[Snafu]

I have a question. When did telescopes first appear in China? Did the Chinese develop their own telescopes or was it a technology that they got from contact with other cultures?

[General_Zhaoyun]

If I'm not wrong, the first "modern style" observatory in China was Yushan observatory 佘山天文台 (near Shanghai) and it was built by the french missionary in 1899. It contains China's first astronomy telescope.

The world's first telescope was invented by Galileo.

[Liang Jieming]

Not true. Song dynasty troops were using telescopes to spot their artillery.

[Alexander39]

Liang Jieming, on Aug 23 2005, 08:24 AM, said:

Not true.  Song dynasty troops were using telescopes to spot their artillery.

More probably a *seeing glass* a very primitive and elementary form of a telescope, used long before the Song by the way, the problem whit constructing a proper telescope is that you have to shape the glass in a perfect conclave shape before it is used, it is far from as simple as it sounds.


Phoenicians cooking on sand discovered glass around 3500 BCE, this is probably a *urban legend* serious historians is convinced that it was Egyptians that inventet the process and used it commercially first, but that the Phoenicians took and refined the process and spread it around, but it took about 5,000 years more for glass to be shaped into a lens for the first telescope. A spectacle maker probably assembled the first telescope. Hans Lippershey (c1570-c1619) of Holland is often credited with the invention, but he almost certainly was not the first to make one. Lippershey was, however, the first to make the new device widely known.
The telescope was introduced to astronomy in 1609 by the Italian scientist Galileo Galilei, who became the first man to see the craters of the moon, and who went on to discover sunspots, the four large moons of Jupiter, and the rings of Saturn. Galileo's telescope was similar to a pair of opera glasses in that it used an arrangement of glass lenses to magnify objects. This arrangement provided limited magnification--up to 30 times for Galileo--and a narrow field of view; Galileo could see no more than a quarter of the moon's face without repositioning his telescope.

In 1704, Sir Issac Newton announced a new concept in telescope design whereby instead of glass lenses, a curved mirror was used to gather in light and reflect it back to a point of focus. This reflecting mirror acts like a light-collecting bucket: the bigger the bucket, the more light it can collect. The reflector telescope that Newton designed opened the door to magnifying objects millions of times--far beyond what could ever be obtained with a lens.

Newton's fundamental principle of using a single curved mirror to gather in light remained the same. The major change that took place was the growth in the size of the reflecting mirror, from the 6-inch mirror used by Newton to the 6-meter (236 inches in diameter) mirror of the Special Astrophysical Observatory in Russia, which opened in 1974.

The idea of a segmented mirror dated back to the 19th century, but experiments with it had been few and small, and many astronomers doubted its viability. It remained for the Keck Telescope to push the technology forward and bring into reality this innovative design.

A binocular is a optical instrument for providing a magnified view of distant objects, consisting of two similar telescopes, one for each eye, mounted on a single frame. The first binocular telescope was invented by J. P. Lemiere in 1825.

The Early History of the Binocular
The modern prism binocular began with Ignatio Porro's 1854 Italian patent for a prism erecting system.

The First 300 Years of Binocular Telescopes
"What we call a binocular is a binocular telescope, two small prismatic telescopes joined together. When Hans Lippershey applied for a patent on his instrument in 1608, the bureaucracy in charge, who had never before seen a telescope, asked him to build a binocular version of it, with quartz optics, which he is reported to have completed in December 1608."

Telescopes and their Makers
"Box-shaped binocular terrestrial telescopes were produced in the second half of the 17th century and the first half of the 18th century by Cherubin d’Orleans, by Pattroni in Milan, and by I.M. Dobler in Berlin; but were not successful because of their clumsy handling and poor quality."

Telescope Facts - James Short
The Short Telescope, was made by the Scottish Instrument maker James Short in 1740. An optician and astronomer, James Short invented the first perfect parabolic and elliptic, distortionless mirror ideal for reflecting telescopes. James Short built over 1,360 telescopes.
From 'James Short a Biography'

This post has been edited by Alexander39: 23 August 2005 - 01:52 AM

[Snafu]

Liang Jieming, on Aug 23 2005, 06:24 AM, said:

Not true.  Song dynasty troops were using telescopes to spot their artillery.

Are there any images of these Song telescopes? I'd be curious to see what they looked like.

[somechineseperson]

General_Zhaoyun, on Aug 23 2005, 06:17 AM, said:

If I'm not wrong, the first "modern style" observatory in China was Yushan observatory 佘山天文台 (near Shanghai) and it was built by the french missionary in 1899. It contains China's first astronomy telescope.

The world's first telescope was invented by Galileo.

Wasn't the first telescope in China brought to China by the Jesuits in the late Ming Dynasty?

[historylover]

Can you describe this "Seeing Glass" and how it was constructed possibly by the Song? I'm interested in how it gathered light and how it magnified.

Just to add what was already stated:
Galileo's telescope was quite primitive. It used a single convex lens as the objective and a single concave lens as the eyepiece. With these two lenses this gave a 'right-side' or 'erect' image. It's hard to get more simple than this. So I'm curious what these Seeing Glass instruments really were.

Newton's reflecting telescope used a concave parabola mirror for the objective. This performs the same function as an object glass (lens). They both gather light. The advantages of mirrors over lenses as objectives (light gathering components) in sizes greater than a meter are 1) len glass must be highly transparent and homogeneous - mirror glass does not. Light does not go through mirrors. 2) Lenses have to be held in place at the edges, mirrors have full support in the back. In large sizes, lens tend to sag, so they must be very thick. The 40 inch telescope at Yerkes is about a foot thick. 3) Chromatic aberration is non-existent with reflecting telescopes. It's a significant problem, especially with large refractors.

A side note: Magnification is not nearly as important as light gathering power.

This post has been edited by historylover: 04 November 2005 - 09:32 PM