Telescopes

Telescopes, were essentially discovered in 1609. Galileo and later Keppler were the first astronomers to use them. They caught on rapidly as observing instruments and for look out purposes., it took the optician's a while to correct the inverted view on some of them, but once done, they took off.

A Barlow lens is an accessory used in telescopes to increase the focal length, resulting in magnification of the image. It allows the telescope to achieve higher magnification without needing to switch to a higher power eyepiece. By inserting the Barlow lens between the telescope and eyepiece, it effectively doubles or triples the focal length of the telescope.

Galileo is the first recorded instance of the use of a telescope, though it is well known that he developed the idea for it from a toy that arrived from a traveling merchant.

An optical telescope cannot be used during cloudy days. Of course, this assumes that the telescope is located somewhere on the Earth's surface and therefore subject to weather. Since clouds obscure the sky - and any heavenly object otherwise visible - the optical telescope will be unable to see anything. A radio telescope, however, can see through clouds, simply because clouds do not block or cause significant interference to radiowaves reaching the Earth's surface from space.

The Yerkes Telescope is the worlds largest telescope that's founded by the University of Chicago.

Reflectors - the main two types being Newtonian and Cassegrainian.

A Galilean Telescope is also an Astronomical Telescope so it is just a subset of Astronomical Telescopes.

One end of a reflecting telescope is the big hole pointed at the star. The other end of the reflecting telescope has a lens called an eyepiece.

Because the Hubble Space Telescope was designed for periodic servicing, the items to be replaced are easily accessible. Ranging in size from a shoebox to a telephone booth, most of these items can be removed or installed using special wrenches and power tools.

Through a telescope on Earth, you can see the rings of Saturn, which are the most prominent and easily observable. Depending on the telescope's size and quality, you may also discern some details of the rings, such as the Cassini Division, which is a gap between the A and B rings. Other gas giants like Jupiter and Uranus have faint rings that are much harder to see. In summary, Saturn is the only planet with rings that are clearly visible through telescopes from Earth.

Hubble

Yes, that is correct.

The primary goal of an optic is to gather light and recreate a crisp image. The reason for a large primary objective is to gather as much light as possible to see increasingly more distant objects. Crisp, highly detailed images come from what is called intferometry. This technique takes the output from multiple telescopes great distances apart and passes the data through a supercomputer that combines the image. Intferometers create what's called a "virtual telescope" whose resolution is comparable to that of a real telescope the size of the distance between the actual optics.

The Cassegrain reflector is a folded optics design, using two mirrors to fold the light path back on itself. This increases the focal length of the telescope, without increasing it's length. By doing so you can compact a more powerful telescope into a smaller frame, which has advantages for small amateur scopes (portability) and large professional ones (reduced cost).

First developed in 1672 by Laurent Cassegrain, this reflector is a combination of a primary concave mirror and a secondary convex mirror, both aligned symmetrically about the optical axis. The primary mirror usually contains a hole in the centre thus permitting the light to reach an eyepiece, a camera, or a light detector. The primary mirror is parabolic while the secondary mirror is hyperbolic.

Of the three basic types of telescopes: refractors, reflectors and catadioptrics, the Cassegrain reflector falls under the categories of reflecting and Catadioptric designs.

It was called a "Spyglass". Or, it was also called a telescope.

A telescope has a larger gathering area (the main lens, or the main mirror) than the human eye. This makes it possible to see the light of fainter objects. Another thing the telescope does is to increase angular resolution. This makes it possible, in some cases, to see two stars that are close together as two stars, whereas the human eye would see them as a single spot of light.

Our sun is the biggest object in our solar system.

Compared with some suns/stars in other solar systems, it would still be small-ish.

The "sun" or star should always be the largest object in any solarsystem.

It has got such large a mass that gravity alone is enough to "ignite" it and cause it to "burn". Not actually "burning" as in the reaction of fire as in wood and air (oxygen) but a fusion process between atoms of helium and a fission process of heavier atoms (Radioactive material) of which causes so much heat that it would appear to be intensly "burning".

It depends a bit how we define a "thing". If we concider the void between planets or the void in a solar system to be a "thing", a thing of almost nothingness, then this would be by far the biggest.

cause they gather light and concentrate it.

OH NAH! Telescopes weren't invented back in his time

The magnification of the telescope image is

(focal length of the objective) divided by (focal length of the eyepiece).

The focal length of the objective is fixed.
Decreasing the focal length of the eyepiece increases the magnification of the image.
(But it also makes the image dimmer.)

no it is not possible because it is too far away!=)

A kaleidoscope.

Galileo Galilei worked alone, which was common during his time. He did correspond with other scientists, such as Kepler.