Tuesday, 8 July 2025

A little ramble through 19th century astronomy - Mr Rutherford of New York and photographs of the Moon in 1871

 From Nature Magazine November 9th 1871

Mr Rutherford of New York, the most eminent American amateur astronomer, and especially known for his magnificent photographs of celestial bodies, has lately presented to Mr Brothers of Manchester an English astronomical photographer, three superb negatives of the moon- one representing her in the first quarter, one when full and one in the third quarter; and it is proposed to publish these in a volume containing about one hundred pages of descriptive letterpress.

The work will also contain a map of the Moon, as we see her, and a chart, on the stereographic projection, showing the true shape and the relative dimensions of all the chief lunar features. The letterpress, map and stereographic chart will be prepared by Mr Proctor; the photographs by Mr Brothers. The work will be got out on a magnificent scale, and sold at a guinea and a half.


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Monday, 7 July 2025

Cooke Telescope Tales 2 - Kodaikanal Observatory, India 1908

 

On February 18th 1908 Mr Evershed at the Solar Physics Observatory, Kodaikanal, South India using a 6 inch Thomas Cooke & Sons telescope took a  series of photographs of a solar prominence. The remarkable appearance of this kind of prominence has seldom been recorded.  20 photographs were taken with 14 being reproduced here.

 

Visual observations were also made which indicated  a moderately bright mass of prominences


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The Astronomy Show on Drystone Radio

 Join me, Martin Lunn MBE every Monday evening from 7.00 pm-9.00 pm on the award-winning Astronomy Show on Drystone Radio, probably the only regular astronomy show on any radio station in the country. 

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 latest news from the astronomical societies in the north of England. 


The Astronomy Show every Monday evening only on Drystone Radio live online at www.drystoneradio.com DAB radio in Bradford and East Lancashire, or 102 and 103.5 FM and can also be heard later on the Drystone Radio Podcast.


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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Sunday, 6 July 2025

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

 Civil and Military Gazette (Lahore) Saturday 3rd 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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Saturday, 5 July 2025

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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Friday, 4 July 2025

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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