Galileo gets clouded out!

So having spied three starlets close to Jupiter, Galileo was anxious totake another peek on this date, 9 January, exactly 400 years ago today. But he was disappointed --clouded out. It happens to us all. I have been clouded out at three total solar eclipses. Stay tuned for tomorrow-- the starlets are playing hide and seek

Links: follow the links in yesterday's blog

Galileo asks: did Jupiter move east last night?

On 8 January 1610 Fate compelled Galileo to take his second look at Jupiter. This time all three little stars were west of Jupiter, whereas the night before two of them were east of Jupiter. That riased a huge question in his mind: Had Jupiter moved eastwards since the 7 January? Such a proper motion would be entirely at odds with the computations of astronomers.

My source is a new translation of Sidereus Nuncius http://bit.ly/7WsibK

Media followers, editors, etc can find me at http://bit.ly/TOTast

Galileo: 400th anniversary Moons of Jupiter

Exactly four hundred years ago today (ignoring the effect of calendar reform) Galileo first spied three stars close to Jupiter: two to the east and one to the west. On his first sighting he could not, of course, note anything unusual (his telescope could see millions of stars), but they caused him surprise because they were in a straight line parallel to the ecliptic.

Come back tomorrow to see what happened next!

Links and acknowledgement can be found on blogs below

Galileo: seeing stars to magnitude 12

In Sidereus Nuncius (1610), Galileo writes that his telescope allows him to see a further six orders of magnitude. The Greek astronomer Hipparchus devised the magnitude system in about 150 BC. The brightest stars were first nagnitude and the faintest visible to the naked eye sixth magnitude. A first magnitude star emits 100 times the light of a sixth magnitude star. Ptolemy uses this convention in the Almagest.

Galileo's telescope showed stars frommag 7 to mag 12. The light from a mag 12 stars is 10,000 times fainter than mag 1. Galileo described the 7 - 12 mag stars as "so numerous they are almost beyond belief.

Source of this information: follow the links in yesterday's blog

Galileo gets a pay rise

On 24 August 1609, just over 400 years ago, Galileo visited the Ducal Palace in Venice to present a spyglass (telescope) to the Doge. At this date Galileo has yet to turn his telescope to the heavens. His accompanying letter assigned the copyright to the Venetian Republic. He explained that the spyglass could be used tosee approaching enemy boats at muchgreater distance thanbyeye alone, allowing more time "for engagement, pursuit or flight".

The chairmanship of the Venetian Senate rotated weekly. One of Galileo's chums had the chair that week. In 1608 he had the University of Padua increase Galileo's salary from 160 florins to 320 florins a year payable in advance. On 25 August this influential supporter, Antonio Priuli, had the Senate grant Galileo tenure for life, and an increase in salary from 320 florins to 1000 florins, the highest salary the university ever paid to a professor of mathematics

My source of this information http://bit.ly/7WsibK

Media followers who would like help to cover Galileo's discoveries of 1610 can contact me via http://bit.ly/TOTast

Galileo resolves misty nebulae into stars 1610

In his stunning book A Sidereal Message (actual title is Sidereus Nuncius, normally translated incorrectly as The Starry Messenger)Galileo lists eight telescopic discoveries,anyone of whichwould have earned the Nobel Prize established some 300 years later!

Philosophers had long puzzled over structures in the universe that had the title 'nebulous stars' by the early seventeenth century. The word nebulous does not mean insterstellar matter (that use had to wait for William Herschel), but meant cloud like. Claudius Ptolemy, in the Almagest lists seven of these, which Galileo examined using a 20X power Galilean telescope.

He resolved them in numerous faint stars. In the head of Orion he found 27 stars, and in Praesepe 40 stars

My source of this information http://bit.ly/7WsibK

Media followers who would like to cover Galileo's discoveries of 1610 cancontact me via http://bit.ly/TOTast

Galileo and the Moon Sidereus Nuncius

Here's what Galileo wrote 400 years ago this month to describe the Moon:

He used a telescope that magnified 20 times

"The observational evidence is so compelling that anyone can grasp for himself that the moon's surface is not smooth and polished but rough and uneven. Like the Earth it is covered all over with huge bumps, deep holes, and chasms" He went on to provide sketches of the terminator, showing large craters and high mountains.

Five years later, on 28 February 1615 he received a sharp letter from a high officer of the Vatican warning of the dangerous speculation arising from his claims, namely that the Moon had similarities to Earth.

My source of this information http://bit.ly/7WsibK