IUCCA Lecture Demonstration Programme

Date: 9th August, 2014.

Venue: Chandrasekhar Auditorium, IUCAA

Topic: The World of Telescopes

Speaker: Mr. Samir Dhurde, IUCAA 

Representative teacher- Mrs. Monika Mishra

Madhav Rawal-XB

Prathamesh Vyas-XA

Yash Kothadiya-XB

Anirudh Karnik-VIII B

Sarthak Kapoor-VIII B

Om Nankar-VIII C

Saahil Behere-VIII C

Shreshtha Kulkarni-VIII B

Atharva Dongre-IX B

Atharva Chavan-IX A

Nupur Lanjekar-VIII B

Shown pictures of Milky Way Galaxy.               

Bioluminescence-The biochemical emission of light by living organisms such as glow-worms and deep-sea fish.

 Aim of a Telescope-

Making distant objects look-

-Bigger

-Brighter

-Sharper than they appear to your eye

        b) It is like a funnel collects light.

      6. Different types of Telescopes

The earliest recorded working telescopes were the refracting telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals: Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, and Jacob Metius of Alkmaar.  Galileo heard about the Dutch telescope in June 1609, built his own within a month, and greatly improved upon the design in the following year.

The idea that the objective, or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors—reduction of spherical aberration and no chromatic aberration—led to many proposed designs and several attempts to build reflecting telescopes. In 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name, the Newtonian reflector.

Refractor- Atazmuth

Compound- Equatorial Fork

Newtonian Reflector- German Equatorial

Refracting

Commonly known as refractors, telescopes of this kind are used to examine the visible-light region of the electromagnetic spectrum. Typical uses include viewing the Moon, other objects of the solar system such as Jupiter and Mars, and double stars. The name refractor is derived from the term refraction, which is the bending of light when it passes from one medium to another of different density–e.g., from air to glass. The glass is referred to as a lens and may have one or more components. The physical shape of the components may be convex, concave, or plane-parallel. Figure illustrates the principle of refraction and the term focal length. The focus is the point, or plane, at which light rays from infinity converge after passing through a lens and traveling a distance of one focal length. In a refractor, the first lens through which light from a celestial object passes is called the objective lens. It should be noted that the light will be inverted at the focal plane. A second lens, referred to as the eyepiece lens, is placed behind the focal plane and enables the observer to view the enlarged, or magnified, image. Thus, the simplest form of refractor consists of an objective and an eyepiece.

Reflecting

A reflecting telescope (also called a reflector) is an optical telescope which uses a single or combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic aberration. Although reflecting telescopes produce other types of optical aberrations, it is a design that allows for very large diameter objectives. Almost all of the major telescopes used in astronomy research are reflectors. Reflecting telescopes come in many design variations and may employ extra optical elements to improve image quality or place the image in a mechanically advantageous position. Since reflecting telescopes use mirrors, the design is sometimes referred to as a “catoptric” telescope.

World’s largest reflector

Diameter- 40 inches (102 cm)

Yerkes observatory, Wisconsin, USA.

7. Explained the electromagnetic spectrum-

8. Explained Nebula

9. Andomeda Galaxy (closest)

10. Vainu Bappu Telescope(Indian)-

Manali Kallat Vainu Bappu (August 10, 1927 – August 19, 1982) was an Indian astronomer and president of the International Astronomical Union. Bappu helped establish several astronomical institutions in India——including the Vainu Bappu Observatory named after him—and also contributed to the establishment of the modern Indian Institute of Astrophysics. In 1957, he discovered the Wilson-Bappu effect jointly with American astronomer Olin Chaddock Wilson.

He is regarded as the father of modern Indian astronomy.

Hanle Chandra Telescope

IUCAA Girawali Observatory

Udaipur Solar Observatory

ARIES, Manorapeak, Nainital

GMRT, Narayangaon

HAGAR, Hanle

Astrosat (satellite)

Gran Telescopio Canaries

Diameter-10.4m(largest area used), Spain

Keck Telescopes,

Mauna KeaHawai, USA

Very Large Telescopes,

Paranal, Chile

Diameter-8.2mX4Units

Large Binocular Telescope(largest)

Arizona, USA, 

Diameter-8.4X2Units

South African Largest Telescope

Diameter-11mX9.8m

Suthernland, RSA

Hobby Eberly Telescope

Suthernland, RSA

Diameter-11mX9.8m

Construction pic of telescopes

European Extremely Large Telescope

Paranal, Chile

Diameter- 39.3m

Thirty Meter Telescope

Diameter-30m

Maunakea, Hawaii, USA

(13 International Telescopes)

Adaptive optics(creating artificial star)