Skalnate Pleso Atlas of the Heavens
Encyclopedia
The Skalnaté Pleso Atlas of the Heavens (Atlas Coeli Skalnaté Pleso 1950.0) is a set of 16 celestial charts
covering the entire sky. It is named after the Skalnaté Pleso Observatory
in Slovakia
where it was produced. The first versions were published by the Czechoslovak Astronomical Society in 1948; later that year, Sky Publishing Corporation acquired the copyright and began publication in the United States. The charts were hand-drawn by Antonín Bečvář
.
At the time it was first published, the Atlas Coeli was unique in that it contained essentially all non-stellar objects (star clusters, galaxies etc.) that were visible in an 8-inch telescope, in addition to stars brighter than magnitude
7.75. Until the mid 1970s when it went out of print, the Atlas was extremely popular among amateur astronomers, especially those engaged in comet
hunting and the study of variable stars. The Atlas Coeli was also widely used by professional astronomers. Many astronomical observatories still contain copies.
1950.0 and the scale is 1° = 0.75 cm. There are six charts of the equatorial regions on a rectangular graticule, covering declination
s from +25° to -25°; four charts for each hemisphere with straight, converging hour circles and concentric, equally-spaced declination circles covering declinations 20° - 65°; and, for each hemisphere, a circumpolar chart covering declination 65° to the pole. All stars brighter than 7.75 magnitude are included, for a total of 32,571. The stellar magnitudes are indicated by circles with graded sizes. Double
and multiple star
s are identified and visual binaries are differentiated from spectroscopic binaries. All known variable stars are identified, including nova
e that had maxima brighter than magnitude 7.75 (totalling 443). 249 star clusters are shown and their relative size indicated. All known globular cluster
s are shown. 1,130 extragalactic systems are included as are many Galactic objects including planetary nebula
e. Bright and dark diffuse nebulae are shown, and the actual outlines of those larger than 10' in diameter are painstakingly drawn. The Milky Way
and prominent obscuring clouds within it are indicated by isophotic lines. Constellation
boundaries are clearly but unobtrusively drawn. The celestial equator
and ecliptic
are indicated. The brightest radio sources
are also shown.
The Atlas Coeli is famous for its clean appearance and for the wealth of data it contains. The drawing is beautifully and precisely done and the printing is excellent. Many other star charts have been strongly influenced by the style of the Atlas Coeli. For instance, the popular Sky Atlas 2000.0 of Wil Tirion
adopted the symbols for various types of objects, the division of scales, and the script directly from the Atlas Coeli.
Much of the work was carried out by a volunteer group of students at the Observatory; the final plotting of the Atlas, which was entirely hand-drawn, was the work of Bečvář. Positional and magnitude data were taken from a number of existing catalogs, including the Henry Draper catalog, the Aitken
New General Catalog of Double Stars, and the Boss
General Catalog. About ten photographic atlases were used as well. To plot each of the objects, one of 20 stencil patterns was selected and positioned. It was also necessary to compute the shift in the apparent position of each of the objects to epoch 1950.0. About 3,000 man-hours of work were involved.
; apparent magnitude (Revised Harvard Photometric [RHP, or HR] system); absolute magnitude
; spectral type
(Mt. Wilson scheme); parallax; radial velocity; standard name of star and its constellation; and notes indicating if the star is double or variable.
The Catalogue includes a number of other tables with data on double and multiple stars, galactic and extragalactic nebulae, and radio sources.
Bečvář went on to create a number of other atlases: Atlas Eclipticalis (the celestial region between -30 and +30° declination on 32 maps), Atlas Borealis (the celestial region north of declination +30° on 24 maps), and Atlas Australis (the celestial region south of declination -30° on 24 maps). Stellar clusters and nebulae are not plotted, but a six-color press was used to distinguish six basic spectral classes of stars. These atlases were especially helpful in the early days of position measurements of artificial satellite.
Star chart
A star chart is a map of the night sky. Astronomers divide these into grids to use them more easily. They are used to identify and locate astronomical objects such as stars, constellations and galaxies. They have been used for human navigation since time immemorial...
covering the entire sky. It is named after the Skalnaté Pleso Observatory
Skalnaté Pleso Observatory
Observatórium Skalnaté pleso is an astronomical observatory in Slovakia. There is also a meteorological observatory. It is near Tatranská Lomnica and has IAU observatory code 056. The name means "Rocky Lake" .The observatory produced the popular sky atlas Skalnate Pleso Atlas of the Heavens by A...
in Slovakia
Slovakia
The Slovak Republic is a landlocked state in Central Europe. It has a population of over five million and an area of about . Slovakia is bordered by the Czech Republic and Austria to the west, Poland to the north, Ukraine to the east and Hungary to the south...
where it was produced. The first versions were published by the Czechoslovak Astronomical Society in 1948; later that year, Sky Publishing Corporation acquired the copyright and began publication in the United States. The charts were hand-drawn by Antonín Bečvář
Antonín Bečvář
Antonín Bečvář was a Czech astronomer who was active in Slovakia. He was born in Stará Boleslav. Among his chief achievements is the foundation of the Skalnaté Pleso Observatory and the discovery of the comet C/1947 F2 .Bečvář is particularly important for his star charts: he led the compilation...
.
At the time it was first published, the Atlas Coeli was unique in that it contained essentially all non-stellar objects (star clusters, galaxies etc.) that were visible in an 8-inch telescope, in addition to stars brighter than magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
7.75. Until the mid 1970s when it went out of print, the Atlas was extremely popular among amateur astronomers, especially those engaged in comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
hunting and the study of variable stars. The Atlas Coeli was also widely used by professional astronomers. Many astronomical observatories still contain copies.
Description
The Atlas Coeli covers both hemispheres with 16 charts. The coordinate system is referred to equinoxEquinox
An equinox occurs twice a year, when the tilt of the Earth's axis is inclined neither away from nor towards the Sun, the center of the Sun being in the same plane as the Earth's equator...
1950.0 and the scale is 1° = 0.75 cm. There are six charts of the equatorial regions on a rectangular graticule, covering declination
Declination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
s from +25° to -25°; four charts for each hemisphere with straight, converging hour circles and concentric, equally-spaced declination circles covering declinations 20° - 65°; and, for each hemisphere, a circumpolar chart covering declination 65° to the pole. All stars brighter than 7.75 magnitude are included, for a total of 32,571. The stellar magnitudes are indicated by circles with graded sizes. Double
Double star
In observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope. This can happen either because the pair forms a binary star, i.e...
and multiple star
Multiple star
A multiple star consists of three or more stars which appear from the Earth to be close to one another in the sky. This may result from the stars being physically close and gravitationally bound to each other, in which case it is physical, or this closeness may be merely apparent, in which case...
s are identified and visual binaries are differentiated from spectroscopic binaries. All known variable stars are identified, including nova
Nova
A nova is a cataclysmic nuclear explosion in a star caused by the accretion of hydrogen on to the surface of a white dwarf star, which ignites and starts nuclear fusion in a runaway manner...
e that had maxima brighter than magnitude 7.75 (totalling 443). 249 star clusters are shown and their relative size indicated. All known globular cluster
Globular cluster
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
s are shown. 1,130 extragalactic systems are included as are many Galactic objects including planetary nebula
Planetary nebula
A planetary nebula is an emission nebula consisting of an expanding glowing shell of ionized gas ejected during the asymptotic giant branch phase of certain types of stars late in their life...
e. Bright and dark diffuse nebulae are shown, and the actual outlines of those larger than 10' in diameter are painstakingly drawn. The Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
and prominent obscuring clouds within it are indicated by isophotic lines. Constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
boundaries are clearly but unobtrusively drawn. The celestial equator
Celestial equator
The celestial equator is a great circle on the imaginary celestial sphere, in the same plane as the Earth's equator. In other words, it is a projection of the terrestrial equator out into space...
and ecliptic
Ecliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...
are indicated. The brightest radio sources
Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
are also shown.
The Atlas Coeli is famous for its clean appearance and for the wealth of data it contains. The drawing is beautifully and precisely done and the printing is excellent. Many other star charts have been strongly influenced by the style of the Atlas Coeli. For instance, the popular Sky Atlas 2000.0 of Wil Tirion
Wil Tirion
Wil Tirion is a Dutch uranographer . His most famous work, Sky Atlas 2000.0, is renowned by astronomers for its accuracy and beauty. The second edition of his most complete work, Uranometria 2000.0, was published in 2001 by Willmann-Bell. He is also responsible for the sky charts found in many...
adopted the symbols for various types of objects, the division of scales, and the script directly from the Atlas Coeli.
Origin
The Atlas Coeli was created in the period 1947-1948 at the Skalnaté Pleso Observatory in Slovakia (then Czechoslovakia) under the direction of Antonín Bečvář, based on an idea of Czechoslovakian amateur astronomer Josef Klepesta.Much of the work was carried out by a volunteer group of students at the Observatory; the final plotting of the Atlas, which was entirely hand-drawn, was the work of Bečvář. Positional and magnitude data were taken from a number of existing catalogs, including the Henry Draper catalog, the Aitken
Robert Grant Aitken
Robert Grant Aitken was an American astronomer.He worked at Lick Observatory in California. He systematically studied double stars, measuring their positions and calculating their orbits around one another...
New General Catalog of Double Stars, and the Boss
Benjamin Boss
Benjamin Boss was anAmerican astronomer.He was born to Lewis Boss and Helen M. Boss. After attending The Albany Academy, he graduated from Harvard University in 1901 and worked at Dudley Observatory until 1905. Following a year at the U. S. Naval Observatory in Washington, D.C., he became director...
General Catalog. About ten photographic atlases were used as well. To plot each of the objects, one of 20 stencil patterns was selected and positioned. It was also necessary to compute the shift in the apparent position of each of the objects to epoch 1950.0. About 3,000 man-hours of work were involved.
The Atlas Catalogue
Immediately after publication of the Atlas Coeli, a supplement was produced called the Atlas Coeli II - Catalogue 1950.0. The Catalog contains data and descriptions of approximately 12000 objects plotted in the Atlas . All stars to magnitude 6.25 are included as well as a large number of the non-stellar objects. Stellar data includes the 1950.0 coordinates with their annual variations; proper motionProper motion
The proper motion of a star is its angular change in position over time as seen from the center of mass of the solar system. It is measured in seconds of arc per year, arcsec/yr, where 3600 arcseconds equal one degree. This contrasts with radial velocity, which is the time rate of change in...
; apparent magnitude (Revised Harvard Photometric [RHP, or HR] system); absolute magnitude
Absolute magnitude
Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...
; spectral type
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
(Mt. Wilson scheme); parallax; radial velocity; standard name of star and its constellation; and notes indicating if the star is double or variable.
The Catalogue includes a number of other tables with data on double and multiple stars, galactic and extragalactic nebulae, and radio sources.
Publication history
A six-color improved version of the Atlas was published by the Czechoslovak Academy of Sciences in 1956. The copyright to publish the Atlas outside of Czechoslovakia was purchased by Sky Publishing Corporation in 1949. Under this copyright, the Atlas was published in a series of editions, from a luxurious, full-color version to a black-and-white version of size 23x15in. Pursuant to Bečvář's request, royalties were used to purchase special astronomical photographic plates for the Skalnaté Observatory.Bečvář went on to create a number of other atlases: Atlas Eclipticalis (the celestial region between -30 and +30° declination on 32 maps), Atlas Borealis (the celestial region north of declination +30° on 24 maps), and Atlas Australis (the celestial region south of declination -30° on 24 maps). Stellar clusters and nebulae are not plotted, but a six-color press was used to distinguish six basic spectral classes of stars. These atlases were especially helpful in the early days of position measurements of artificial satellite.