The Full Thunder Moon in July

 The full moon on July 10th  is known as the Thunder Moon as this is the month of the year when we are most likely to get thunderstorms

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Cooke Telescope Tales 1 - Thomas Cooke & Sons telescope for sale in India in 1891

 Civil and Military Gazette (Lahore) Saturday 3^rd January 1891

 

For Sale, owner leaving India 

An equatorial telescope of 6 inches aperture by T Cooke & Sons, York, driven by clockwork, with stellar and solar prisms and a lot of eyepieces. 

Also the revolving roof or dome (16 feet in diameter) of sheet zinc on teak frame, covering the telescope. 

H B Hederstedt 

late chief engineer of the Oude and Rohilkund Railway, Lucknow

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A little ramble through Cepheus the King

 It has often been said that “The female of the species is more deadly than the male”. In the case of this constellation 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. However the constellation 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.

Cepheus is a circumpolar constellation as seen from Britain which means it can be seen all year round.

Cepheus seems to have attracted interest almost from the beginning of recorded history. It relates to the story of Jason and the Argonauts. Cepheus is married to Queen Cassiopeia who’s the person who manages to upset the water nymphs and Neptune who was god of the sea then sends a sea monster the Cetus to attack her land.

To only way to save their land is to have their daughter Andromeda chained to a rock waiting for the sea monster to attack her, but at the very last minute our hero Perseus riding the winged horse Pegasus arrives on the scene. He has just killed the Medusa a creature with her hair made of snakes and just to glance at her one would be turned to stone. Perseus rescues Andromeda, hey are married and live happily ever after. All the characters including Cephus can be seen in the sky. If you have ever seen the film, the Clash of the Titans can see the story.

Most ancient civilization seemed to refer to Cepheus by that name, the Persian astronomers had several variations to that name the main one would be Phicarus or the Fire Kindler. The Hindus knew Cepheus as Kapi the Ape god. The Chinese believed that within the constellation was the Inner Throne of the Five Emperors.

The Arabic astronomer Al Ferghani called the constellation Al Radif the Follower. This may have come from some misunderstanding from the nearby Al Ridf in the tail of Cygnus the Swan, for the name Cepheus does not seem to ever to have been known by any such title in Arabic astronomy.

The brightest star in Cepheus is alpha or Alderamin which originally meant the right arm but today is the right shoulder. The star has a brightness of magnitude 2.5 it’s an A class star meaning it’s hotter than our Sun. It also is close to us being only 49 light years away. In around the year 7,500 it will become the North Star. This is due to a process called precession or the wobbling on the Earth on its axis.

Beta or Alfirk which to the Arabic astronomers means the Flock is a B class star with a surface temperature of around 23,600 degrees much hotter than our Sun which has a surface temperature of around 5,800 degrees. Alfirk is around 690 light years away and has a magnitude which varies very slightly from 3.1 to 3.3.

To the Arab astronomer’s gamma or Arrai means the Sheppard. While the Chinese astronomers called the star Shaou Wei or the Minor Guard. With a magnitude of 3.2 it’s a K class giant star cooler the Sun and can be found 45 light years away.

Delta, which has no name is the famous variable star discovered by the deaf astronomer 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 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.

The importance of this discovery to astronomers was of course unknown to Goodricke but cepheid type variables are of immense importance to astronomers today trying to work out how far away galaxies and clusters are.

This would be John Goodricke’s last astronomical discovery of his very short life at the age of just 22.

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, it varies from a F supergiant to a G supergiant class star, with a surface temperature  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.

The only star cluster I will mention is NGC 188 it cannot be seen with the naked eye as its brightness is only magnitude 10, meaning a small telescope would be needed to see it. NGC 188 is an open cluster and was discovered in 1825 by John Herschel who was the son of William Herschel who had discovered the planet Uranus in 1781.

Open clusters are much younger clusters than globular clusters.  The stars of open clusters usually drift apart after a few million years. However, because NGC188 lies far above the plane of the Milky Way Galaxy where there is far less gravitational interaction with the Milky Way the cluster has stayed together.

 It appears to be one of the oldest open clusters being about 6.8 billion years old. It lies at a distance of around 5,000 light years and is one of the closest clusters located near the Pole Star.

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Thomas Cooke & Sons telescope sent to Calcutta in 1903

 In 1903 Thomas Cooke & Sons of York supplied a 4.5 inch telescope to the Government Observatory in Calcutta, India. The head of the observatory was Mr Evershed, Attached to the telescope was a 5 inch Camera also supplied by Cookes.

The telescope was mounted on a Cooke iron pillar which were housed in a shed. This shed was mounted on wheels and rails that allowed it to be moved when the telescope was to be used.

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New Catalogue of Nebulae introduced in 1864

 New Catalogue of Nebulae 

By the English Churchman

Another splendid monument of Herschelian genius was laid before the Royal Society in January 1864, a gigantic catalogue of all the known nebulae compiled from every imaginable source.

No less than 5,063 objects are here set down, of which 2,307 are from Sir John Herschel’s own catalogue of 1833, 1,713 from his Cape observations and the residue from miscellaneous sources. The year 1860 has been adopted as the epoch for which all the mean places are computed, and not the least important feature is the systemised plan which has been adopted for describing the sizes of the various objects based on direct actual measurement.

This catalogue which will add one more to the many laurels already borne buy its distinguished author, will no doubt, be placed in the printer’s hands with as little delay as possible, but the expense of printing will be very considerable.

 

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Occultation by Jupiter observed from Canada in 1896 with Cooke telescopes

 Attempts were made on May 22^nd 1896 at several points across Canada to observe the occultation of  a 9^th magnitude star in Cancer by Jupiter. 

At the Toronto Observatory Mr F L Blake using the Cooke 6 inch refractor found the planet was too low in the sky for first class seeing, although the night was clear. 

Dr J C Donaldson of Fergus Ontario using a 3.25 inch Cooke & Sons refractor obtained a glimpse of the star, but the nearness to the horizon made observing very difficult. 

It is not known if any other observers further to the west observed the occultation.

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A little ramble through 19th century astronomy - The height of aurora

I saw the aurora of September 3^rd 1870 described by H C Key and I observed it from 10.00 to 11.00 PM but here it never reached quite to the zenith, and at 11.20 was no where high. Its brightest feature was then a distinct arch, the apex of whose central line was 12 degrees in altitude. If Mr Key’s description of the clear space of 7 or 8 degrees below the aurora in the S S E, applies to that time, it would seem that part of the aurora bordering the clear space cannot have been more than 25 miles above the Earth, and was more likely only 17 or 18 miles.

It would be well if the heights of the aurora were better known than they are; and I think if systematic observations were made simultaneously at different stations, pir knowledge of the subject would be largely increased. I am willing to be one of the observers is such an investigation, and Mr G J Symons the editor of the Meteorological Magazine , has expressed his readiness to aid.

T W Backhouse, Sunderland July 22^nd 1871

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