Definitions for heliometer
ˌhi liˈɒm ɪ tərhe·liome·ter

Princeton's WordNetRate this definition:0.0 / 0 votes

1. heliometernoun

   an instrument used to measure the angular separation of two stars that are too far apart to be included in the field of view of an ordinary telescope

WiktionaryRate this definition:0.0 / 0 votes

1. heliometernoun

   An astronomical instrument, based on a telescope, for measuring the diameter of the sun; now used to measure the angular distance between stars and other celestial bodies.

2. Etymology: helio-, from Ἥλιος, from ἥλιος + meter, from mètre, from μέτρον.

WikipediaRate this definition:0.0 / 0 votes

1. Heliometer

   A heliometer (from Greek ἥλιος hḗlios "sun" and measure) is an instrument originally designed for measuring the variation of the sun's diameter at different seasons of the year, but applied now to the modern form of the instrument which is capable of much wider use.The basic concept is to introduce a split element into a telescope's optical path so as to produce a double image. If one element is moved using a screw micrometer, precise angle measurements can be made. The simplest arrangement is to split the object lens in half, with one half fixed and the other attached to the micrometer screw and slid along the cut diameter. To measure the diameter of the sun, for example, the micrometer is first adjusted so that the two images of the solar disk coincide (the "zero" position where the split elements form essentially a single element). The micrometer is then adjusted so that diametrically opposite sides of the two images of the solar disk just touch each other. The difference in the two micrometer readings so obtained is the (angular) diameter of the sun. Similarly, a precise measurement of the apparent separation between two nearby stars, A and B, is made by first superimposing the two images of the stars and then adjusting the double image so that star A in one image coincides with star B in the other. The difference in the two micrometer readings so obtained is the apparent separation or angular distance between the two stars. The first application of the divided object-glass and the employment of double images in astronomical measures is due to Servington Savery of Shilstone in 1743. Pierre Bouguer, in 1748, originated the true conception of measurement by double image without the auxiliary aid of a filar micrometer, that is by changing the distance between two object-glasses of equal focus. John Dollond, in 1754, combined Savary's idea of the divided object-glass with Bouguer's method of measurement, resulting in the construction of the first really practical heliometers. As far as we can ascertain, Joseph von Fraunhofer, some time not long before 1820, constructed the first heliometer with an achromatic divided object-glass, i.e. the first heliometer of the modern type.The first successful measurements of stellar parallax (to determine the distance to a star) were made by Friedrich Bessel in 1838 for the star 61 Cygni using a Fraunhofer heliometer. This was the 6.2-inch (157.5 mm) aperture Fraunhofer heliometer at Königsberg Observatory built by Joseph von Fraunhofer's firm, though he did not live to see it delivered to Bessel. Although the heliometer was difficult to use, it had certain advantages for Bessel including a wider field of view compared to other great refractors of the period, and overcame atmospheric turbulence in measurements compared to a filar micrometer.

ChatGPTRate this definition:0.0 / 0 votes

1. heliometer

   A heliometer is a type of telescope originally designed for measuring the variation of the sun's diameter at different seasons of the year, but applied now to the fine measurement of angles between stars and other astronomical objects. It essentially consists of a telescope in which the objective lens is split into two halves that can be moved apart or together.

Webster DictionaryRate this definition:0.0 / 0 votes

1. Heliometernoun

   an instrument devised originally for measuring the diameter of the sun; now employed for delicate measurements of the distance and relative direction of two stars too far apart to be easily measured in the field of view of an ordinary telescope

2. Etymology: [Helio- + -meter: cf. F. hliomtre.]

WikidataRate this definition:0.0 / 0 votes

1. Heliometer

   Heliometer is an instrument originally designed for measuring the variation of the sun's diameter at different seasons of the year, but applied now to the modern form of the instrument which is capable of much wider use. The basic concept is to introduce a split element into a telescope's optical path so as to produce a double image. If one element is moved using a screw micrometer, precise angle measurements can be made. The simplest arrangement is to split the object lens in half; with one half fixed and the other attached to the micrometer screw and slid along the cut diameter. To measure the diameter of the sun, for example, the micrometer is adjusted so that the two images of the solar disk just touch each other. Similarly, a precise measurement of the apparent separation between two nearby stars, A and B, is made by adjusting the double image so that A in one image touches B in the other. The first application of the divided object-glass and the employment of double images in astronomical measures is due to Servington Savary from Exeter in 1743. Pierre Bouguer, in 1748, originated the true conception of measurement by double image without the auxiliary aid of a filar micrometer, that is by changing the distance between two object-glasses of equal focus. John Dollond, in 1754, combined Savary's idea of the divided object-glass with Bouguer's method of measurement, resulting in the construction of the first really practical heliometers. As far as we can ascertain, Joseph von Fraunhofer, some time not long before 1820, constructed the first heliometer with an achromatic divided object-glass, i.e. the first heliometer of the modern type.

Chambers 20th Century DictionaryRate this definition:0.0 / 0 votes

1. Heliometer

   hē-li-om′e-tėr, n. an instrument by which the diameters of the heavenly bodies can be measured with great accuracy.—adjs. Heliomet′ric, -al. [Gr. hēlios, sun, metron, a measure.]

Dictionary of Nautical TermsRate this definition:0.0 / 0 votes

1. heliometer

   An instrument designed for the accurate measurement of the diameters of the sun or planets.

Matched Categories

1. • Measuring Instrument

How to pronounce heliometer?

1. Alex

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   Mark

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   Daniel

   British

   Libby

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   Mia

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How to say heliometer in sign language?

Numerology

1. Chaldean Numerology

   The numerical value of heliometer in Chaldean Numerology is: 5

2. Pythagorean Numerology

   The numerical value of heliometer in Pythagorean Numerology is: 2

References

1. ^ Princeton's WordNet
   http://wordnetweb.princeton.edu/perl/webwn?s=heliometer
2. ^ Wiktionary
   https://en.wiktionary.org/wiki/Heliometer
3. ^ Wikipedia
   https://en.wikipedia.org/wiki/Heliometer
4. ^ ChatGPT
   https://chat.openai.com
5. ^ Webster Dictionary
   https://www.merriam-webster.com/dictionary/heliometer
6. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=heliometer
7. ^ Chambers 20th Century Dictionary
   https://www.gutenberg.org/files/37683/37683-h/37683-h.htm#:~:text=heliometer
8. ^ Dictionary of Nautical Terms
   https://www.gutenberg.org/cache/epub/26000/pg26000-images.html#:~:text=heliometer