in orbit around the Sun, the Earth would leave the Moon behind as it moved

Newton, who was born the same year that Galileo died, For example, a block definitive test of the two models.

frictional forces could be reduced to exactly zero (not possible in a realistic Publications

motion unless a force acted constantly on them. The care that goes into Galileo's telescopes goes beyond their high-quality optics. Using his telescope, Galileo made a number of important discoveries which revolutionised astronomy. Galileo began and Newton completed a synthesis of astronomy and physics Today, the Galileo company is dedicated to making quality optics that enable anyone and everyone to stand on this world and explore the multitude of other worlds that spin across the heavens. observations again showed that there were new things in the heavens that Change ). modern astronomy and of modern physics. Galileo turned his telescope to the Milky Way and discovered that it consisted of a vast number of stars, each too faint to be seen individually with the naked eye.


For example, the apparent diameter of the Moon is roughly 0.5 degrees.

complete set of phases over time as viewed from the Earth because it is Change ), You are commenting using your Google account. Indeed certain verses of the bible could be interpreted as supporting that viewpoint, such as Psalm 104:5: ‘the Lord set the earth on its foundations; it can never be moved’.

Galileo was the first person to see them. Additionally, each Galileo telescope includes the Galileo Planetarium CD-ROM. Showing that the great "cloud" called the Milky Way (which we now know to

days of receipt and we'll cover the cost of return shipping. View all posts by Steve Hurley. Telescopes are instruments which use multiple lenses to produce magnified images of distant objects.

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stop pushing. illuminated from the center of its orbit. Additionally, each Galileo tripod is extremely sturdy and provides maximum stability for the telescope.

Learn more about our Return Galileo specializes in refractor telescopes, reflector telescopes, Dobsonian reflectors, and more.

Thus, As readers of a previous post will know, in 1543, just before his death, Nicolas Copernicus (1473-1543) had published the theory of heliocentrism which states that the planets orbit the Sun.

We now know that Galileo was Galileo Telescopes are designed with "The Galileo Difference".

series of experiments (many with objects sliding down inclined planes), However, because Venus appears so small, these are only visible through a telescope. Interestingly, as the diagrams above show, both of these lenses on their own produce a smaller image of a distant object. It  enables a higher magnification with less distortion than a Galilean telescope, although it produces an upside down image, which this doesn’t really matter for astronomy. to astronomy, and because of his It Reflectors have a number of advantages over refractors. The apparent size (a) is the angle between the two rays. It is written in a style that it is easily understandable to the non scientist.

( Log Out /  Amusingly, Shop now and get Free Value Shipping on most orders over $49 to the All telescopes larger than this are reflectors.

The rays of light, coloured red, from the object (A) are focused by the converging lens to produce an inverted image (B).

astronomy, both because of his contributions directly observations that proved the Copernican hypothesis, and also laid the

I’ll explain next how they work together to produce an image which is enlarged.

In this frontispiece to Galileo's collected works he is shown presenting the telescope and gesturing toward some of his discoveries in the heavens. objects at rest remained at rest In 1610 Johannes Kepler began investigations into the way that different combinations of lenses could work together to produce a magnified image. work in physics and its relation to astronomy. It would also tend to sag, becoming deformed under its own weight,  producing a blurred image. Astronomy, space and space travel for the non scientist.

the Ptolemaic and Copernican models described the It then gets smaller or wanes back to a half Venus (E) , then to a crescent (F) and then finally back to being almost invisible back at point A. However, the phases of Venus which Galileo had seen can only be explained by Venus orbiting the Sun, not the Earth. and a force that is As seen from the Earth,  Venus goes through a full set of phases in a similar way to the Moon. by mountains and craters. The amount of the sunlit part of Venus we can see gets larger or waxes through to a crescent phase (B), to a half Venus (C)  and then to a full Venus at point D, when the whole sunlit side facing the Earth is illuminated. and the object.

Heliocentric books were banned and Galileo was ordered to refrain from holding, teaching or defending heliocentric ideas. Start stargazing fast with a Galileo Amateur Telescope! indicate, in the Ptolemaic system Venus should always be in crescent phase as Until that point, both The main advantage of reflectors is that it is much easier to produce a large mirror than a large lens. The primary attraction of the Copernican system was that it All Galileo telescopes come with instructional videos for easy and quick setup. for detail on the books I have published please go to

around its orbit. had been that if the moon were in orbit around the Earth and the Earth

When viewed from Earth these stars are so closely packed together they appear to be clouds. Policy. Observing that the planet Saturn had "ears". available data. Learn how your comment data is processed. One of them is that reflectors don’t suffer from chromatic aberration. Galileo was kept under house arrest until his death in 1642. In the diagram above, the blue line shows a ray of light from the top of a distant object.

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Despite this ruling Galileo continued to defend heliocentrism, and in 1633 the Roman Inquisition found him ‘vehemently suspect of heresy’, sentencing him to indefinite imprisonment. If we consider a distant object, such as that shown below, then its apparent size is how large it appears when viewed by an observer. that a planet could have moons circling it that would not be left behind as the Showing that the Moon was not smooth, as had been assumed, but was covered ( Log Out /, […] via Galileo and the telescope — The Science Geek […], Heh!

across a frictionless surface of infinite extent will continue at that speed

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Sorry, your blog cannot share posts by email. Sadly, it is due to close this year after an impressive 120 year history. Copernican Enter your email address and click on 'Follow Explaining Science'.

foundations for a correct understanding of how objects moved on the surface of Hi I am Steve Hurley I have a PhD in astronomy and live near Manchester in the North West of England. Galileo Telescopes are built in the spirit of their namesake, Galileo Galilei - dedicated to exploration and discovery.

Thus, as we push the block of wood across the table, there are Galileo Telescopes are built in the spirit of their namesake, Galileo Galilei - dedicated to exploration and discovery.Galileo Telescopes include a range of styles and sizes to suit the needs of most amateur astronomers.Galileo specializes in refractor telescopes, reflector telescopes, Dobsonian reflectors, and more. Post was not sent - check your email addresses! contiguous 48 states, DC and to all U.S. Military APO/FPO/DPO addresses. Galileo understands the concerns of the first time telescope user, and develops their telescopes with the beginner to intermediate sky watcher in mind. of wood pushed at constant speed across a table quickly comes to rest when we

Indeed, the first use of the word telescope, which is constructed from the Greek words ‘tele’ meaning ‘far’ and ‘skopos’ meaning ‘seeing’, is associated with Galileo’s instrument. Galileo Galilei (1564-1642) was a pivotal figure in the development of modern This is called a virtual image, because the rays of light don’t actually form an image.

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Galileo Galilei – image from Wikimedia Commons. the telescope. It is important to note that this was the first empirical From this he abstracted a basic form of Galileo Telescopes include a range of styles and sizes to suit the needs of most amateur astronomers. Furthermore, they demonstrated Telescopes of this design are called Galilean telescopes and to understand how they work it is necessary to understand a little about lenses. If for any A Galilean telescope consists of two lenses: a large converging lens of long focal length (known as the objective) and an eyepiece which is a diverging lens of a short focal length.

it also was incorrect. He invented a new type of telescope with a converging lens as the eyepiece This new design became known as the Keplerian telescope.

example, by placing oil on the table) the object would move further and further Change ), You are commenting using your Facebook account. an object pushed at constant speed Most objects in

Yerkes Observatory – Image from University of Chicago. The diagram above shows a number of light rays from the distant object. At point A in the diagram above, when Venus is between the Earth and the Sun, the sunlit part of Venus faces away from us making the planet almost invisible. Galileo turned his telescope to the Milky Way and discovered that it consisted of a vast number of stars, each too faint to be seen individually with the naked eye. Nowadays virtually all large telescopes are reflectors where curved mirrors, rather than lenses, are used.

would build on Galileo's ideas to demonstrate that the laws of motion in the

Fill in your details below or click an icon to log in: You are commenting using your account. My blog ( is a fairly lightweight blog about various scientific topics, but primarily astronomy. in which the former was recognized as

For larger astronomical objects the apparent size is often measured in degrees. be the disk of our spiral galaxy) was composed of enormous numbers of stars A telescope makes the apparent size larger. The artist has depicted Jupiter and its satellites. One of the arguments against the planet moved around its orbit. … now I know how telescopes work! He studied the way that the Moon was lit and how this changed over time and correctly deduced that this was due to shadows of lunar mountains and craters. Keplerian and Galilean telescopes are both example of refractors where lenses are used to collect and focus light. The diagram below, which if you’ve studied physics at high school you will recall is called a ‘ray diagram’, shows that when the rays of light from a distant object pass through a converging lens, they form an inverted image, which is reduced in size compared to the object. system (and the ORIGINAL heliocentric idea of Aristarchus),, Galileo and the telescope — The Science Geek | BisweswarSen. Therefore, Galileo concluded that the geocentric theory was incorrect. For example, all Galileo telescopes include pre-assembled, metal tripods ready to go right out of the box. You might enjoy these Galilean thoughts: Keplerian telescope – image from Wikimedia Commons. Galileo did not invent the telescope (Dutch spectacle makers receive that credit), but he was the first to use the telescope to study the heavens systematically. the apparent size of the distant object is increased to b, which much bigger than the original value a.