we can see how the mind of Goodricke was working because although he knew that Pigott was making observations of Algol from his observatory in Bootham Goodricke knew that if Pigott was using the chimes of the bells in York Minster to check the time it would take an extra half a second for the sound to reach Pigott.
Goodricke in particular and Pigott both assumed there was another body orbiting Algol and blocking the light, and they were of course correct. They believed that it could be a planet, we know today that it was another star. However the idea that a planet can change the amount of light we see from another star is one of the ways that astronomers use to discover planets around other stars. They were over 200 years ahead of their time in thinking.John Goodricke was only 19 in 1783 when he wrote to the Royal Society about his observations and thoughts on Algol. He was unknown was deaf unknown outside of York, but Edward Pigott was good at networking and he knew anybody of importance in astronomy. He contacted his friend Nevil Maskelyne the astronomer royal explained what was happening and Goodricke’s work was published.
The effect on the astronomical community was electrifying, all over the country people were observing Algol, Goodricke was awarded the Copley medal by the Royal Society the highest award they could give.
If Goodricke and Pigott had stopped here they still would have made a remarkable contribution to astronomy, this was just the start they were not going to stop now.
The 10th September 1784 would become a night to remember in York, with not just one but two new variable stars being discovered, they were by Goodricke Beta Lyra in the constellation of Lyra (the Lyre) and from Pigott eta Aquila in the constellation of Aquila (the Eagle).The indefatigable Goodricke would discover another variable star on October 24th this was delta Cepheus in the constellation of Cepheus (the King). This star is of immense importance today it is used a distance marker because it allows astronomers when locating these so called Cepheid variables to determine how far away distant galaxies are. Goodricke could of course never know of the importance of this star.
These discoveries were due to their complete knowledge of the locations of stars in the sky by continuously observing the night sky.
More reports were sent to London, the astronomers there must have wondered what on earth was going on in York!Although Goodricke he did not know it his short life was nearly over, he died on the 20th April 1786 probably from pneumonia caught while observing the night sky. During the 1780s the river Ouse in York regularly froze over for up to 6 week each year giving an indication of how cold it was. He was made a fellow of the Royal Society a most prestigious honour for someone so young. Sadly he died two weeks before that letter arrived so he never knew of that honour.
Wednesday 16 September 2020
Delta Orionis or Mintaka is the western most of the three stars that form Orion’s Belt and therefore it rises or draws Orion’s belt across the sky. Mintaka which in Arabic means the ‘Belt of the Central One’ lies very close to the celestial equator.
Mintaka lies around 1,200 light years away and shines with a magnitude at 2.2, its a triple star system. The star we see with our eye is an 09 blue/white giant with a surface temperature of 29,500 degrees much hotter than the Sun at only 5,800 degrees.
There are two other stars that complete the Mintaka system, and these are both B class stars which are hotter than the Sun, although not as hot as Mintaka.
We know that the North Star changes duie to the wobbling of the Earth over a very long period of time and due to this wobbling in 2054 Mintaka will lie exactly on the celestial equator.
Cookes and the Mayflower
Scientific Instruments made by the York based company Cooke Troughton and Simms were sent across the Atlantic Ocean on board the Mayflower 2.
The Mayflower 2 sailed on April 20th 1957 from Plymouth in Devon replicating the original voyage of the Mayflower in 1620. The Mayflower 2 arrived in Plymouth Massachusetts on June 22nd 1957 and was then towed to New York City on July 1st 1957.
The instruments were placed in a treasure chest where when it arrived in New York City was greeted by President Eisenhower. It then became a tourist attraction with its treasures including the Cooke Troughton and Simms instruments being seen by tourists.
The instruments which were inscribed to commemorate their method of transport will eventually be taken by the company’s representatives in the cities of Boston, Chicago, and the states of California and Colorado.
Monday 14 September 2020
Meteors seen over Manchester same area different years
The Great Detonating Meteor seen from Manchester
On September 14th 1875 at 8.27 pm Mr T W Grey reported the meteor. He said ‘The nucleus appeared to be of about two thirds that of the moon, the colour resembling the magnesium light, the tail apparently 2 or 3 yards in length, of a ruddy colour: the part immediately in contact with the nucleus resembled ordinary fire. I heard no noise. The head was excessively bright. I first saw it very near to the moon, whence it proceeded in a northerly course, parallel with the Earth’s surface and about 60 degrees above the easterly horizon. Its speed for a meteor was slow. It remained in sight for 7 seconds, until it disappeared behind the houses’
position 348 degrees +0 near beta Piscium
The Fireball of September 14th 1901 seen from Manchester.
On September 14th at 8.44 pm an unusually bright object was seen in the sky and was witnessed over a large part of the country.
Mr J Halton of Manchester says the nucleus seemed to plough its way through the atmosphere as though strongly resisted.
The meteor was estimated as being as bright as the full moon. The radiant point of this bright meteor was very similar to that of September 14th 1875 also seen from Manchester.
position 345 degrees +1 degree
Sunday 13 September 2020
This is one of the most famous and important stars in the sky. Delta it has no name and was discovered to be variable by John Goodricke in York in 1784, Goodricke who was deaf and unable to speak was with Edward Piggot one the ‘Fathers of Variable Star Astronomy’.
Delta is the prototype for the Cepheid variable stars which astronomers use today to determine 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.
An interesting coincidence is that John Goodricke who discovered delta to be variable was deaf and Henrietta Leavitt who explained it was deaf in one ear.
Delta is about 887 light years away, its spectral class varies between F5Ib-G1Ib with a surface temp of around 5,500 to 6,800 degrees as it varies. The magnitude varies between 3.6 and 4.3 every 5 days and 9 hours. There is a companion star with a spectrum of B7-8 giant which orbits every 6 days.
A Cooke in Plonsk
On the death of Dr J Jedrzejewicz at the end of 1887 the observatory which he had founded at Plonsk was moth balled for a number of years. Plonsk is a town in north central Poland. The observatory which housed amongst other telescopes was a 5 inch Cooke with a clockwork drive. Jedrzejeewicz was a noted amateur astronomer in Poland and used to observe 16 comets, as well as sunspots, double stars and lunar occultations.
In 1886 he wrote ‘Kosmografia’ A Handbook of Astronomy.
In 1898 the observatory was rehoused at Warsaw at a location a short distance to the north west of the University there.
At present I have no further information on the observatory or Cooke telescope or even if it still exists.
Saturday 12 September 2020
Maurice Farman and the Chevreuse Observatory and Cooke
As far as I am aware this is the not the same Maurice Farman who was an early pioneer in the days of flight, but I am always ready to be proved wrong.
In 1908 while observing at the Chevreuse Obseravtory near Paris, an observatory I have never heard of before he observed 1,100 double stars while using a 9.5 inch Cooke telescope.
His observations were apparently quite brief and usually consisted of just one line of information, many additional notes were drawn from historical observations of the stars he observed in 1908.
The Crab Nebula is the remnants of a star that destroyed itself in what astronomers call a supernova explosion.
July 5th 1054 dawned peacefully, except that south of Zeta Tauri Chinese sources tell us that a bright star suddenly appeared where none had been before. It shone as brightly as the planet Venus in the sky.
One most interesting fact is that there does not appear to be any records from Europe. One suggestion was that the belief of the church was so strong and that monasteries were the centres of learning and the belief was that the heavens were unchanging so that even if a bright star appeared in the sky it would not have been reported. After about a year the star disappeared from view and nothing was seen of it for about 700 years.
It was in 1731 that the astronomer John Bevis and in 1758 Charles Messier while searching for comets recorded it and in Messier’s case began his catalogue of comet like objects which he drew up to avoid getting confused with real comets. The Crab Nebula became Messier 1 or M1, his list would eventually run to 110 objects.
The name Crab Nebula was introduced by Lord Rosse in 1844 while observing it a home made 36 inch reflector from Birr Castle in Ireland. He thought it looked like a crab. Strangely when he observed it again in 1848 he could not see the shape of the crab and yet the name has stuck.
At the centre of the nebula is a small neutron star about 20 miles across spinning at around 30 times a second. The crab nebula is one of the most heavenly studied objects in the galaxy. The nebula is expanding at a rate of around 930 miles per second.
The crab nebula lies at a distance of around 6,500,light years. It cannot be seen with the naked eye and shines with a magnitude of 8.4, which means it can be seen through binoculars.
Friday 11 September 2020
A Cooke in Manchester
I have come across details of a Cooke telescope which was purchased by Benjamin Dennison Naylor of Manchester in 1863 it was a 6 inch Cooke, I then came across a note from a Miss Naylor of Altrincham in 1869, following the death of Benjamin Naylor. I am not sure what relation she was to Benjamin but she was advertising a very fine equatorial by Cooke, almost new, 6 inch aperture with clockwork movement, eyepieces and finder.
Benjamin Naylor died at his residence at the Knoll near Altrincham on December 27th 1868, he was the last lineal male descendant of four of the clergy ejected from their livings by the act of Uniformity in 1662. He was a governor of Chetham’s Hospital and Library.
I do not know who brought this telescope following the death of Benjamin Naylor, maybe someone in the Manchester area is familiar with this astronomer and might know the answer.
Alpha Canes Venatici is the brightest star of the hunting dogs that was created by Johannes Hevelius in the 1670s. It is formed of stars that can be found beneath the handle of the Plough or Big Dipper as it is known as in America.
The name Cor Caroli is modern, the star in ancient Greece was known as ‘Chara’ one of the two hunting dogs. Beta Canes Venatici was known as ‘Asterion’ the second of the hunting dogs. Today we use Cor Caroli and there is some confusion what this refers to.
Cor Caroli means ‘Charles’ Heart’ and one legend says that it represents King Charles II when he was crowned king in 1660, it is said to have shone brightly that night. The other is that is represents King Charles I on the night he was executed when the constellation was seen pointing downwards in respect of the execution of the king.
It is a double star lying at a distance of 115 light years. The two components of the star are formed of an A0 and F2 class stars, the A class star is the brighter. Alpha 2 which is the star we see and call Cor Caroli is slightly variable varying between magnitudes 2.8 and 3.0 which can be detected by an experienced variable star observer.
Cor Caroli is a strange magnetic variable star and is made up of elements similar to those of Chi Lupi, It is in fact the prototype star for a whole group of these magnetically variable stars which spread between A and B class stars with Cor Caroli being in the middle.
Although it is beyond the scope of these notes astronomers study these Cor Caroli type variable stars to try to better understand if there is a link between them and white dwarf stars.
Thursday 10 September 2020
The constellation of Lupus the Wolf is squeezed between the constellations of Scorpio and Centaurus. Among its treasures is a modest looking star of magnitude 3.9, this is Chi Lupi which can be found just below the head of the scorpion.
Chi is a double star the two stars cannot be seen without using a spectroscope, they are separated by about 20 million miles and take 15 years to orbit each other. The main star is a B9 class star and its companion is an A2 star. Chi lies at a distance of around 210 light years.
What makes Chi special is that it is made of different stuff to what we would expect to find in most stars. The Sun for an example is an ordinary star and is made up of mostly of light materials such as hydrogen and helium.
With Chi Lupi we find heavier elements such as copper, zinc and mercury more abundant than astronomers find in other stars. At the present time sstronomers do not know why.
They are often referred to as metallic stars. Not because they are made of metal the star is too hot for the elements to exist in a solid state but because of the large amount of metallic materials in these stars.
September 10th 1784 A Night to Remember in York
John Goodricke and Edward Piggot formed an unlikely alliance when they met in York in 1781, because for 5 short years they would make York one of the astronomical centres of the world. Through their observations of the night sky they would earn the title of ‘The Fathers of Variable Star Astronomy’
John Goodricke was deaf and unable to speak and Edward Piggot who dressed in a very flamboyant style knew everyone worth knowing in the world of 18th century astronomy.
They had already observed and explained the light variations of beta Perseus or to give its name Algol, or the winking demon, they believed that there were two objects orbiting each other causing the regular light variations. This idea is used by astronomers today when they are looking for exoplanets around other stars, Goodricke and Piggot were nearly 250 years ahead of the game.
If they contributed nothing else to astronomy there achievements would be immense. Yet it was on the night of September 10th 1784 that a series of amazing discoveries would be made, up until this date only 5 variable stars were known to astronomers.
Yet on this night in York, Edward Piggot would discover the variability of eta Aquila which astronomers now recognise as a Cepheid variable , these are stars that astronomers use to work out the distance to other galaxies. The prototype Cepheid, is delta Cepheus which was discovered, yes you guessed it by John Goodricke .
A few hundred yards away from Edward Piggot in York John Goodricke had just discovered the variability of beta Lyra which would become the prototype of this class of stars. This is a system of 2 stars that are so close together that the gravitational pull of the stars pull them out of shape from a spherical to an ellipsoidal shape. Goodricke would be totally unaware of this.
Wednesday 9 September 2020
Donati and the Problems of Looking at Heavenly Bodies
I came across this letter and realised that problems we have today using telescopes are not new and that peoples’ perception of what someone might be looking at through a telescope haven’t changed over the centuries.
In 1870 there was an objection to the building of an observatory by Giovanni Donati of comet fame.
In a letter from La Comtesse Baldelli from Florence who was visited by Donati, the subject of conversations was the worries and obstacles he had to experience before he could place the very first stone of his new observatory. When all objections and last, not least the formalities were exhausted the inhabitants of the adjoining villas claimed an indemnity at his hands - for what do you think?
La perdita della liberta (the loss of liberty) Donati was astonished and asked in what he caused so grave an accusation?
The reply was your telescope will be pointed at our windows whenever you fancy, and the ladies will be annoyed! It took some explanation to make them comprehend that however similar to celestial bodies the ladies might be, such telescopes as used at the observatory could not be used towards objects so removed from the heavens in distance!
While some stars that make major parts of a constellation simply vary in brightness for example Algol in Perseus some just disappear for periods of time. Mira or omicron ceti is the most famous example of these stars but another Mira type star Chi Cygni in the constellation of Cygnus the swan is just fascinating.
If you can locate Deneb which is one of the three stars that make up the summer triangle of stars and draw a line down you will come across the star gamma and continuing this line you will reach beta or Albireo a splendid double star. About two thirds the distance from gamma to beta you will find chi.
Mira type variable stars are huge stars which typically if placed where the Sun is would fill the solar system out to the orbit of Mars, These are star that are dying, they will throw off their shell of gas to leave a planetary nebula, these nebula were so named because when astronomers first saw them through telescopes they looked like planets. These planetary nebula will eventually push all their gas into space leaving just a small white dwarf star. This is the ultimate fate of our own Sun.
When it comes to Miras chi Cygni is among the mote extreme examples of this class of star. When at its brightest is can be seen as a star of magnitude 3.3 making it easily visible to the naked eye. It can however fall in brightness down to magnitude 14.2 which is around 15,000 times fainter than when at its brightest. This period for light changes takes 408 days much longer than the usual 300 or so days for most Mira to take. Mira Ceti itself takes 331 days. Chi lies at a distance of about 590 light years,
But these statistics are not what make Chi Cygni special, it happens to be one of the coolest red giants with temperatures ranging from 2,200 degrees and 2,500 degrees. It is part of a rare group of stars that have a spectral class of S. Chi itself is a S6 class star.
Tuesday 8 September 2020
A Cooke and a Transit in Mauritius
The transit of Mercury was observed on November 14th 1907 from the Royal Alfred Observatory in Mauritius using a Cooke 6inch refractor. The transit which was seen through a cloudy sky and the limb of the Sun was described as being boiling. Mercury appeared as a clear cut black disc, perfectly circular with no spot or fringe.
There were 11 photographs taken during the transit with the 6 inch Cooke which had been supplied to Mauritius by the colonial government in1874 in order to observe the transit of Venus.
Monday 7 September 2020
The Astronomy Show 7th September 2020 7.00 pm - 9.00 pm
On the Astronomy Show tonight I will be looking at what can be seen in the sky during the next seven evenings. There will be the latest astronomy news, I will be looking at the types of stars in the sky. I will continue with the A-Z of Constellations and the Messier Marathon plus the astronomical anniversaries for this week.
The Astronomy Show 105.3FM only on Drystone Radio can be heard live on line at www.drystoneradio.com if you cannot listen live then the show can be heard on the Drystone Radio podcast for the next 30 days.
Alpha Gemini, Castor which means the ‘Horseman’ is one of the twin sons of Zeus and Leda in Greek mythology, the other is Pollux and the pair form a prominent pair just over 4 degrees apart, Castor is slightly fainter than Pollux.
In classical Greek Castor and Pollux were often identified with St Elmo’s fire which can be seen in the riggings of ships, it is electrical discharges during storms. It was always seen by sailors as omens of good luck helping the mariners to safely reach port.
Castor can be seen as a star of magnitude 1.9 and is 51 light years away, and it is an A3 class star hotter than the Sun. Castor appears to the naked eye as a single star bit in fact it is a star system made up of no less than 6 stars.
Castor was probably seen as a double star as early as 1678 by Cassini there is also a faint red dwarf star which is part of the system it is a variable star with the designation of YY Gemini. And just to complicate the situation even further each of these three stars is a double itself which explains why there are 6 stars in the Castor star system
Comet Borelly and Isaac Roberts
Discovered on the 21st July 1903 by M Borelly at the Marseilles Observatory the comet would become an easy naked eye object at magnitude 2.5 it was observed until August 24th when it became to close to the Sun to be seen.
Isaac Roberts at Crowborough, photographed the comet the top and bottom photographs of the comet were taken using his 5 inch Cooke telescope while the middle one was taken with his 20 inch reflector.
During the time the comet was in the sky the weather was poor and when the weather was clear the Moon was near full making photography difficult. That sounds a bit like the weather today!
Sunday 6 September 2020
Comet Perrine and The Isaac Roberts Cooke Telescope
On August 31st 1902 Charles Perrine at the Lick Observatory in America discovered a comet, this was Comet b 1902 Perrine. It was discovered in the constellation of Perseus.
The comet was photographed by Isaac Roberts using his 5 inch Cooke telescope. Roberts made a series of 5 photographs of the comet between September 6th and October 10th. This is an example of one of those photographs.
He also photographed comet Perrine 6 times using his 20 inch reflector.
Isaac Roberts began his astronomical career in 1878 at Rock Ferry on the Wirral Peninsular using a 7 inch Cooke telescope, in 1882 he moved to Maghul near Liverpool and in 1890 he moved to Crowborough in East Sussex where he observed comet Perrine.
Capella is the most northerly of the first magnitude stars. In brightness it is virtually equal in brightness to Vega which occupies the overhead point in summer a position that is occupied by Capella in winter.
Capella or alpha Aurigae is the brightest star in the constellation of Auriga the Charioteer, it is also the 6th brightest star in the sky. In mythology Auriga is said to represent Erechthonius, son of Vulcan, the blacksmith of the gods who invented the four horse chariot.
Capella means the ‘She-Goat’ and just below Capella is a triangle of three stars called the kids a very prominent feature of the winter skies and a sure sign that the star you think you are looking at really is Capella.
Capella is a G3 yellow giant star lying at a distance of 43 light years. In 1899 astronomers discovered that Capella is a double star , the second star referred to as Capella b is also a yellow giant star. The two stars orbit each other every 104 days. There is also a pair of red dwarfs that orbit at a distance of around about 1 light year.
Over the years it was thought that there were five other stars in the Capella system, however astronomers have now discovered that these stars are merely line of sight stars and are not connected with Capella.
Capella also appears to be one of the brightest sources of X Rays in the sky, this is thought to come from Capella a.
Thomas Cooke and the BBC TV Antiques Road Trip
Yesterday I participated in filming an episode of the BBC TV Antiques Road Trip as a guest 'expert' talking about the instrument maker Thomas Cooke of York.
There was four hours of filming for about four minutes of TV!! As far as I am aware it is due to be aired sometime next year. It was great fun but quite tiring.
filming was undertaken at the York Castle Museum in their Victorian
Street where there is a ‘T. Cooke & Sons’ shop front. We also
filmed at the York Observatory in the Museum Gardens where there is a
4.5 inch Cooke telescope.
Friday 4 September 2020
Eton School Observatory and Thomas Cooke
In 1870 one of the masters possible H G Madan at Eton School decided that they would provide a telescope. They chose a 5.9 in Thomas Cooke & Sons Refractor. The observatory was also made by Cookes. The observatory was erected on the roof of the western tower of the New Schools. It is square and surmounted by a revolving dome.
Although a telescope on a roof will never be completely free from vibration it is reduced to a minimum by supporting the telescope on two massive trussed iron girders stretching across the observatory. The floor is supported quite independently.
The telescope which was up the normal Cooke standards was supplied with the new Cooke clockwork driving system which was designed by the late Thomas Cooke.
The science master at Eton School was H G Madan who was the brother of Falconer Madan who was himself the grandfather of Venetia Burney who suggested the name Pluto for that newly discovered planet.
I believe that the Eton telescope is still in use today in a different observatory located next to Eton Golf Course and is used by the Herschel Astronomical Society.
One of the loveliest stars in the sky which sadly cannot be seen from Britain. It is the second brightest star in the sky after Sirius. It is also a rather strange fact that the three brightest stars in the sky Sirius, Canopus and Alpha Centauri are all in the southern sky while the next three brightest ones Arcturus, Vega and Capella are in the North.
The fact that it could be seen from Alexandria but not Athens was one of the arguments put forward by Greek astronomers that the Earth must be round.
Canopus or alpha Carinae is the brightest star in the constellation of Carina the Keel. Canopus traditionally marked the rudder of the ship, which used to be part of the massive constellation of Argo Navis the ship that Jason used to look for the Golden Fleece. The constellation of Argo has now been broken up into four smaller groups.
The legendary Canopus was a character in the saga of the Trojan war, he was the pilot of the ship which carried King Menelaus home after the fall of Troy.
Canopus lies at a distance of 310 light years and is an A9 giant star with a surface temperature of around 7,300 degrees.
Canopus is used as a star tracker for space craft and was used in 1964 by Mariner 4 which was the first space craft to successfully fly by the planet Mars. Incidentally it also changed scientists’ views of what Mars might look like from close up.
Thursday 3 September 2020
One of the most famous and most interesting stars in the sky. It is ranked as the 10th brightest star in the sky, but although being labelled as alpha it is usually slightly below beta or Rigel in brightness. It is a variable star normally varying between 0.3 to 0.8, its a semi regular variable star with a variable period of between 400- 1,000 days. However during during 2019 and 2020 it became much fainter than normal and caused astronomers many headaches.
Betelgeux which is sometimes pronounced as quite unofficially as Beetlejuice, its name is Arabic and means the ‘Shoulder of the Central One’ and is a red supergiant star. In fact it is so big that if it was placed where our Sun is all the planets out to Jupiter would be inside the star, Betelgeux lies at a distance of about 700 light years. As it is very large and close to us astronomers can actually see a disk rather than just a dot. It is one of the largest stars that can be seen with the naked eye.
Betlegeux will become a supernova within the next million years which astronomically speaking is a very short period of time and as I mentioned earlier in 2019/20 it became very faint and fell to magnitude 1.7 well outside its usual range, and many astronomers believed it is was to go into its supernova phase and blow up and destroy itself. It took some expert astronomers some time to consult historical records which showed that this had it had faded in brightness back in 1927 and 1941.
Astronomers now think they understand what caused Betelgeux to become more fainter than normal, using the Hubble Space Telescope they saw a large amount of dense hot gas moving out from the star. This gas then may have cooled down and formed a dust cloud that partially blocked the light from Betelgeux reaching the Earth.
Betelgeux will become a supernova at some point in the future and you can be quite sure that astronomers with regards to what has just happened will be paying even more attention to this old red supergiant than they would normally do.
Wednesday 2 September 2020
Can too many Cookes ruin a Transit?
Well they can if the weather is poor.
The transit of Mercury on May 6th 1878 was observed by many astronomers including Mr John Brett and Mr Walter Pye. Brett was using a 4 inch Cooke and Pye a 3 inch Cooke. The observations were made from Mr Brett’s observatory in Putney, near London.
Both first and last contacts were missed by impenetrable mist, it was then seen through a fine film of cloud. When Mercury could be seen as a black dot it was surrounded by a ring of bright light.
The clouds made observations difficult but whenever they were able to see Mercury it was surrounded by this ring. Due to the very large amount of cloud and observing conditions Mr Pye could only use a power of x50 on the 3 inch Cooke while Mr Brett using the 4 inch Cooke had to use rather less magnifying power on the 4 inch Cooke.