Physics Project Report on Astronomical Telescope
A telescope is an optical instrument which is used to see the distant objects. Telescopes are of two types:
2. Galilean telescope or Terrestrial telescope
An astronomical telescope is an optical instrument which is used to see the magnified image of distant heavenly bodies like stars, planets, satellites and galaxies etc.
The final image formed by an astronomical telescope is always virtual, inverted and magnified.
Principle of Astronomical Telescope
An astronomical telescope works on the principle that when an object to be improved is placed at a significant distance from the objective lens of the telescope, a virtual, inverted and magnified image of the object is formed at the least range of distinct vision from the eye held close to the eyepiece.
Construction of Astronomical Telescope
An astronomical telescope consists of two convex lenses: an objective lens O and an eyepiece E. the focal length fo of the objective lens of a solar telescope is large as compared to the focal length few of the eyepiece. And the aperture of actual lens O is large as compared to that of eyepiece so that it can receive more light from the distant object and form a bright image of the remote object. Both the objective lens and the eyepiece are fitted at the free ends of two sliding tubes, at a suitable distance from each other.
Telescope – Introduction
In day to day life, we come across many gadgets; you might have seen some persons wearing glasses or aspects. Have you ever thought about the function of such glasses? The crystals which are mainly used for curing problems such as shortsightedness or longsighted etc. are called lenses. These lenses can also be prepared in many ways; for example, these are practiced in a telescope, microscope eye lenses, binoculars etc.
In this investigatory project, we shall discuss one of the uses of the arrangement of lenses, i.e., and we shall discuss the telescope.
The telescope is used for seeing distant objects such as stars, planets etc. Let us see their function, how they can bring a thing near to us.
An astronomical telescope is an optical instrument which is applied for observing distinct images of heavenly bodies like sources, planets etc.
It consists of two lenses, the objective lens O, which is the vast focal small aperture. The two lenses are mounted co-axially at the three ends of two tubes. The distance between these lenses can be adjusted using a rack and pinion arrangement.
In the normal adjustment of the telescope, the final image is formed at infinity. A parallel beam of light from an astronomical object is made to form on the objective lens of the telescope. It forms a real, inverted and diminished image of the object. The eyepiece is so adjusted that A’B’ lies just at the focus of the eyepiece. Therefore a final highly magnified image is formed at infinity. The final image is erect concerning A’B’ and is inverted concerning the object.
However, in an astronomical telescope, final image being inverted w.r.t. The object does not matter, as the astronomical object are usually spherical.
Magnifying Power of an astronomical telescope is a normal adjustment is defined as the ratio of the angle subtended on the eye by the final image of the angle subtended on the eye, by the object directly when the final image and the object both lie at an infinite distance from the eye.
Working of Astronomical telescope
The ray diagram to show the working of the astronomical telescope. A parallel beam of light from a heavenly body such as stars, planets or satellites falls on the objective lens of the telescope. The objective lens forms a real, inverted and diminished image A’B’ of the heavenly body. This image (A’B’) now acts as an object for the eyepiece E, whose position is adjusted so that the image lies between the focus for’ and the optical center C2 of the eyepiece. Now the eye piece forms a virtual, inverted and highly magnified image of the object at infinity. When the final image of an object is formed at infinity, the telescope is said to be in ‘normal adjustment’.
It should be seen that the final image of an object (such as stars, planets or satellites) formed by an astronomical telescope is always prepared concerning the object. But it does not matter whether the image formed by an astronomical telescope is inverted or not, as all the heavenly bodies are usually spherical shapes.
Magnifying Power of an Astronomical Telescope
The Magnifying Power of a telescope is given by:
m = Magnifying Power of an Astronomical Telescope
Where, fo = Focal length of the objective lens
fe = Focal length of the eye-piece lens
And the length (L) of the tube of the telescope is equal to the sum of the focal lengths of the objective lens and the eyepiece. Thus,
L = fo + fe