#E1523D

Les lunes. Jean-Jacques Salvador, 1995-1997

Je voulais montrer le visage familier de la lune et garder la précision des images scientifiques que l’on connaît.
Les astronomes ne photographient jamais la pleine lune car, sa surface est alors trop lisse. J’ai donc choisi de la reconstituer quartier par quartier.

Pale Blue dot

Seen from about 6 billion kilometers (3.7 billion miles), Earth appears as a tiny dot (the blueish-white speck approximately halfway down the brown band to the right) within the darkness of deep space.

Sagan pointed out that “all of human history has happened on that tiny pixel (shown here inside a blue circle), which is our only home” (speech at Cornell University, October 13, 1994.)

via: wiki

Johannis Hevelii (Johannes Hevelius) Selenographia sive lunae descriptio, 1647

Johannes Hevelius (also known as Johannes Hewel or Johann Hewelke, 1611-87), son of a wealthy Danzig patrician family, was one of the leading astronomers of his time. At first he studied jurisprudence in Leiden, before he took over his father’s brewery in Danzig, but soon spent all his time with astronomy.
In 1641 Johannes Hevelius set up an observatory in the roof of his Danzig home, which, at that time, was the largest observatory in Europe. He built high-quality astronomical instruments, which he used for topographic examinations of the sun and the planets, particularly the moon. With his main work “Selenographie” (1647), whose splendid illustrations he engraved himself in copperplate, he produced a first, long-standing topographic study of the moon, which does not only contain a detailed description of the moon’s surface, but also a description of the moon phases and the moon’s librations. The Latin term “mare” for moon spots can be traced back to his works.
Johannes Hevelius presented a depiction of the entire celestial sky in his “Prodromus astronomiae”, which was published posthumously in 1690.

A Section of the Constellation Cygnus (August 13, 1885) by Paul and Prosper Henry

Astronomers at the Paris Observatory, the brothers Paul and Prosper Henry inherited in 1872 a project begun twenty years earlier—the mapping of the heavens by means of painstaking observation, calculation, and notation. In a dozen years they charted nearly fifty thousand stars. When, in 1884, their survey approached the Milky Way, the Henry brothers found that the cluster of stars proved far too dense and complex to chart by eye, and they constructed a photographic telescope to produce an exact, objective record of the sky.
That photography might serve astronomy was evident from the very beginning. Daguerre’s standard-bearer François Arago, director of the Paris Observatory, declared in July 1839 that the daguerreotype would eventually accomplish with ease the most delicate and difficult astronomical tasks, such as mapping the surface of the moon. Indeed, before the Henry brothers’ first use of the medium, other photographers had successfully charted lunar geology, solar and lunar eclipses, the transit of Venus, sunspots, the surface of Mars, the rings of Saturn, and the relative position of the brightest stars.
No one, however, had yet recorded stars so distant and faint that they were not visible to the eye. This the Henry brothers achieved in 1885 by constructing a still more powerful photographic telescope, with an extraordinarily precise mechanism for tracking the stars across the night sky during exposures as long as one hour. The resulting photographs, each seemingly infinite expanse showing but a three-degree section of the firmament, remain among the most sublime conceptions of scientific photography.

via: Metropolitan Museum

The Moon by John Adams Whipple, 1857–60

In December 1849, John Whipple made his first photograph of the moon, a daguerreotype taken through the telescope at the Harvard College Observatory in Cambridge. Although he did not make the first lunar photograph in America, in terms of accuracy and aesthetics Whipple produced what were internationally recognized as the most sublime photographs of the moon. This study, made with his partner James Black, recalls the maxim in astronomy: the more clearly one can see an object in space, the more beautiful it looks.

via: Metropolitan Museum

it-sfullofstars:

Radar images of the surface of Venus

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Plate from ‘Systema Saturnium’ by Christiaan Huygens, 1659 

Diagram showing how Saturn’s appearance to us changes due the changing positions of the Earth (E) and Saturn as they orbit the Sun (G).

Introduction by Ronald Brashear (Curator of Science and Technology Rare Books Special Collections Department Smithsonian Institution Libraries)

Christiaan Huygens (pronounced How’-kenz) was born in The Hague, Netherlands, on April 14, 1629. […] He published three mathematical books, produced a manuscript on hydrostatics, wrote a work on collision of elastic bodies, did research on centrifugal force, and invented the pendulum clock. […] Huygens was particularly intrigued by Saturn, mainly because of its puzzling appearance. To an observer using a telescope from the early 17^th century, Saturn did not look like the other planets but at times appeared to have unexplainable protrusions extending out from either side. These protrusions were commonly referred to as ansae or “handles.”
When Huygens initially observed Saturn with his telescope (which provided a magnification of fifty), he […] realized that in order to learn more about the cause of the planet’s odd appearance he would have to construct a telescope with greater magnification and resolution. […]

Huygens was able, in February 1656, to resolve Saturn’s handles into a ring around the planet. Huygens wanted to make more observations of Saturn and develop a coherent theory to explain the ring before he published an official announcement. This would take time […] In the meantime, he penned a very brief treatise, De Saturni luna observatio nova [New observation of a moon of Saturn] (The Hague, 1656).
So as not to give away his explanation, Huygens disguised it in the form of an anagram:

a a a a a a a c c c c c d e e e e e h i i i i i i i l l l l m m n n n n n n n n n o o o o p p q r r s t t t t t u u u u u.

If anyone came forward with the same theory as Huygens, the latter would then reveal his anagram to be:

Annulo cingitur, tenui, plano, nusquam cohaerente, ad eclipticam inclinato [It is surrounded by a thin flat ring, nowhere touching, and inclined to the ecliptic]. 

[…] Huygens confided his Saturnian secret to few people. An important confidant was the well-respected Parisian astronomer Ismael Boulliau (1605-1694). Should anyone else discover Saturn’s ring, Boulliau could act as an independent authority, vouching for Huygens’s claim to priority. […]

In his letter of March 28, 1658, Huygens announced his discovery of the ring to Chapelain and gave him authority to present the announcement to the academy, whose members greeted it with much enthusiasm and praise. Huygens was satisfied with the extent of his research on Saturn by 1659, and his book, Systema Saturnium, was printed and ready for distribution by July of that year.

[…] On page 34, Huygens begins the discussion of the changing and unusual nature of Saturn’s appearance. He discusses earlier observations of the planet going back to Galileo, notes how these observations suffered from the use of inadequate telescopes, and goes into some detail on the hypotheses of Hevelius, Roberval, and Hodierna. After arguing against these explanations, Huygens offers his theory of a thick solid ring circling Saturn at its equator and in equilibrium under Saturn’s gravitational force. He then goes into detail about how the plane of the ring is tilted 20 degrees to the plane of Saturn’s orbit and that the ring maintains a constant orientation as the planet orbits the Sun. This means that the ring’s angle changes with respect to us and thus explained the varying appearance of Saturn. When the ring was edgewise to the Earth it would seem to practically disappear and then slowly the angle would change and the rings would open themselves back up to us. The book ends with Huygens’s observations of all the planets and his calculations of their sizes in relation to the Sun. […]

The concept of a ring around Saturn was generally accepted by 1670. What remained a mystery was the exact nature of the ring. Was it a solid thick ring as Huygens proposed? Always a point of contention, Huygens’s theory was weakened by the discovery of a gap in the supposedly solid ring by Giovanni Domenico Cassini, the director of the Paris Observatory, in 1675. Cassini also believed that the ring was  actually composed of a large number of small satellites orbiting Saturn. In 1785, Pierre Simon, Marquis de Laplace demonstrated the mathematical instablility of solid rings orbiting around Saturn. James Clerk Maxwell wrote a mathematical essay in 1857 which destroyed the notion of a solid ring. His proof noted that the only possible explanation for the ring was that it was composed of small particles orbiting the planet and dense enough to give the appearance of a ring.

Finally, in 1895, Maxwell’s theory was proved by James E. Keeler at the Allegheny Observatory in Pittsburgh. Keeler used a spectroscope to show that the rings were actually rotating around Saturn and that the velocity of rotation could only be explained by a ring like the one described by Maxwell. Today, thanks to investigations made possible by unmanned spacecraft, we now know that the ring system is 270,000 km in diameter, but only a few hundred meters thick. There are four main ring groups and three more faint, narrow ring groups separated by gaps called divisions (the largest one being the Cassini Division). The rings are composed of particles which range from centimeters to tens of meters in size and are mainly made of ice (though there are traces of silicate and carbon minerals).

Plate between pages 32-33 from ‘Systema Saturnium, sive de causis mirandorum Saturni phaenomenon, et comite ejus planeta novo’ [The System of Saturn, or On the matter of Saturn’s remarkable appearance, and its satellite, the new planet] by Christiaan Huygens, 1659 

Observations of Saturn by others prior to Huygens.
I. is an observation by Galileo in 1610.
II. is one by Scheiner in 1614.
III. is one by Riccioli from 1641-1643.
IV-VII. represent suggestions by Hevelius based on his theories.
VIII and IX. are observations by Riccioli from 1648-1650.
X. is an observation by Divini from 1646-1648.
XI. is one by Fontana in 1636.
XII. is one by Gassendi in 1646.
XIII. is from observations by Fontana and others from 1644-1645.

via: Smithsonian Institution Libraries

geneticist:

Rainbow Moon
Date: 7 Dec 1992
This false-color mosaic was constructed from a series of 53 images taken through three spectral filters by Galileo’s imaging system as the spacecraft flew over the northern regions of the Moon in 1989.

The part of the Moon visible from Earth is on the left side in this view. The color mosaic shows compositional variations in parts of the Moon’s northern hemisphere. Bright pinkish areas are highlands materials, such as those surrounding the oval lava-filled Crisium impact basin toward the bottom of the picture. Blue to orange shades indicate volcanic lava flows. To the left of Crisium, the dark blue Mare Tranquillitatis is richer in titanium than the green and orange maria above it. Thin mineral-rich soils associated with relatively recent impacts are represented by light blue colors; the youngest craters have prominent blue rays extending from them.

via: NASA

Prodromus dissertationum cosmographicarum, continens Mysterium Cosmographicum de admirabili proportione orbium coelestium: deque causis coelorum numeri, magnitudinis, motuumque periodicorum genuinis & propriis, demonstratum per quinque regularia corpora goemetrica Kepler, Johannes 1596

via: History of Science

Galileo Galilei. Sidereus Nuncius Magna (Venice, 1610).
Leaf 10 verso with illustrations of the Moon, engraved

On November 30, 1609, Galileo Galilei first turned his telescope toward the moon. He noted the irregularities of the crescent face, and made a drawings to record his discoveries. Over the next eighteen days, he made more drawings and from these chose four for his revolutionary ‘Starry Messenger.’ With the publication of this book, an astonished public learned that the moon was a cratered chunk of elements and not a globe of quintessential perfection.

Found: here

Title: Coelum stellatum in quo asterismi I. Boreales, II. Zodiacales, III. Australes … exhibentur / Opera M. Christophori Semleri…
Author: Semler, Christoph, 1669-1740.
Imprint: Halae Magdeburgicae ; [s.n.] , 1731.
Description: [2] p., [35] leaves of plates : ill. ; 21 cm.
Book location: QB65 .S45 1731 Rare Book Room

Celestial cartographer Christoph Semler is unknown except through his atlas. The Semler atlas is immediately distinguishable from all its predecessors by the black background on the plates. Each plate was printed from a woodblock, on which the outline of the constellation was cut, as well as a symbol for each star.  The rest of the block was uncut, which means it retained ink and printed black.  Each of the 35 woodcuts has a different oriention, which can sometimes be disconcerting, although celestial north is indicated by an arrow on each plate. Some of the illustrations are quite attractive, such as the one that depicts Centaurus, standing over the Southern Cross, engaging Lupus the Wolf.  Semler derived all of his constellations and star positions from the atlas of Hevelius, even including all nine of the new constellation figures that Hevelius introduced.  Hevelius, however, had depicted each  constellation as it would appear if viewed from outside, as on a globe.  Semler showed the constellations as they appear in the sky, from an observer on earth.  So all of Semler’s constellation figures are reversed from those of Hevelius.

Christoph Semler. Coelum Stellatum in Quo Asterismi, 1731. Northern Constellations XXIV - XXVI. Serpentarius, Leo minor and Sextans Uraniae.

found: here

Argo Navis from The Constellations by Abd al-Rahman ibn ‘Umar al-Sufi

Found: here

Pegasus from The Constellations by Abd al-Rahman ibn ‘Umar al-Sufi

Found: here