{"id":16194,"date":"2014-10-05T18:09:38","date_gmt":"2014-10-05T12:39:38","guid":{"rendered":"http:\/\/astron-soc.in\/outreach\/?page_id=16194"},"modified":"2015-07-06T13:01:56","modified_gmt":"2015-07-06T07:31:56","slug":"different-types-of-telescopes","status":"publish","type":"page","link":"https:\/\/astron-soc.in\/outreach\/activities\/make-your-own-telescope\/different-types-of-telescopes\/","title":{"rendered":"Different types of telescopes"},"content":{"rendered":"

There are two types of telescopes that one normally makes as a beginner. \u00a0A simple refracting type, very similar to what Galileo Galilee <\/a>used in 1610, and a reflecting type that was developed by Newton.<\/p>\n

The refracting type uses a lens to collect light where as concave mirror is used for the purpose in reflecting type telescope.<\/p>\n

Refracting type<\/a>:\u00a0 The first of this kind of telescope was used by Galileo. It\u00a0 had a convex lens as objective and a concave lens was used as eyepiece.\u00a0 This\u00a0optical configuration gave a rather small field of view.<\/p>\n

\"refracting_2\"<\/p>\n

It was later modified by Johannes Kepler<\/a> who replaced the concave lens of the eyepiece by a convex lens. This configuration gave better field of view but the images are inverted or upside down, which is no consequence for astronomical observation.<\/p>\n

\"refracting_1\"<\/p>\n

This system suffered another problem, called chromatic aberration.\u00a0 When the light passes through a lens it breaks into its component colours and rays of different colours focus at different distances. Therefore the images are not quite sharp.<\/p>\n

\"refracting_3\"<\/p>\n

English optician John Dollond<\/a> solved this problem by adding a concave lens after the convex lens of the objective.\u00a0 Such lens is called an achromatic lens.<\/p>\n

\"refracting_4\"<\/p>\n

During the\u00a0 International year of Astronomy in 1999, various institutions and clubs across the country conducted telescope making workshop of this kind of telescope. \u00a0For example, IUCAA conducted a serious of workshop for making what they called the\u00a0G++ telescope<\/a>.\u00a0 This telescope had an achromatic lens and a 45 degree mirror. This was placed on simple stand.\u00a0 Using a telescope of this kind one can see the moons of Jupiter, phases of Venus, some bright nebulae, and even some galaxies.<\/p>\n

Reflecting type<\/a>:\u00a0 Isaac Newton<\/a> made the first such\u00a0telescope. \u00a0This is also the most popular type among amateur astronomers.\u00a0 The process involves making a concave mirror and placing\u00a0the mirror with the eye piece etc in a suitable mount.<\/p>\n

Normally, amateur astronomers make concave mirror of roughly 150 mm (or 6 inch) in diameter. It takes about 3 to 4 weeks to make such a telescope. \u00a0In the recent past, mirrors of 100 mm (4 inch) have become popular as these can be made in just about a week. \u00a0Check this link\u00a0Amateur Telescope Making<\/a>\u00a0– India.<\/p>\n","protected":false},"excerpt":{"rendered":"

There are two types of telescopes that one normally makes as a beginner. \u00a0A simple refracting type, very similar to what Galileo Galilee used in 1610, and a reflecting type that was developed by Newton. The refracting type uses a lens to collect light where as concave mirror is used for the purpose in reflecting […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":128,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_uag_custom_page_level_css":"","footnotes":""},"class_list":["post-16194","page","type-page","status-publish","hentry","post"],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"post-thumbnail":false,"vantage-thumbnail-no-sidebar":false,"vantage-slide":false,"vantage-carousel":false,"vantage-grid-loop":false,"rpwe-thumbnail":false,"sow-carousel-default":false},"uagb_author_info":{"display_name":"admin","author_link":"https:\/\/astron-soc.in\/outreach\/author\/admin\/"},"uagb_comment_info":0,"uagb_excerpt":"There are two types of telescopes that one normally makes as a beginner. \u00a0A simple refracting type, very similar to what Galileo Galilee used in 1610, and a reflecting type that was developed by Newton. The refracting type uses a lens to collect light where as concave mirror is used for the purpose in reflecting…","rttpg_featured_image_url":null,"rttpg_author":{"display_name":"admin","author_link":"https:\/\/astron-soc.in\/outreach\/author\/admin\/"},"rttpg_comment":0,"rttpg_category":false,"rttpg_excerpt":"There are two types of telescopes that one normally makes as a beginner. \u00a0A simple refracting type, very similar to what Galileo Galilee used in 1610, and a reflecting type that was developed by Newton. The refracting type uses a lens to collect light where as concave mirror is used for the purpose in reflecting…","_links":{"self":[{"href":"https:\/\/astron-soc.in\/outreach\/wp-json\/wp\/v2\/pages\/16194","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/astron-soc.in\/outreach\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/astron-soc.in\/outreach\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/astron-soc.in\/outreach\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/astron-soc.in\/outreach\/wp-json\/wp\/v2\/comments?post=16194"}],"version-history":[{"count":1,"href":"https:\/\/astron-soc.in\/outreach\/wp-json\/wp\/v2\/pages\/16194\/revisions"}],"predecessor-version":[{"id":16195,"href":"https:\/\/astron-soc.in\/outreach\/wp-json\/wp\/v2\/pages\/16194\/revisions\/16195"}],"up":[{"embeddable":true,"href":"https:\/\/astron-soc.in\/outreach\/wp-json\/wp\/v2\/pages\/128"}],"wp:attachment":[{"href":"https:\/\/astron-soc.in\/outreach\/wp-json\/wp\/v2\/media?parent=16194"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}