Introduction

A telescope is being used to investigate objects that are really far away from us. Images of faraway things are enlarged with telescopes. An objective lens and an eyepiece lens are used in a basic telescope. The objective lens of a telescope focuses on a parallel beam of light, which then travels through an eyepiece to generate a magnified image. It is made up of two coaxially positioned converging lenses. The objective is the lens that faces the distant object and has a big aperture and focal length. The other is known as the eyepiece since the eye is near to it. It has a shorter focal length and a smaller aperture. The lenses are held in place by tubes.

A brief outline

At its focal plane, the objective creates a real and inverted image of the far object. The eyepiece’s distance from the objective is altered until the final image is generated at the shortest distance vision. If the eye’s position is altered to the point where the final image is generated at infinity. The focal length of the objective lens should be large, while the focal length of the eye lens should be small, to increase the magnification power of an astronomical telescope in a typical adjustment.

The objective lens concentrates light rays to create a true image of a distant object. This image is created in the same plane as the objective lens’s principal focus when light rays cross each other during traveling through the lens. The eyepiece gives the observer looking through the telescope a magnified view of this true image. Because the rays emanating from the eyepiece appear to be coming behind the eyepiece, this magnified representation of the object is called a virtual image. In comparison to the distant object, the virtual image is inverted.

Important concepts

A telescope’s purpose is to increase the angle at which a distant object is placed to subtend at the eye, giving the impression that the object is either larger or closer to the eye. When rays from any point on a very distant object, such as a star that is effectively at infinity, reach the telescope, they are a sensible parallel. As a result, a genuine image I is produced in the objective’s focal plane. The objective’s focal plane is the same as the focal plane of the eye lens. As a result, the picture I serves as an object for the eye lens, and a final virtual, highly magnified image is created at infinity in normal adjustment Clearly, the telescope’s magnification power comes from the fact that the final image at infinity occupies a significantly larger angle in the eye than the distant object. It doesn’t matter if the final image is inverted for astronomical reasons. The objective ought to have a large focal length j, while the eye lens should have a short focal length I. A telescope varies from a compound microscope in this regard.

The objectives, which at their focal length generate an image of an object that is far away from us, and there’s the eyepiece, which serves as a simple magnifier for viewing the image created by the objective. Its length is equal to the sum of the objectives’ and eyepiece’s focal lengths, and its angular magnification is – fo/fe, resulting in an inverted image. When compared to the focal length of the eyepiece, the objective lens of an astronomical telescope has a long focal length. And the objective lens O has a larger aperture than the eyepiece, allowing it to collect more light from the distant object and forming a vivid image of the distant object.

Light from the visible section of the electromagnetic spectrum is gathered and focused by an optical telescope. Optical telescopes enhance the apparent angular size as well as the apparent brightness of distant objects. Telescopes use one or more curved optical elements, commonly composed of glass lenses and/or mirrors, to capture light and other electromagnetic fields and transport it to a focal point where it can be watched, photographed, analyzed, and communicated to a computer.

Radio telescopes are directing radio antennas that gather radio waves to use a widescreen. Occasionally, the dishes are made of a conductive wire mesh with apertures smaller than the wavelength being measured. X-rays are much harder to retrieve and focus than lengthier electromagnetic waves. X-ray optics, such as Wolter telescopes built of ring-shaped ‘glancing’ mirrors made of heavy metals that can only reflect the rays a few degrees, can be used in X-ray telescopes. A piece of a rotating parabola and a hyperbola, or ellipse, are normally used as mirrors.

 

In order to get higher magnification, the objective’s focal length should be as long as possible, while the eyepiece’s focal length should be as short as possible. In normal adjustment, the picture is produced at infinity. The converging lens should be used on both lenses. When viewed via an astronomical telescope, the image of a thing is always inverted. Because we all know that heavenly things are usually spherical in shape, whether the image generated by an astronomy telescope is inverted or not is irrelevant. Students may believe that the telescope’s tube length is equal to the sum of the objective’s focal length and the eyepiece’s focal length. They must realize, however, that this is only true in the situation of exceptional astronomical telescopes in which the object is at infinity and the picture is also at infinity. In most cases, the telescope’s tube length is equal to the sum of the object’s image distance and the eyepiece’s object distance.

Significance of Microscope in NEET exam

The NEET conversations on telescopes are depended upon to uncover and offer responses to the most often introduced demands on the test. With the assistance of notes from skilled examiners in the field, which is given on the Infinity Learn online stage, these can be clarified in fundamental terms. Expecting that understudies manage a raised excitement for the subjects commonly through the educational program, different decision requests are obvious to rehearse.

Prepared experts and talented educators in the subject give responses. The responses are as indicated by CBSE and NCERT rules for the NEET test, helping understudies in accomplishing higher outcomes. The courses are sensibly evaluated, and there are two or three free courses open for new understudies to test. On an equivalent stage, there is a substitute assurance of courses going from kindergarten to twelfth grade, as well as express exercises for horrendous tests like NEET.

Also read: Important Topic of Physics: Wave Optics

Frequently asked questions (FAQs)

Question 1: Give two reasons why a reflecting telescope is better than a refracting telescope.

Answer: Because the objective of a reflecting telescope is a mirror, there is no chromatic aberration. In addition, the image is brighter than that produced by a refracting telescope.

Question-2: What does an astronomy telescope’s final image look like?

Answer: An astronomical telescope is a device made up of two or more optical lenses. An astronomical telescope’s fundamental module consists of two convex lenses known as objective lenses and ocular lenses. Real pictures are created by complicated mirrors. A convex lens can produce an inverted image when light rays arrive from a far point (infinity).

Question 3: What is the mount for an astronomy telescope?

Answer: A telescope mount is a mechanical device that holds a telescope in place. Telescope mounts are built to handle the weight of the telescope by also allowing for precise aiming. Over the years, a variety of mounts have been created, with the majority of focus on devices that can detect the movement of the stars as the Earth revolves. The following are the two basic types of tracking mounts:

• Equatorial mount
• Altazimuth mount