Showing posts with label ABC Wednesday O. Show all posts
Showing posts with label ABC Wednesday O. Show all posts

Tuesday, 27 April 2010

ABC Wednesday O is for Orrery


This orrery was made in London in 1767 by Benjamin Martin and was used to teach astronomy at Harvard University. It is on display at the Putnam Gallery in the Harvard Science Center.
Image courtesy of Wikimedia Commons
An Orrery is a mechanical model of the solar system. Notwithstanding problems of scale it can be a useful tool in teaching children the relative positions of the planets. Orreries are also very beautiful. Brian Greig, in Victoria, Australia, recreates historical orreries and other scientific instruments and accepts commissions to make bespoke models. His site can be seen here.Until the 16th century the unquestioned commonly and religiously held belief was that the earth was the centre of the universe and the sun, planets and stars revolved around it. Heaven was a fixed place and perfect. Any other opinion was considered to be heresy.
The Polish astronomer and mathematician Nicolaus Copernicus (1473 – 1543) posed the theory that the earth and other planets in the solar system orbited the sun.
Copernicus' view was promulgated by the German mathematician and astronomer Johannes Kepler (1571 – 1630)
Galileo Galilei (1564 -1642) the Italian philosopher, mathematician and astronomer, also supported the Copernican theory, but was accused of heresy by the Roman Catholic church and forbidden to advocate it. He remained under house arrest for the last ten years of his life for refusing to revoke his belief in the theory.
Orrery in the Vatican Museums
Image courtesy of Wikimedia Commons
The first model of the solar system was made about 1704 by George Graham (1674 – 1751) who was a renowned clockmaker. His tomb is in Westminster Abbey. An instrument maker called John Rowley made a copy of the model for his patron, Charles Boyle, 4th Earl of Orrery. Henceforth any such model would be known as an Orrery.However, in the first century BC Cicero claimed that the Greek philosopher Posidonius, had built an orrery showing the daily movement of the sun, moon and five known planets. It may have resembled the Antikythera mechanism.
Main fragment of Antikythera Mechanism - probably the first known orrery
Image courtesy of Wikimedia Commons
There is a Human Orrery at the Armagh Observatory in Northern Ireland.
The University of St Andrews has an Electric Orrery showing the inner and outer solar systems.Thank you to Denise Nesbitt and her merry band for their work in organising and hosting this meme. To see more Os – and perhaps join in – please click here.

Wednesday, 28 October 2009

ABC Wednesday Round 5 - O is for Ocicats

Winston and Monty as kittens, still growing into their ears
O is for Ocicats. The Ocicat is a 'man-made' breed, the result of an American breeder trying to create an Aby-pointed Siamese. She crossed an Abyssinian with a Siamese and one of the kittens was spotted, looking rather like an Ocelot. Her daughter remarked on this and so the kitten was called an Ocicat. He was never bred from - in fact he was neutered - but spotty kittens from subsequent litters were kept and bred. Outcrosses were made to American Shorthair cats to introduce the silver gene and greater body substance. Consequently there is a fairly large and diverse gene pool and Ocicats are not subject to the inherited problems of more selectively-bred cat breeds. It is permissible to breed them with Abssinians and this again increases the gene pool. Monty curls up with Frodo

Winston relaxes with Jenna

Monty with his favourite dog

Winston about to join Monty in Dominie's bed
A litter of Ocicat kittens can contain kittens of Abyssinian appearance, referred to as 'mountain lions', the expected spotted striped kittens and those with a classic tabby marking.
Ocicats are strong athletic cats and are heavier than they look.
Our two, not related, are neutered chaps. Winston is chocolate and Monty is chocolate silver.They are very dog-like in their interaction with humans and are extremely affectionate. They live very happily with our dogs and can often be found curled up with one. Monty particularly likes Jenna and frequently seeks her out.
Gillian's Foxy enjoying Monty's company. Foxy's own cat in Dorset won't tolerate such behaviour!
They don't always sleep together and sometimes squabble but usually they are the best of friends.
Thank you to Mrs Nesbitt for hosting this meme. Why not visit her here for other interpretations of the letter 'O'.