Oldest Reference to Astronomical Seeing

Oldest Reference to Astronomical Seeing

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I'm writing a paper on astronomical seeing. Sir Isaac Newton identified both the phenomenon and origin of astronomical seeing in his Opticks. He writes:

If the Theory of making Telescopes could at length be fully brought into Practice, yet there would be certain Bounds beyond which Telescopes could not perform. For the Air through which we look upon the Stars, is in a perpetual Tremor; as may be seen by the tremulous Motion of Shadows cast from high Towers, and by the twinkling of the fix'd Stars.

is anyone aware of any older reference from Gilbert, Galileo, Harvey, Ptolemy, Copernicus or Kepler?

Robert Hooke's Micrographia from 1664 has a detailed discussion of "seeing"

The table [of contents], which is at the end of the book, explains that pages 230-232 discuss:

that the Air near the Earth is composed of parts of differing density… this property produces the effects of waving and dancing of Bodies; and of the twinkling of the Stars

Oldest Reference to Astronomical Seeing - Astronomy

Terry J. Mahoney
Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain


Lexicography is defined in the Oxford English Dictionary as ``the writing or compilation of a lexicon or dictionary.'' Among the various senses for lexicon listed in OED2 is, ``The vocabulary proper to some department of knowledge or sphere of activity.'' I define astrolexicography as the application of the practices of lexicography to the astronomical lexicon. However, the discipline of lexicography may be applied to many types of reference works other than dictionaries (for example, ``encyclopaedic dictionaries'', glossaries of technical terms, thesauri, lists of key words, etc.). A full survey of astronomical lexicographical works will be the subject of a future paper. Here I shall limit myself to identifying what I consider to be an important lacuna in astronomical literature.

Most astronomical dictionaries are synchronic (they aim to be up-to-date and eschew obsolete forms), prescriptive (they tell us what the entries are meant to mean rather than how the terms are actually used) and encyclopaedic (they generally include far more information than is necessary for the purposes of definition). There is no diachronic , descriptive dictionary of astronomy, i.e. one that lists and succinctly defines the entire astronomical lexicon from the beginnings of written English to the present day, including all obsolete terms and changes of sense. The work that comes closest to providing such coverage is the OED . The present (second) edition has many gaps in its general scientific coverage which are now being filled for the third edition .

OED2 is the source of most of the historical information about the English language found in other dictionaries. The OED has as its aim ``to present in alphabetical series the words that have formed the English vocabulary from the time of earliest records down to the present day, with all relevant facts concerning their form, sense-history, pronunciation, and etymology'' (Simpson & Weiner 1987). That is a fairly stiff challenge and one which the OED compilers have met admirably. The OED has been criticized for its relatively unrepresentative science coverage (Landau 1989). This problem was partially addressed in the second edition, but only now, with the new revision programme (under way since 1995) and the regular publication of volumes in the OED Additions Series (Simpson & Weiner 1993a,b Proffitt 1997) is the problem being tackled in a thorough and systematic way. A considerable investment is being made in updating and extending the coverage of the astronomical lexicon, and on its completion OED3 will incorporate the widest coverage of astronomical vocabulary from the dawn of the English language to the present time.

The task of producing a new edition of the OED is twofold. First, there is the revision of all the entries in OED2 . Secondly, new senses of existing entries and entirely new entries need to be drafted and incorporated into the body of the dictionary. Proofs for entries are sent out to specialist advisers, who check the accuracy of the definitions, and, where necessary, provide further illustrative quotations (ante-datings are the most important, but sometimes it is necessary to provide more recent quotations, especially for entries that have not been revised since the last century!). Staff editors then modify the entry in the light of the specialists' comments. Suggestions for new entries come from many quarters. The principal criterion is frequency of occurrence in print: the more quotations there are for a new-word candidate, the better its chances of acceptance for inclusion. Concerning astronomy, the number of new words (including old words that were left out of earlier editions) that have been drafted, or are earmarked for drafting, is growing apace, and no realistic estimate of the eventual size of the astronomical lexicon to be included in OED3 can yet be made. Meanwhile, new words and senses are being published, in batches of 3000, in the Additions Series (Simpson & Weiner 1993a,b Proffitt 1997).

In OED2 the coverage of the astronomical lexicon is rather uneven in that a number of common terms are not in. As an example, comparatively few constellation names are included in OED2 this has now been remedied, at least for the 88 ``official'' IAU constellations, all of which now have entries (both for the full Latin names and their IAU abbreviations). As an example, Microscopium now has an entry in its own right with a precise coinage reference to Lacaille in 1752 (the IAU-approved abbreviated form Mic also has an entry). The illustrative quotations for astronomical entries in OED2 are often fairly easily antedated, but this can only be truly remedied by a systematic search of the entire bibliography of astronomy in the English language (i.e. pre-XIV Century to the present day). Some of the entries have not been revised for over a century this is being put right with the present revision programme, which will revise all of the OED in a uniform manner. A good example of an antedating occurs for Medusa's head , which has an earliest quotation dating 1706 in OED2 and 1556 in OED3 (English constellation names are an area that still needs to be charted in detail). The progress of the revision process can be followed in the OED Newsletter , which is published biannually (available at ). Astronomical entries (both for revision and new-word entries) are revised by the Astronomy Adviser who checks that their content is accurate, up to date and fully covers all senses. An important part of this work is to look for antedatings of the illustrative quotations (inter- and post-datings can also occasionally be of use). New quotations are written down on white slips and full bibliographical details given. The slip contents are later keyed into the dictionary database by staff at the OED . The OED is now fully processed by computer (otherwise certain aspects of revising its more than 21000 three-column pages of dense text of OED2 would be a hopelessly unmanageable task on human timescales) nevertheless, the white slip is an essential way of recording data for quotations and new entries for the simple reason that it is the most transportable, silent and user-friendly means of recording written information and can be used in any library! The word or sense under revision will nearly always act as a node for further new-entry suggestions (I refer to this as the nodal approach to corpus building). The drafting of entries (usually done by staff editors) involves providing, apart from the definition, information on the etymology, grammatical function and pronunciation of the term and illustrative quotations.

The OED is a unique work and offers invaluable information to the scholar interested in the development and evolution of the English language. In terms of astronomy OED3 will provide the best available overall picture of the evolution of the English astronomical lexicon, but for finer detail a change of scale will be necessary. The range of spacing between quotations is insufficient for answering, for example, the question of how astronomical terminology varies over a timescale of less than, say, 50 years or more (although the coverage is quite adequate for modern terms). The subtleties of the changes in the astronomical lexicon really need a specialized dictionary based on historical principles which has more space to devote to a denser coverage of the corpus. For this a dedicated Historical Dictionary of Astronomy ( HDA ) is needed.

Before a historical dictionary can be even considered, a corpus of quotations illustrative of all known words and senses is required the compilation of such a corpus from the entire range of printed matter in the English language pertaining to astronomy will require an effort even greater than writing the AHD itself. Apart from astronomical publications as such, astronomical vocabulary occurs in a wide range of other publications (works of literature, navigational treatises, newspaper reports, historical works, etc.). All of this needs to be scanned and quotations recorded for all types of usages of all astronomical terms. This is clearly a long-term goal, and the writing of the HDA cannot await its completion. There are two methods of working towards overall representativeness of the corpus. First there is the systematically thorough reading programme. This is the surest way of building a representative corpus, but it is also the most time-consuming and is better treated as a long-term project aimed at completing an already existing corpus. The second method is to sample current journals and books for synchronic vocabulary and to complement this by a judicious sampling of the literature of past centuries. For historical and some modern astronomical vocabulary, OED2 already provides a very useful database .

The preliminary task of identifying a representative subset of the astronomical lexicon is to compile a wordbase from other astronomical dictionaries (and the OED for obsolete terms). However, this will yield only a subset of the true lexicon and, without further research, would look (and rightly!) like mere plagiarism (see Landau 1989 for an instructive history of English lexicography).

The HDA should aim to describe the entire English lexicon of relevance to astronomy, from its very earliest beginnings to the present rather than prescribing rules for ``correct'' usage. It should also be diachronic rather than synchronic. Above all, the HDA should give concise definitions, including only such information as is necessary for the strict purposes of definition. Our knowledge of astronomical phenomena is constantly evolving ideas that seem perfectly clear and obvious to us today may well be totally overturned tomorrow. A historical dictionary indicates past examples of such vocabulary changes reflecting ``paradigm shifts'' (Kuhn 1970) by tagging past senses as obsolete where necessary and recording all instances of sense changes and multiple meanings (``polysemy''). The HDA should be designed to appeal to a very wide range of users, from the student of literature puzzled by a poetical reference to, say, Astraea's diadem to the professional astronomer who wishes to jog his memory on the meaning of, say, Swan band . Historians of astronomy would certainly benefit from an exhaustive catalogue of obsolete words and senses in their constant vigilance against committing that most embarrassing of historical errors, the anachronism. A record of astronomical usage through the centuries will also provide historians with a valuable chronology of the scientific ideas reflected in the words and senses recorded. The HDA should provide authoritative information of the first recorded use of every word and sense in the astronomical lexicon.

In general, HDA entries should have: i) a highlighted headword ii) a grammatical function label iii) an International Phonetic Alphabet pronunciation guide (perhaps both British and American) iv) pertinent etymological information v) an indication of currency of use: vi) (for modern terms) an indication of whether the term is IAU (or similarly) approved vii) a subject label, especially where the usage is relevant to other fields, such as geology, navigation, literature, etc. viii) one definition per sense ix) highlighting of terms cross-referenced elsewhere in the dictionary x) illustrative quotations (at least one per decade, with greater density of coverage for the modern period) xi) tagging of earliest known occurrence xii) line drawings where these aid comprehensibility, and xiii) appendices of tables containing information on present and past nomenclature systems for planets, stars, nebulae, galaxies, etc. Entries would be arranged alphanumerically, probably according to a system that is both case and font sensitive (to allow for commonly used mathematical symbols and variables), and there should be a thesaurus to indicate interrelations among the entries.

When drafting definitions for a diachronic dictionary of astronomy, the most fundamental rule is to define strictly according to the evidence provided in the quotations. We are interested in how astronomers (and others) use the astronomical lexicon, not in how they think a given term should be used. Hence, major planet will be found to mean either one of the four gas giants or any one of the nine principal planets. Individual astronomers may have their own ideas on what the term ought to mean, but the evidence (and I have plenty) indicates that both the meanings just given are in current use in astronomical publications. Similarly, three definitions may be derived for such an apparently straightforward term as astronomical unit : i) the mean distance of the Earth from the Sun, ii) by dynamical arguments, a value equal to 1.00000003 times the mean distance of the Earth from the Sun, and iii) any other physical unit of measurement (mass, etc.) used in astronomy as a standard quantity.

All quotations must be carefully checked against original copies on paper. Of course, all quotations would need to be keyed into an electronic database for ease of manipulation, and of course the computer keyboard is the best place to start looking for quotation sources, especially in recent research papers. The news of progress in the project to scan historical astronomical literature for access on the ADS (Eichhorn & Kurtz 1998) is most welcome and will be of great assistance to astrolexicographers. Nevertheless, the white slip continues to play a unique role in historical lexicography. Verified hand copying according to well defined editorial rules will also ensure homogeneity of treatment of the entire corpus (which, I repeat, would definitely need to be computerized).

Implicit in all that has been said so far is the need for collections of early books, journals and, especially for very early material, either manuscripts or reliable modern editions of pre-twentieth century works. Modern compilations of historical material need to be examined critically for editorial ``improvement'' of the original for the modern reader's supposed benefit (the Victorians were great ``improvers'' in this respect). If, say, Flamsteed is cited, it is preferable to raise the quotation directly from a source that reflects his original spelling and punctuation rather than a more recent, polished version in this respect the recent publication of Flamsteed's entire correspondence by Forbes et al. (1996, 1997) is an extremely valuable lexicographical resource (not to mention its even greater historical worth). Much of the correspondence of English astronomers of the 15th and 16th centures is still unpublished and contains valuable lexicographical information. It is vital, from all points of view, that this material be efficiently and safely archived for future use. Apart from OED2 , there is little information on how language has been used by scientists in general and on how their use of language has shaped their approach to science. Astronomy is the ideal science for such a study since it has been a recognizable discipline for more than two millenia, whereas physics and chemistry, became recognizable in their modern guise a mere four or five centuries ago. Astronomy was already a fully-fledged science while the English language was evolving from its Anglo-Saxon and medieval French roots to become today's lingua franca of world science. The English astronomical lexicon is therefore the ideal candidate for a dedicated dictionary of astronomy based on historical principles. Apart from the scholarly interest of such a work it would also serve as a solid foundation on which to base all future discussions on terminology and nomenclature.



Kurtz, M. J., & Eichhorn, G. 1998, these proceedings,

Forbes, E. G., Murdin, L., & Willmoth, F. (eds.) 1996, The Correspondence of John Flamsteed, First Astronomer Royal, Vol. I (Bristol, Institute of Physics)

Forbes, E. G., Murdin, L., & Willmoth, F. (eds.) 1997, The Correspondence of John Flamsteed, First Astronomer Royal, Vol. II (Bristol, Institute of Physics)

Landau, S. I. 1989, Dictionaries, 2nd. edn. (Cambridge, Cambridge Univ. Press)

Kuhn, T. 1970 The Structure of Scientific Revolutions, 2nd. edn. (Chicago: Chicago Univ. Press)

Proffitt, M. 1997, Oxford English Dictionary Additions Series, vol. 3 (Oxford: Clarendon Press)

Simpson, J. A. & Weiner, E. S. C. 1987, Oxford English Dictionary, 2nd. edn. (Oxford: Clarendon Press)

Simpson, J., & Weiner, E. 1993a, Oxford English Dictionary Additions Series, vol. 1 (Oxford: Clarendon Press)

Simpson, J., & Weiner, E. 1993b, Oxford English Dictionary Additions Series, vol. 2 (Oxford: Clarendon Press)


. edition The following web sites give further information on progress towards OED3 : (``Inside the OED''),
( OED Newsletter ), and ( OED online --under development). There is also: ( International Journal of Lexicography ).

. database As a by-product of my work as OED Astronomy Adviser I have also started my own astronomical corpus, which now amounts to several thousand entries. This has necessarily been built nodally while treating OED entries in alphabetical sequence however, I have also begun a reading programme with the recently published correspondence of John Flamsteed (see Forbes et al. 1996, 1997). Already, this reading programme has resulted in some interesting ante-datings of OED2 entries.

© Copyright 1998 Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, California 94112, USA

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The Observatory and Its Symbolism

Cheomseongdae has retained its original appearance in the last 1,400 years since it was constructed. Because of this, it reveals valuable information about the nature of ancient Korean observatories to archaeologists. It should be noted that not all archaeologists have agreed that it was an observatory in the past, but this is the dominant view today because of historical and archaeological evidence.

Cheomseongdae is 9.17 meters (30 feet) in height. It consists of a stylobate, a bottle-like tower, and a square top. The square top appears to have been designed to represent a specific Chinese character. The tower is made up of 27 stone tiers, a design which symbolizes Queen Seondeok having been the 27th monarch of the Silla Kingdom.

Cheomseongdae - the oldest astronomical observatory in East Asia. Daereungwon tomb complex, Gyeongju, South Korea. ( photo_HYANG / Adobe stock)

There is a gap or hole in tiers 13 to 15 which is oriented slightly to the southeast. If the stylobate is included as another layer, in addition to the 27 stone tiers, the layers of stone represent the 28 traditional East Asian constellations. If all the layers of the stone tower are added, including the two tiers composing the top section, the layers add up to 30, which is the number of days in a lunar month. Interestingly, the square foundation is made up of 12 stones with three on each of the four corners. This could represent the 12 months of the year and the 4 seasons.

A scaled down model of Cheomseongdae showing its use as an observatory. ( Straitgate / CC BY-SA 3.0 )

The fact that the observatory is filled with symbolism suggests that there was at least some sacred significance to the observatory as well as scientific. Astronomy was not just important for agriculture and timekeeping in the ancient world, but also astrology. For this reason, the observatory likely also had political importance.

Oldest Reference to Astronomical Seeing - Astronomy

In India the first references to astronomy are to be found in the Rig Veda which is dated around 2000 B.C. Vedic Aryans in fact deified the Sun, Stars and Comets. Astronomy was then interwoven with astrology and since ancient times Indians have involved the planets (called Grahas) with the determination of human fortunes. The planets Shani, i.e. Saturn and Mangal i.e. Mars were considered inauspicious.

In the working out of horoscopes (called Janmakundali), the position of the Navagrahas, nine planets plus Rahu and Ketu (mythical demons, evil forces) was considered. The Janmakundali was a complex mixture of science and dogma. But the concept was born out of astronomical observations and perception based on astronomical phenomenon. In ancient times personalities like Aryabhatta and Varahamihira were associated with Indian astronomy.

It would be surprising for us to know today that this science had advanced to such an extent in ancient India that ancient Indian astronomers had recognised that stars are same as the sun, that the sun is center of the universe (solar system) and that the circumference of the earth is 5000 Yojanas. One Yojana being 7.2 kms., the ancient Indian estimates came close to the actual figure.

In Indian languages, the science of Astronomy is today called Khagola-shastra. The word Khagola perhaps is derived from the famous astronomical observatory at the University of Nalanda which was called Khagola. It was at Khagola that the famous 5th century Indian Astronomer Aryabhatta studied and extended the subject.

Aryabhatta is said to have been born in 476 A.D. at a town called Ashmaka in today's Indian state of Kerala. When he was still a young boy he had been sent to the University of Nalanda to study astronomy. He made significant contributions to the field of astronomy. He also propounded the Heliocentric theory of gravitation, thus predating Copernicus by almost one thousand years.

Aryabhatta's Magnum Opus, the Aryabhattiya was translated into Latin in the 13th century. Through this translation, European mathematicians got to know methods for calculating the areas of triangles, volumes of spheres as well as square and cube root. Aryabhatta's ideas about eclipses and the sun being the source of moonlight may not have caused much of an impression on European astronomers as by then they had come to know of these facts throught the observations of Copernicus and Galileo.

But considering that Aryabhatta discovered these facts 1500 years ago, and 1000 years before Copernicus and Galileo makes him a pioneer in this area too. Aryabhatta's methods of astronomical calculations expounded in his Aryabhatta-siddhanta were reliable for practical purposes of fixing the Panchanga (Hindu calendar). Thus in ancient India, eclipses were also forecast and their true nature was perceived at least by the astronomers.

The lack of a telescope hindered further advancement of ancient Indian astronomy. Though it should be admitted that with their unaided observations with crude instruments, the astronomers in ancient India were able to arrive at near perfect measurement of astronomical movements and predict eclipses.

Indian astronomers also propounded the theory that the earth was a sphere. Aryabhatta was the first one to have propounded this theory in the 5th century. Another Indian astronomer, Brahmagupta estimated in the 7th century that the circumference of the earth was 5000 yojanas. A yojana is around 7.2 kms. Calculating on this basis we see that the estimate of 36,000 kms as the earth's circumference comes quite close to the actual circumference known today.

There is an old Sanskrit Sloka (couplet) which is as follows:

"Sarva Dishanaam, Suryaha, Suryaha, Suryaha."

This couplet means that there are suns in all directions. This couplet which describes the night sky as full of suns, indicates that in ancient times Indian astronomers had arrived at the important discovery that the stars visible at night are similar to the Sun visible during day time. In other words, it was recognised that the sun is also a star, though the nearest one. This understanding is demonstrated in another sloka which says that when one sun sinks below the horizon, a thousand suns take its place.

This apart, many Indian astronomers had formulated ideas about gravity and gravitation. Brahmagupta, in the 7th century had said about gravity that "Bodies fall towards the earth as it is in the nature of the earth to attract bodies, just as it is in the nature of water to flow".

About a hundred years before Brahmagupta, another astronomer, Varahamihira had claimed for the first time perhaps that there should be a force which might be keeping bodies stuck to the earth, and also keeping heavenly bodies in their determined places. Thus the concept of the existence of some tractive force that governs the falling of objects to the earth and their remaining stationary after having once fallen as also determining the positions which heavenly bodies occupy, was recognised.

It was also recognised that this force is a tractive force. The Sanskrit term for gravity is Gurutvakarshan which is an amalgam of Guru-tva-akarshan. Akarshan means to be attracted Thus the fact that the character of this force was of attraction was also recognised. This apart, it seems that the function of attracting heavenly bodies was attributed to the sun.

The term Guru-tva-akarshan can be interpreted to mean, 'to the attracted by the Master". The sun was recognised by all ancient people to be the source of light and warmth. Among the Aryans the sun was deifled.

The sun (Surya) was one of the chief deities in the Vedas. He was recognised as the source of light (Dinkara), source of warmth (Bhaskara). In the Vedas he is also referred to as the source of all life, the centre of creation and the centre of the spheres.

The last statement is suggestive of the sun being recognised as the centre of the universe (solar system). The idea that the sun was looked upon as the power that attracts heavenly bodies is supported by the virile terms like Raghupati and Aditya used in referring to the sun.

While the male gender is applied to refer to the sun, the earth (Prithivi, Bhoomi, etc.,) is generally referred to as a female. The literal meaning of the term Gurutvakarshan also supports the recognition of the heliocentric theory, as the term Guru corresponds with the male gender, hence it could not have referred to the earth which was always referred to as a female.

Many ancient Indian astronomers have also referred to the concept of heliocentrism. Aryabhata has suggested it in his treatise Aryabhattiya. Bhaskaracharya has also made references to it in his Magnum Opus Siddhanta-Shiromani.

But it has to be conceded that the heliocentric theory of gravitation was also developed in ancient times (i.e. around 500 B.C.) by Greek astronomers.

What supports the contention that it could have existed in India before the Greek astronomers developed it, is that in Vedic literature the Sun is referred to as the 'centre of spheres' alongwith the term Guru-tva-akarshan which seemingly refers to the sun. The Vedas are dated around 3000 B.C. to 1000 B.C. Thus the heliocentric idea could have existed in a rudimentary form in the days of the Rig Veda and was refined further by astronomers of a later age.

lndian Astronomers like Aryabhatta and Varahamihira who lived between 476 and 587 A.D. made close approaches to the concept of Helicentrism.

In the Surya-Siddhanta, an astronomical text dated around 400 A.D., the following appellations have been given to the sun. "He is denominated the golden wombed (Hiranyagarbha), the blessed as being the generator".

He is also referred to as "The supreme source of light (Jyoti) upon the border of darkness - he revolves. bringing beings into being, the creator of creatures".

The Surya-Siddhanta also says that "Bestowing upon him the scriptures (Vedas) as gifts and establishing him within the egg as grandfather of all worlds, he himself then revolves causing existence". (Quoted from the Surya-Siddhanta, Translated by Rev. Ebenezer Burgess)

Thus we can see that what ancient Indian astronomers say comes close to the heliocentric theory of gravitation, which was a thousand years later articulated by Copernicus and Galileo inviting severe reactions from the clergy in Rome.

History of Astronomy: Observatories and other places

For the homepages of the following observatories see Astronomy.

  • Africa
    • Africa
    • African SkiesA planetarium program
    • History of Mathematics: Alexandria
    • Stull Observatory
    • Five College Astronomy Department
    • The University of Michigan Detroit Observatory
    • Armagh Observatory
    • Armagh Planetarium
    • Scientific Instruments [at Armagh Observatory] and Their Related Correspondence by John McFarland Paper from LISA-II, ESO Garching, 10-12 May 1995
    • Asia
    • Ancient cultures of Asia(20 Oct 1997: disappeared) (collected writings of a 1995 Ancient Astronomical Cosmology class)
    • see also China / Japan
    • The Astronomical History of the Auckland Province, by R. A. McIntosh and John Grigg From The Amateur Astronomer, Vol. 17, No. 2, May 1957, p. 20-22 No. 3, Dec. 1957, p. 40-42 Vol. 18, No. 1, June 1958, p. 3-6 No. 2, Dec. 1958, p. 20-23 No. 3, May 1959, p. 46-48 No. 4, Dec. 1959, p. 60-65.
    • Australia Mainly on the astronomy of the aborigines.
    • The Ancient Australians, writing of a 1995 Ancient Astronomical Cosmology class (20 Oct 1997: disappeared)
    • see also Brisbane / Epping / Kingswood / Mount Stromlo / Perth
    • Observatorium Wendelstein
    • Observatoire de Besançon(in French)
    • Astronomy in Berlin, by Brian Daugherty
    • A brief History of Astronomy in Berlin and the Wilhelm-Foerster-Observatory (Or see German version.)
    • Die Astronomie im geteilten Berlin(in German)
    • Vom Kalender-Patent zum Astrophysikalischen Institut Potsdam - eine Chronik(in German)
    • Berlin and Potsdam(Removed from the Web)
    • Institut für Astronomie und Astrophysik: Überblick über alle Mitglieder des Instituts(in German)All staff members since 1968.
    • Institut für Astronomie und Astrophysik: Überblick über die Abschlüsse am Institut(in German)Habilitationen, Dissertationen, Diplomarbeiten
    • Archenhold-Sternwarte(in German)
    • Archenhold-Sternwarte(in German)
    • Wie das Riesenfernrohr entstand, von Dieter B. Herrmann (in German)About the history of the Archenhold (Treptow) Observatory.
    • The Berlin Trade Exhibition of 1896 (Or see German version.) With short information about the history of the Archenhold (Treptow) Observatory.
    • Wilhelm-Foerster-Sternwarte: Festschrift zum 50-jährigen Jubiläum(in German)
    • see also Heidelberg: Astronomisches Rechen-Institut
    • Birr Castle Demesne (Homepage)
    • Birr Castle Demesne (Information)
    • Lord Rosse and the Birr Castle Telescopes, by Sean McGibbon (13 Jul 1999: contents deleted, refers to the Birr Castle homepage.)
    • Indiana University Astronomy Department / Kirkwood Observatory
    • Astronomical Observatory
    • Iconographic archivesIllustrate the history of science and technology at the University of Bologna, including astronomy. E.g., type in "astronomia" as subject.
    • Ehemalige Sternwarte der Universität Bonn(in German)
    • Astronomy in Bosnia
    • Astronomy at Boston University
    • Sommers-Bausch Observatory
    • Sir Thomas Brisbane Planetarium
    • Konkoly Observatory
    • URANIA Observatory
    • Byurakan Astrophysical Observatory
    • Cagliari Astronomical Observatory
    • Direttori della Stazione Astronomica di Carloforte(in Italian)
    • Institute for Space Reasearch (ISR), Department of Physics & Astronomy, The University of Calgary
    • Institute of Astronomy
    • HM Nautical Almanac Office (HMNAO)
    • Lucasian Chair of MathematicsHeld by Newton, Airy, Hawking, and others.
    • A Brief History of The Lucasian Professorship of Mathematics at Cambridge University
    • Trinity College where Newton wrote Principia
    • Mathematical Sciences in CambridgeIncluding astronomy
    • Cambridge through the centuriesIncluding astronomy
    • see also Greenwich
    • Harvard-Smithsonian Center for Astrophysics
    • Women Astronomers at Harvard at the Turn of the Century, by Michele Nichols and Margaretha Warnicke
    • Radio Astronomy Group, Research Laboratory of Electronics, Massachusetts Institute of Technology
    • MIT Laboratory for Nuclear ScienceFor astrophysical research see especially "The Bruno Rossi Era".
    • see Calgary / Hamilton / London, ON / Toronto / Victoria
    • see also North America
    • South African Astronomical Observatory (SAAO)
    • Catania Astrophysical Observatory and Institute of Astronomy of Catania University
    • University of Illinois Observatory
    • Astronomy at the University of North Carolina at Chapel Hill, 1792-1975
    • History of the Physics Department, 1792-1944Including astronomy
    • Leander McCormick Observatory
    • The Ancient Chinese, writing of a 1995 Ancient Astronomical Cosmology class (20 Oct 1997: disappeared)
    • Asia: China
    • History of Mathematics: ChinaIncluding astronomy
    • The Jesuits in ChinaIncluding astronomical works by Adam Schall von Bell and A. P. Ferdinand Verbiest
    • see also Hong Kong
    • Cincinnati Observatory CenterFormerly: University of Cincinnati Observatory
    • Warner and Swasey Observatory, Case Western Reserve University
    • Melton Memorial Observatory (See also here.)
    • Old Observatory
    • Copenhagen University Observatory
    • Rundetaarn (The Round Tower)
    • Tycho Brahe Planetarium
    • Obserwatorium Astronomiczne Uniwersytetu Jagiellonskiego
    • see Prague
    • see also Slovakia
    • "Big Ear" Radio Observatory (See also Past Projects.)
    • We Wait and Wonder, by John Kraus Reminiscences about "Big Ear" Radio Observatory and SETI.
    • Perkins Observatory
    • A Short History of Perkins Observatory, by Earl W. Phillips, Jr. from EJASA, the Electronic Journal of the Astronomical Society of the Atlantic, Vol. 3, No. 7 - Febr. 1992
    • Centuries of Astronomy: Astronomy in Denmark, by Erling Poulsen
    • See also: Copenhagen
    • Drake Observatory
    • 5 Merrion Square
    • Dublin Institute for Advanced Studies and School of Cosmic Physics
    • City Observatory
    • Africa: Egypt
    • The Sun-ray origin of the Pyramids by James Nasmyth
    • Checklist of Nineteenth-century "studio photographs" of Egypt in the Archive of the Griffith Institute. Part 3 See No.52, Nakht, Scribe and Astronomer of the god Amun
    • Commonwealth Scientific and Industrial Research Organisation (CSIRO), Division of Radiophysics
    • Europe
    • Lowell Observatory
    • McDonald Observatory
    • Kiepenheuer-Institut für Sonnenphysik(in German)
    • The unknown history of Georgian astronomy, by Irakli Simonia
    • Scultetushaus mit Arachne(in German)(17 Oct 1997: disappeared)
    • Astronomie in Gotha(in German)
    • Universitäts-Sternwarte (University Observatory)
    • The Solar Tower
    • Greek Astronomy
    • Greek Astronomy (extra)
    • Greek Mathematics: Astronomical-Mathematical Collectionincluding: Ptolemy, Almagest
    • History of Mathematics: GreeceIncluding astronomy
    • Greek ScienceIncluding astronomy
    • Early Greek Science: Thales to Plato by Michael Fowler Including astronomy
    • Greek Demonstration: The Return of Odysseus and the Elements of Euclid by Andrew Wiesner Including astronomy
    • Astronomical Data Center
    • Goddard Space Flight Center
    • Royal Greenwich Observatory (see also: The Tercentenary Sundial and the Greenwich Water Tanks)
    • Royal Greenwich Observatory Archives, Cambridge University Library
    • Development of astronomy in Greifswald - Short version
    • Physics and Physicists in Greifswald
    • The Fangenturm - astronomy's place of birth in Greifswald
    • History of astronomy in Greifswald - 18th century
    • History of astronomy in Greifswald - 19th century
    • History of astronomy in Greifswald - 20th century
    • Hamburger Sternwarte(in German)
    • Hamburg Observatory: Buildings & TelescopesAlso about their history partly under construction.
    • History of the W.J. McCallion Planetarium
    • Origins of Astronomy in Hawaii, by Walter Steiger
    • Haleakala Observatories
    • The Ancient Hawaiians, writing of a 1995 Ancient Astronomical Cosmology class (20 Oct 1997: disappeared)
    • Astronomisches Rechen-Institut (ARI)(in German)Up to 1945 situated in Berlin.
    • Landessternwarte Heidelberg(in German)
    • Max Planck Institute for Astronomy
    • Robert-Mayer-Volks- und Schulsternwarte Heilbronn(in German)
    • Observatory, University of Helsinki (See also here and here.)
    • Hong Kong Observatory
    • History of Hong Kong Time Service
    • Forty-five years of public observatories in Hungary
    • see also Budapest
    • Island of HvenFrom 1575 to 1597 dedicated to the observatory of Tycho Brahe
    • Tycho Brahe's Castle, Uraniborg, and his Observatory, Stjärneborg
    • Ancient India's Contribution to Astronomy
    • The Context of Vedic India, writing of a 1995 Ancient Astronomical Cosmology class (20 Oct 1997: disappeared)
    • Institute of Astronomy
    • Istanbul University Observatory
    • Istanbul University Observatory(in Turkish longer version)
    • Astronomy in Japan
    • A Short Description of Ancient Japanese Culture and Cosmology, by Mitch Stoltz
    • see also Kiso / Kyoto
    • Astronomy in Jena - Brief Historical Survey
    • Volkssternwarte Urania(in German)
    • Decker-Grebner-Van Zandt Observatory
    • Karlsruher Sternwarte(in German)
    • The First European Observatory in the Modern Era
    • Die erste neuzeitliche Sternwarte Europas(in German)
    • Kieler Sternwarte(in German)
    • Linden ObservatoryA private observatory.
    • Kiso Observatory
    • A Brief History of Korean Astronomy, by Sanghyeon Ahn (See also this version.)
    • History of Astronomy in Korea
    • World Beat : Astronomy in Bloom, by Tae Seog Yoon, Wonyong Han, and Myung Gyoon Lee A history of astronomy in Korea. From Mercury, May/June 1999.
    • Korean History: A Bibliography: Scientific Matters: Astronomy
    • The History of Science in Korea from Korea through Pictures(27 June 2002: disappeared)Including astronomy
    • History of Scientific Development in Korea (Chapter 16.1. of A Window on Korea) (27 June 2002: disappeared)Including astronomy
    • see also Seoul
    • Kvistaberg Observatory
    • Department of Astronomy, Kyoto University(in Japanese)
    • La Plata Astronomical Observatory (or see the Spanish version)
    • Sterrewacht Leiden
    • Observatório Astronómico de Lisboa(in Portuguese, English under construction)
    • A History of the Department of Physics and Astronomy at the University of Western Ontario, by Donald R. Moorcroft (See also Introduction.) From Physics in Canada, Vol. 55, No. 4, July/Aug. 1999, p. 159-176
    • Griffith Observatory 1950/1996
    • Lund Observatory(in Swedish)
    • Petite histoire de l'astronomie à Lyon(in French)
    • Les lunettes et telescopes de l'Observatoire de Lyon(in French)
    • Washburn Observatory
    • Observatorio Astronómico de Madrid(in Spanish)
    • Manila ObservatoryFrom the Catholic Encyclopedia, 1913
    • Patrimoine et histoire de l'Observatoire de Marseille(in English and French)Groupe Patrimoine / History / Old Instruments / Archives / Old Books
    • La succursale di Merate dell'Osservatorio Astronomico di Brera(in Italian)
    • see also: Milan
    • Central America
    • See also: Archaeoastronomy and Ethnoastronomy
    • A Guide to Ancient Near Eastern Astronomy(7 Sep 1998: disappeared)
    • Mesopotamian Year Names, by Marcel Sigrist and Peter Damerow
    • Observatoire de Meudon(in French)
    • see also: Paris
    • Southern Cross Astronomical Observatory
    • Van Vleck Observatory, Department of Astronomy
    • Istituto per ricerche in Fisica Cosmica e Tecnologie Relative(27 Apr 1999: still under construction)
    • Osservatorio Astronomico di Brera
    • Osservatorio Astronomico di Brera(in Italian) (Or see here.)
    • see also: Merate
    • Moletai Observatory(in Lithuanian)
    • see also: Vilnius
    • Trois Siècles d'Astronomie à Montpellier(in French)
    • Virtual Tour of Mt. Hamilton and Lick Observatory (Or see here.) Including additional information about the observatory and its history.
    • A Short History of Mount Stromlo and Siding Spring Observatories
    • Mount Stromlo and Siding Spring Observatories: Observatory History
    • Commonwealth Solar Observatory
    • The First Stromlo Up-hill Bicycle Race, by D.W.N. Stibbs An Autobiographical Account
    • A Wartime Observatory Observed - The Mount Stromlo Community, 1940-1945, by Tim Sherratt and Anne-Marie Condé
    • Mount Wilson Observatory (MWO)
    • MWO: Historical photographs
    • MWO AlmanacSee what happened at MWO on this date!
    • Sternwarte Bogenhausen(in German)
    • see also: Bayrischzell
    • Astronomisches Institut der Universität(in German)
    • Orwell Park Observatory, maintained by the Orwell Astronomical Society
    • Osservatorio Astronomico di Capodimonte(in Italian)
    • History of the Dreyfuss Planetarium
    • Observatoire de la Côte d'Azur(in French)
    • Department of Physics and Astronomy, University of Oklahoma
    • North America
    • Carleton College / Goodsell Observatory
    • Chabot Observatory
    • Institute of Theoretical Astrophysics
    • Steinzeit-Sternwarten in Osnabrück?(in German)
    • Die astronomische Uhr im Dom(in German)
    • Geschichte der Sternwarte Ottobeuren(in German)Public observatory.
    • Padova Observatory
    • Osservatorio Astronomico di Palermo
    • Osservatorio Astronomico di Palermo(in Italian)
    • Osservatorio Astronomico di Palermo(packed PostScript file)
    • Palomar Observatory: Historical photographs
    • Bureau des Longitudes(in French)
    • Institut d'Astrophysique
    • Institut d'Astrophysique(in French)
    • Paris-Meudon-Nançay Observatory
    • Observatoire de Paris-Meudon-Nançay(in French)
    • see also: Meudon
    • The Penllergaer Observatory, South Wales, UK, by S. J. Wainwright
    • North Moor Observatory
    • see also Jubilee
    • Perth Observatory, by Muriel Utting
    • The Flower and Cook Observatory
    • The Heritage Commission
      • A hundred years of science at the Pic du Midi Observatory
      • Photographic exhibit on the history of Pic du Midi observatory
      • Benjamin Baillaud Telescope
      • History of meteorology at the Pic du Midi Observatory
      • Specola Pisana
      • Allegheny Observatory
      • The History of Astronomical Observatories in Poland
      • See also: Cracow / Zielona Góra
      • The Ancient Polynesians, writing of a 1995 Ancient Astronomical Cosmology class (20 Oct 1997: disappeared)
      • Förderverein Großer Refraktor Potsdam(in German)Including information about the Great Refractor of the Astrophysikalisches Observatorium Potsdam
      • Vom Kalender-Patent zum Astrophysikalischen Institut Potsdam - eine Chronik(in German)
      • Die Geschichte der Potsdamer Astrophysik(in German)
      • Sonnenobservatorium Einsteinturm(in German)
      • Einsteinturm (Einstein Tower) (Library of Congress entries)
      • see also: Berlin
      • Astronomical Institute, Charles University (in Czech)Gzipped PostScript file
      • The astronomical clock Orloj
      • The golden age of astronomy in Prague
      • History of Physics in PragueIncluding history of astronomy.
      • Ladd Observatory, Brown University
      • How Brown's large refractor came into being, by Hendrik J. Gerritsen
      • Fire at the Pulkovo Observatory
      • Observatorio Astronomico de Quito(in Spanish English and French versions in preparation)
      • Volkssternwarte Radebeul(in German)
      • Observatory of Friedrich von Hahn (1742-1805)
      • Rattlesnake Mountain Observatory(6 Dec 1996: The old history page has been deleted, a new page is under construction.)
      • The King's Observatory at Richmond
      • Institute of Astronomy(8 June 1998: still under construction)
      • Latvian Astronomical SocietyIncluding a short history of the Astronomical Tower of the University of Latvia.
      • Osservatorio Astronomico di Roma
      • La ricerca astronomica a Roma(in Italian)
      • see also: Vatican City
      • Public Observatory Rothwesten
      • Volkssternwarte Rothwesten(in German)
      • History of the Russian Academy of SciencesAlso about astronomers of the Academy.
      • See also Pulkovo
      • Institute of Space and Astronautical Science (ISAS)
      • Samarkand observatory
      • Observatory of Ulugh Beg (photo)
      • Observatory of Ulugh Beg (photo)
      • SamarkandIncludes information on the observatory, with photos.
      • The Photoalbum: SamarkandIncludes a photo of the observatory.
      • "Old town" - ancient part of SamarkandIncludes a photo of the observatory.
      • Center for Astrophysics and Space Sciences
      • see also: Palomar Mountain
      • Dept. of Astronomy, Seoul National University (or see this other version) (27 June 2002: disappeared)
      • Observatorio Astronómico NacionalReference for a brief history
      • South America
      • Astronomy in Southern AfricaContains some information on history, mainly in the form of files for down-load.
      • Mathematics in St Andrews to 1700Including history of James Gregory's observatory.
      • The Observatory of the High School of Stirling (see also the history page) The telescope may be of historical interest, but no description is given.
      • Stockholm Observatory
      • National Solar Observatory/Sacramento Peak
      • Tartu Observatory(in Estonian, English in preparation)
      • Tartu Observatory pictures
      • Astronomical Institute, Slovak Academy of Sciences
      • Osservatorio Astronomico di Colluriana-TeramoAstronomical Observatory of Collurania
      • Astronomical Observatory
      • Astronomy Department and David Dunlap Observatory, University of Toronto (Or see here.)
      • The Legacy Continues: C. A. Chant and the David Dunlap Observatory, by C. H. Russell From RASC Journal, V. 93, No. 1, February 1999.
      • Toronto Magnetic and Meteorological ObservatoryMade astronomical observations for time calibrations.
      • Toulouse Observatory in Jolimont
      • Observatoire de Toulouse à Jolimont(in French)
      • Astronomical Observatory of Trieste
      • Nordostturm des Schlosses(in German)The old observatory
      • Maxwell HallFormerly an observatory (from 1844 to the 1920s)
      • Horrocks and the Dawn of British Astronomy, by Nicholas Kollerstrom
      • see also: Armagh / Cambridge / Edinburgh / Greenwich / Nacton / Penllergaer / Richmond / St Andrews / Stirling
      • Uppsala
      • See also: Kvistaberg
      • Observatory and Department of Astronomy, University of Illinois at Urbana-Champaign
      • The Smithsonian: 150 Years of Adventure, Discovery, and Wonder by John Conaway, 1995 History of the Smithsonian Institution, including history of astronomy.
      • National Academy of Sciences - National Research CouncilIncluded astronomers, and was of importance for the history of astronomy.
      • The Rise of Scientific Activity in Colonial New England, by Frederick G. Kilgour Including astronomy.
      • Science in the Colonies: Early American Science, by Frederick G. Kilgour Including astronomy.
      • Science in the American Colonies and the Early Republic 1664-1845, by Frederick G. Kilgour Including astronomy.
      • see also Alfred / Amherst / Ann Arbor / Bloomington / Boston / Boulder / Cambridge / Champaign / Chapel Hill / Charlottesville / Cincinnati / Cleveland / Columbia / Delaware / Flagstaff / Fort Davis / Greenbelt / Jubilee / Madison / Miami / Middletown / Mount Hamilton / Mount Wilson / Newark / Northfield / Oakland / Palomar Mountain / Peoria / Philadelphia / Providence / Richland / San Diego / Sunspot / Tuscaloosa / Urbana / Washington / Westford / Williams Bay / Williamstown
      • see also North America
      • Vatican Observatory
      • Vatican ObservatoryFrom the Catholic Encyclopedia, 1913
      • The Vatican Palace, as a Scientific InstituteFrom the Catholic Encyclopedia, 1913
      • Herzberg Institute of Astrophysics / Dominion Astrophysical Observatory
      • Kuffner Observatory
      • Institute for Astronomy / Universitätssternwarte
      • Astronomical Observatory
      • Astronomical Observatory
      • see also: Moletai
      • U.S. Naval Observatory
        • Historical Notes
        • Command History
        • Astrometry Department History
        • Timekeeping at the U.S. Naval Observatory (History)
        • Carter Observatory
        • Johann-Kern-Sternwarte Wertheim(in German)Public observatory.
        • VLBI at Haystack Observatory(26 Apr 1996: still under construction)
        • Yerkes Observatory
        • Yerkes Observatory Virtual Museum
        • Astronomical Figures, by John Franch About the history of Yerkes Observatory. From The University of Chicago Magazine, Feb 1997.
        • Yerkes Observatory: A century of stellar science, by Diana Steele
        • Astronomers who helped make Yerkes Observatory great Both from The University of Chicago Chronicle, March 20, 1997.
        • Hopkins Observatory
        • Science at Williams [College]Including astronomy and Hopkins Observatory.
        • Zielonogórskie Centrum Astronomii (Astronomical Centre of Zielona Gora) (in Polish)

        Information on the history of several sites may also be found in the documents about museums, memorials, historical places and exhibits.

        Find more about history of observatories with Alta Vista.

        Wolfgang R. Dick. Created: 16 Jan 1995. Latest update: 19 Jan 2009

        This guide provides an inventory of the Library of Congress Tracer Bullet series. In addition to their titles, Tracer Bullets were identified by a number indicating the year of publication, followed by the issue number this inventory allows access to the titles by either title or by year and issue number. Links are provided when available to the Tracer Bullets that are accessible online, but some titles may be available only in print format.

        What is a Science Tracer Bullet?

        The Library of Congress Science Tracer Bullet series (ISSN 0090-5232) was an informal and irregular series of library pathfinders published from 1972-2013. They were designed to help someone begin to locate research materials on a subject about which they held only general knowledge.

        These guides were produced by expert reference staff of the Science & Technology Division's Science Reference Section, and, on occasion, by guest librarians, consultants, interns, and volunteers. Most guides were aimed at the undergraduate level, however some, particularly those involving science fair projects, were written with parents and educators in mind. The Tracer Bullets were distributed as government documents to government depository libraries. In 1990 Omnigraphics, Inc. republished 173 of the titles in four volumes.

        For more information on library pathfinders see "Library Pathfinders: a New Possibility for Cooperative Reference Service External ," by Charles H. Stevens, Marie P. Canfield, and Jeffrey J. Gardner, in College and Research Libraries News, v. 34, No 1 (1973).

        What features are included in a Science Tracer Bullet?

        One of the important aspects of the Science Tracer Bullet is that the progress of the information in the format of the bibliographic guide is supposed to mimic the research process itself. The prescribed format defines a scope, gives review articles and basic texts, and then leads the researcher on to suggestions for finding additional information.

        The major features of a Science Tracer Bullet include:

        • a weighted list of subject headings, which can be used in searching a library card catalog
        • a list of basic texts
        • lists of bibliographies, state-of-the-art reports, conference proceedings, or technical reports
        • a list of journals in which one can usually find articles on a particular subject
        • a list of abstracting and indexing services, or databases, useful in finding journal articles and government publications
        • the names and addresses of organizations to contact for additional information
        • a list of selected internet sources

        Why are they called "Tracer Bullets"?

        "Tracer bullets," also called "tracer rounds," are usually loaded as every fifth round in machine gun belts. They provide essential information to soldiers firing at an enemy target by creating a line-of-sight that allows them to track the trajectory of their bullets and adjust their aim. Because these compilations were intended to put a reader "on target," they were called "tracer bullets."

        A Grand Challenge for Austin Amateur Astronomers?

        What is needed to provide every elementary or middle school student in Austin with a good night sky telescope viewing opportunity at least once during their school years?

        Astronomy is both the oldest science and full of new discoveries. Many scientists and engineers started with an interest in astronomy as a child. Even with all of the many spectacular images in the news and available over the Internet, there is nothing as engaging as a first view of the skies through a telescope. It is a first taste of the excitement of learning about the universe through hands on science, a key step in encouraging students to literacy or careers in science. Providing a telescope viewing experience for all students is a worthy goal for amateur astronomers.

        The City of Austin hosts one of the world's major university astronomy departments. UT schedules weekly observing nights at two observatories on campus. Texas schools have astronomy related curriculum goals in all grades. The amateur Austin Astronomical Society has about 500 members and hosts the annual Austin Under the Stars star party and ad hoc outreach events with community partners. Astronomy on Tap organizes monthly short format talks on astronomical topics that are attended by hundreds every month. There are other small groups and individuals doing sidewalk astronomy telescope viewing in town. Even with all of these resources, a large number of students means that relatively few students get chances to have good astronomical observing experiences.

        School districts that include the City of Austin include over a hundred elementary schools and thirty middle schools. Student's spend six years in elementary school and three in middle school. The total student population in the metro area is over 100,000. Motivated students and parents do have some opportunities to use a telescope, but the limited number and accessibility of these result in few students being impacted. The vast majority of students do not have easy access to viewing the night sky through a telescope during their elementary and middle school years. Accessibility often limits these opportunities along class and income lines.

        As amateur astronomers, we understand the transformative power of a first view of the Moon or Saturn through a telescope. We have the knowledge and the equipment to enable these opportunities for students.

        A modest proposal

        I propose that amateur astronomers and educators in Austin initiate a process to

        • Find and characterize the impact of existing organizations and programs that provide night sky telescope and related experiences for Austin students.
        • Decide on an Austin area goals for an astronomical night sky viewing experience for all students.
        • Determine the gaps between those goals and the existing opportunities.
        • Outline a feasible plan to bridge any large gaps and identify the goals, partners, resources, measurements, and actions needed to implement it.

        If this or something similar strikes you as important, get in touch with me and let's see if we can find a way to move forward.

        Content created: 2017-07-02


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        Astronomical observatories

        Ground-based observatories

        Ground-based observatories, located on the surface of Earth, are used to make observations in the radio and visible light portions of the electromagnetic spectrum. Most optical telescopes are housed within a dome or similar structure, to protect the delicate instruments from the elements. Telescope domes have a slit or other opening in the roof that can be opened during observing, and closed when the telescope is not in use. In most cases, the entire upper portion of the telescope dome can be rotated to allow the instrument to observe different sections of the night sky. Radio telescopes usually do not have domes.

        For optical telescopes, most ground-based observatories are located far from major centers of population, to avoid the effects of light pollution. The ideal locations for modern observatories are sites that have dark skies, a large percentage of clear nights per year, dry air, and are at high elevations. At high elevations, the Earth's atmosphere is thinner thereby minimizing the effects of atmospheric turbulence and resulting in better astronomical "seeing". [ 1 ] Sites that meet the above criteria for modern observatories include the southwestern United States, Hawaii, Canary Islands, the Andes, and high mountains in Mexico such as Sierra Negra. [ 2 ] Major optical observatories include Mauna Kea Observatory and Kitt Peak National Observatory in the USA, Roque de los Muchachos Observatory in Spain, and Paranal Observatory in Chile.

        Specific research study performed in 2009 shows that the best possible location for ground-based observatory on Earth is Ridge A – a place in the central part of Eastern Antarctica. [ 3 ] This location provides the least atmospheric disturbances and best visibility.

        Radio observatories

        Beginning in 1930s, radio telescopes have been built for use in the field of radio astronomy to observe the Universe in the radio portion of the electromagnetic spectrum. Such an instrument, or collection of instruments, with supporting facilities such as control centres, visitor housing, data reduction centers, and/or maintenance facilities are called radio observatories. Radio observatories are similarly located far from major population centers to avoid electromagnetic interference (EMI) from radio, TV, radar, and other EMI emitting devices, but unlike optical observatories, radio observatories can be placed in valleys for further EMI shielding. Some of the world's major radio observatories include the Socorro, in New Mexico, USA, Jodrell Bank in the UK, Arecibo, Puerto Rico, Parkes in New South Wales, Australia and Chajnantor in Chile.

        Highest astronomical observatories

        Since the mid-20th century, a number of astronomical observatories have been constructed at very high altitudes, above 4000–5000 m (13,000-16,000 ft). The largest and most notable of these is the Mauna Kea Observatory , located near the summit of a 4205 m (13,796 ft) volcano in Hawaii. The Chacaltaya Astrophysical Observatory in Bolivia, at 5230 m (17,160 ft), was the world's highest permanent astronomical observatory [ 5 ] from the time of its construction during the 1940s until 2009. It has now been surpassed by the new University of Tokyo Atacama Observatory, [ 6 ] an optical-infrared telescope on a remote 5640 m (18,500 ft) mountaintop in the Atacama Desert of Chile.

        Oldest astronomical observatories

        The oldest proto-observatories, in the sense of a private observation post, [ 7 ] include:

        The oldest true observatories, in the sense of a specialized research institute, [ 8 ] [ 9 ] [ 10 ] include:

        • c.150 BC: Observatory at Rhodes, Greece [ 11 ]
        • 825 AD: Al-Shammisiyyah observatory, Baghdad, Iraq
        • 869: Mahodayapuram Observatory , Kerala, India
        • 1259: Maragheh observatory, Azerbaijan (Iran)
        • 1276: Gaocheng Astronomical Observatory, China
        • 1420: Samarqand observatory, Uzbekistan
        • 1442: Beijing Ancient Observatory, China
        • 1577: Istanbul observatory of Taqi al-Din, Turkey
        • 1580: Uraniborg, Denmark
        • 1581: Stjerneborg, Denmark
        • 1642: Panzano Observatory, Italy
        • 1642: Round Tower, Denmark
        • 1633: Leiden Observatory, Netherlands
        • 1667: Paris Observatory, France
        • 1675: Royal Greenwich Observatory, England
        • 1695: Sukharev Tower, Russia
        • 1711: Berlin Observatory, Germany
        • 1724: Jantar Mantar, India
        • 1753: Stockholm Observatory, Sweden
        • 1753: Vilnius University Observatory , Lithuania
        • 1753:
        • 1759: Trieste Observatory, Italy
        • 1757: Macfarlane Observatory, Scotland
        • 1759: Turin Observatory, Italy
        • 1764: Brera Astronomical Observatory, Italy
        • 1765: Mohr Observatory, Indonesia
        • 1774: Vatican Observatory, Vatican
        • 1785: Dunsink Observatory, Ireland
        • 1789: Armagh Observatory, Northern Ireland
        • 1790:
        • 1803:
        • 1811: Tartu Old Observatory, Estonia[ 15 ]
        • 1830/1842: Depot of Charts & Instruments/US Naval Observatory, [ 16 ][ 17 ] USA
        • 1830: Yale University Observatory Atheneum, USA
        • 1836: Hopkins Observatory, Williams College, USA
        • 1839: Pulkovo Observatory, Russia
        • 1839/1847: Harvard College Observatory, USA
        • 1842: Cincinnati Observatory, USA
        • 1873: Quito Astronomical Observatory , Ecuador
        • 1884: McCormick Observatory, USA
        • 1890: Smithsonian Astrophysical Observatory, USA
        • 1894: Lowell Observatory, USA

        Space-based observatories

        Space-based observatories are telescopes or other instruments that are located in outer space, many in orbit around the Earth. Space-based observatories can be used to observe astronomical objects at wavelengths of the electromagnetic spectrum that cannot penetrate the Earth's atmosphere and are thus impossible to observe using ground-based telescopes. The Earth's atmosphere is opaque to ultraviolet radiation, X-rays, and gamma rays and is partially opaque to infrared radiation so observations in these portions of the electromagnetic spectrum are best carried out from a location above the atmosphere of our planet. [ 18 ] Another advantage of space-based telescopes is that, because of their location above the Earth's atmosphere, their images are free from the effects of atmospheric turbulence that plague ground-based observations. [ 19 ] As a result, the angular resolution of space telescopes such as the Hubble Space Telescope is often much smaller than a ground-based telescope with a similar aperture. However, all these advantages do come with a price. Space telescopes are much more expensive to build than ground-based telescopes. Due to their location, space telescopes are also extremely difficult to maintain. The Hubble Space Telescope was serviced by the Space Shuttle while many other space telescopes cannot be serviced at all.

        Airborne observatories

        Airborne observatories have the advantage of height over ground installations, putting them above most of the Earth's atmosphere. But they also have an advantage over space telescopes – the instruments can be deployed, repaired, updated much more quickly and inexpensively. The Kuiper Airborne Observatory and the Stratospheric Observatory for Infrared Astronomy use airplanes to observe in the infrared, which is absorbed by water vapor in the atmosphere. Balloons for X-ray astronomy have been used in a variety of countries.


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