Download Who actually invented the astronomical telescope?

25/07/2016
The telescope has
revolutionised science and
astronomy.
Who invented the telescope?
Il telescopio
rifrattore nella
storia
“There is no nation which has not
claimed for itself the remarkable
invention of the telescope: indeed, the
French, Spanish, English, Italians, and
Hollanders have all maintained that
they did this.”
Domenico Licchelli
Scuola Estiva di Astronomia 2016 – 21 Luglio
Pierre Borel, De vero telescopii inventore (1656)
The use of a convex lens to form an enlarged/magnified image
is discussed in Alhazen's Book of Optics (1021). Its
translation into Latin from Arabic in the 12th century was
instrumental to the invention of eyeglasses in 13th century
Italy. In a sermon delivered on February 23, 1306, the
Dominican friar Giordano da Pisa (ca. 1255–1311) wrote "It is
not yet twenty years since there was found the art of making
eyeglasses, which make for good vision”
The genesis of the
refractor telescope
A refractor telescope is composed of at least two lenses.
Lenses, whose name reflects their shape, have been known since Antiquity.
At that time they were mostly used for decoration, but the Ancients remarked
Giordano's colleague Friar Alessandro della Spina of Pisa (d. 1313) was soon
making eyeglasses. The Ancient Chronicle of the Dominican Monastery of St.
Catherine in Pisa records: "Eyeglasses, having first been made by someone else,
who was unwilling to share them, he [Spina] made them and shared them with
everyone with a cheerful and willing heart."
their peculiar properties.
Sénèque (4 BC- 65 AC) mentioned in his Naturales Quaestiones:
“Everything that is seen through water is bigger. The letters, though small
and pale, looks larger and clearer [when seen through] a sphere of glass
filled with water.”
One could also set paper on fire by using a small piece of polished glass.
Such observations and studies continued throughout the Middle Ages with
people like Alhazen, Grosseteste, and Bacon.
Detail of a portrait of the Dominican
Cardinal and renowned biblical
scholar Hugh of Saint-Cher painted
by Tommaso da Modena in 1352
The Glasses Apostle by Conrad von
Soest (1403)
Seated apostle holding lenses in position
for reading. Detail from Death of the Virgin,
by the Master of Heiligenkreuz, ca. 1430
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In 1538 the Italian scholar Girolamo Fracastoro
(c. 1478-1553) wrote:
“If someone looks through two eye-glasses, of which
one is placed above the other, he shall see everything
larger and more closely.”
The first description of a spyglass is to be found in a
letter from Giambattista della Porta, the Neapolitan
polymath, whose Magia Naturalis of 1589, well known
all over Europe, contained a tantalizing hint at what
might be accomplished by a combination of a convex
and concave lens:
”With a concave you shall see small things afar off,
very clearly; with a convex, things neerer to be
greater, but more obscurely: if you know how to fit
them both together, you shall see both things afar off,
and things neer hand, both greater and clearly.”
Who invented the
telescope?
Who invented the
telescope?
The history of the dissemination of the telescope starts in Middelburg,
with a letter of recommendation, dated 25 September 1608, in which
the authorities of the Dutch Province of Zeeland wrote as follows to
the States General, then the sovereign body of the young ‘Republic of
the Seven United Dutch Provinces’ in The Hague:
“The bearer of this letter declares to have [found] a certain art with
which one can see all things very far away as if they were nearby, by
means of sights of glasses, which he pretends to be a new invention”.
Who invented the
telescope?
“A few days before the departure of Ambrogio de Spinola [negotiator for the
Spanish sovereign] from The Hague a spectacle-maker from Middelburg, a
humble and God-fearing man, presented to His Excellency [Count Maurits],
Letter of recommendation for
Hans Lipperhey, written by
the ‘Gecommiteerde Raden’
of the province of Zeeland,
dated 25 September 1608.
certain glasses by means of which one can detect and see distinctly things
The archives of the States General confirm that Lipperhey received 300 guilders for
his device. The conditions stipulated that he would not make such a device for other
parties and he was requested to improve the instrument by making it suitable for two
eyes, and using rock crystal or glass of the very best quality for his lenses.
despite the fact that these cities are distant from The Hague one-and-a-
three or four miles removed from us as if we were seeing them from a
hundred paces. From the Tower in The Hague, one clearly sees, with the
said glasses the Clock of Delft and the windows of the Church of Leiden,
half, and three-and-a-half hours by road, respectively.”
Zoomers & Zuidervaart, Embassies
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Who invented the
telescope?
Who invented the
telescope?
In March 1609, the papal nuncius in Brussels, Guido Bentivoglio attended a
“The said glasses are very useful in sieges and similar
occasions, for from a mile or more away one can detect all
heron hunt organised for the archduke just outside the gates of that city, in
which one of these Brussels-made telescopes was tested. It amazed him how
‘miraculously’ the instrument performed, revealing details of a tower more than
things as distinctly as if they were very close to us. And even
ten miles away. Bentivoglio immediately ordered another copy to be made for
the stars which ordinarily are invisible to our sight and
Pope Paul V, which instrument arrived in Rome probably at the end of April
our eyes, because of their smallness and the weakness
of our sight, can be seen by means of this instrument.”
Zoomers & Zuidervaart, Embassies
1609. Another telescope was presented in May 1609 in Milan, brought there by
a Frenchman, who claimed to be an associate of the inventor from Holland.
This person was possibly the same as the ‘foreigner’ who at the end of July
1609 demonstrated a telescope in Padua, where lived Paolo Sarpi, a friend of
Galileo Galilei.
Who invented the
telescope?
After seeing or hearing of Lipperhey’s telescope, many scholars had a kind of
deja vu-feeling. Girolamo Sirtori, who in 1612, only four years after the
emergence of the instrument, composed his well-known Telescopium, captured
this feeling in the following phrase:
“It appeared that this conception was in the minds of many men, so that once
they heard about it, any ingenious person began trying to make one, without [the
help of ] a model.”
In the 1630s Sacharias Janssen’s son said that his father, who
was a spectacle maker in Middelburg, and a colleague and
Archduke Albertus of Austria, governor of the Southern Netherlands, observing a bird
competitor of Lipperhey, built his first telescope years before 1609,
with a telescope. Detail of a painting by Jan Brueghel the Elder, c. 1608-1611,
following an Italian device dated 1590. However there is no
representing the archduke in front of his castle Mariemont in Hanaut (Belgium).
documentary evidence confirming this.
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Who invented the
telescope?
Thus, within a year of the demonstration in The Hague, the telescope was
disseminated all over Europe, with the result that various European scholars
had already used or at least examined the instrument. Before the end of 1609,
telescopes were in the hands of Thomas Harriot in London, Galileo Galilei in
Padua,
Giovanbattista
della
Porta
in
Naples,
Simon
Marius
in
Gunzenhausen (Bavaria) and Rudolph Snellius in Leiden (Holland), to be
followed the next year by Johannes Kepler in Prague), Christoph Scheiner in
Ingolstadt (Bavaria), Nicolas Claude Fabri de Peiresc in Aix-en-Provence,
Willebrord Snellius and Johann Fabricius, both in Leiden, and Sir William
Lower in Carmarthenshire (Wales).
In a letter to the founder of the Accademia dei Lincei, Prince Federico Cesi in Rome,
dated 29 August 1609, Giambattista Della Porta made a sketch of an instrument
that had just reached him, and he wrote:
“About the secret of the spyglass [occhiale], I have seen it and it is a hoax
[coglionaria], and taken from the ninth book of my De refractione.. It is a small tube
of soldered silver, one palm in length, ad, and three fingerbreadths [diti] in diameter,
which has a convex glass in the end, a. There is another tube of the same [material],
4 fingerbreadths long, which enters into the first one, and in the end b it has a
concave [glass], which is secured like the first one. If observed with that first tube,
faraway things areseen as if they were near, but because the vision does not occur
along the perpendicular, they appear obscure and indistinct. When the other
concave tube, which produces the opposite effect, is inserted, things will be seen
clear and erect. And it goes in and out, as in a trombone, so that it adjusts to the
eyesight of [particular] observers, which all differ”.
Telescopes of Galileo
Galilean telescope
Characterized by the use of a negative (i.e., diverging) ocular (eyelens). In its simplest form,
comprises only two lenses: the objective lens, which is plano-convex or biconvex, and the ocular,
which is plano-concave or biconcave. The distance between the two lenses is equal to the
difference between the absolute values of their focal lengths, and the magnifying power is given by
the ratio of the focal lengths of the objective and the ocular. The advantage of the Galilean
telescope is that is provides an upright image without requiring an erector-lens system. Its
disadvantage is the extremely narrow field of view (moreover, in the Galilean design, the use of a
diaphragm on the objective reduces not only brightness but also the field of view); far from being
uniform, the brightness of the field of view gradually decreases from the center to the edge.
Another drawback that spelled its rapid abandonment by astronomers is the impossibility of fitting
the focal plane with a micrometer, i.e., a device for determining the angular size of the objects
observed.
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n ( ) 
c
v
Keplerian telescope
Characterized by the use of a positive (i.e., converging) ocular. In its simplest form, comprises
only two plano-convex or biconvex lenses, one serving as the objective, the other as the ocular.
To put it succinctly, the ocular functions as a magnifying lens that enlarges the (real) image
formed by the objective. The distance between the two lenses is equal to the sum of their focal
lengths, and the magnification is given by the ratio of the focal lengths of the objective and the
ocular. The astronomical telescope produces upside-down images. This drawback can be
eliminated by inserting an erector-lens system; it is largely offset by a somewhat broader and
uniformly brighter field of view than the one offered by the Galilean telescope. Unlike the latter,
the Keplerian design also allows the focal plane to be fitted with a micrometer, i.e., a device for
determining the angular size of the objects observed. The Keplerian telescope totally replaced
the Galilean model by the mid-seventeenth century. The instrument is also known as "Keplerian"
because its optical arrangement was first described by Johannes Kepler (1571-1630) in his
Dioptrice, published in Prague in 1611
All the telescopes used by Galileo are believed to have used plano-concave eyepieces. When
such a lens is placed inside the prime focus by its own focal length, f, the effect is as shown:
OTTICA
PERFETTA
Aberrazione
cromatica
Aberrazione
sferica
Astigmatismo
The following diagram illustrates the effect of using a positive eye lens with identical focal length
and diameter to that in the previous example:
Cromatica + sferica +
astigmatismo
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John Dollond
The large images was photographed with the positive eyepiece. A 16 mm diameter baffle close
to the prime focus limits the field to 55 arc minutes. The small images shows, to the same scale,
the small portion of the Keplerian view visible at any one time with a negative eyepiece of the
same focal length. The full diameter of the Galilean field, which is unaffected by the baffle, is 14
arc minutes.
Left: A reference picture of the insulator
on the phone pole taken with the
Celestron C8 and reduced to the scale
of the Galilean photos. Center: Detail
from the center of a Galilean
photograph showing the same insulator
as seen through the 23 mm refractor
with its negative eyepiece. Right:
The Celestron and positive eyepiece images have Detail from the center of photograph
been inverted and rotated to match the Galilean view.
taken with the positive eyepiece using
the same camera settings.
The primary limitation of the image quality that was produced with early telescopes
was chromatic aberration of the objective lens. Because of the color dispersion of
the glass in a simple objective lens, different wavelengths have different focal
lengths and are brought to focus at different distances.
Achromatic objectives correct chromatic aberration by combining a positive lens
made from a low-dispersion glass with a negative lens made from a high-dispersion
glass. The original inventor of the achromatic objective is Chester Moor. In 1733
he commissioned two different opticians, Edward Scarlett and James Mann, to
each make one of the lens elements. By chance, both opticians subcontracted the
work to the same man, George Bass. Chester Moor Hall then continued to keep his
invention secret. Around 1750, Bass told optician John Dollond about the
achromatic lens he had made. Dollond’s son, Peter, saw the commercial
advantages and once they had made test lenses, patented the invention in 1758.
Chester Moor Hall twice attempted to challenge the patent.
Dollond Telescope with Tripod
Signature
Date
Dimensions
Main Tube Length
Main Tube Diameter
Total Length
Closed Length
Objective Clear Aperture Diameter
Dollond, London
Circa 1800
Metric
265mm
56mm
1055mm
195mm
52mm
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Joseph von Fraunhofer
“I stood astonished before this beautiful instrument, undetermined which to
admire most, the beauty and elegance of the workmanship in its minute parts,
the propriety of its construction, the ingenious mechanism for moving it, or the
incomparable optical power of the telescope and the precision with which objects
are defined……What a difference is seen there! A mountain peak illuminated on
the dark side of the Moon, which offers me noting remarkable in the Troughton
(refractor), I recognize, by means of the Giant Refractor as consisting of 6 peaks
well separated from each other. One of the most difficult of Herschel’s double
stars I recognize immediately. I believe this telescope can be boldly placed
alongside the giant reflecting telescope of a Herschel, for if the latter has a
greater light-gathering power, our achromat surpasses by far any reflecting
telescope in the precision of the images (…) By clockwork the telescope can
be given a uniform motion similar to the velocity of the fixed stars, so that the
star remains in the field of view.”
Percival Lowell
F.G. Wilhelm Struve
The 77-centimetre (30 in) refractor at Nice Observatory, when built the world's largest, longest, and highest refracting telescope
On the night of January 31st, 1862, Alvan Clark and his son,
Alvan Graham Clark, were testing a lens for a new telescope18and-a-half inches in diameter. To test it, the Clarks turned it
toward Sirius, the brightest star in the night sky. Within
moments, the younger Clark discovered that the star had a
companion — a dot so faint and so close to Sirius itself that
it had never been seen through the star’s glare.
The companion had been predicted by German astronomer
Friedrich Bessel who noticed small odd irregularities in the
proper motions of the star.
The 65 cm Zeiss (25.59 inches) achromatic refractor of Pulkovo observatory. The 30 inch (76 cm)
refractor on the right, installed in 1885, was one of the largest telescopes in the world at that time
The success of Clark’s lenses was attributed to skilful manipulation and supervision rather than the use of precise
mechanisms. Clarks regularly retouched all four surfaces of each objective.
This maybe the explanation for the superior quality of the Clarks object glasses.
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D=100mm
Diffraction limit to resolution of two
point-object images in incoherent light
is approached when the two are of
D=30mm
near equal, optimum intensity. As the
two PSF merge closer, the intensity
deep between them diminishes. At the
center separation of half the Airy disc
diameter - 1.22λ/D radians (138/D in
arc seconds, for λ=0.55μ and the
aperture diameter D in mm), known
as Rayleigh limit - the deep is at
nearly 3/4 of the peak intensity.
This refractor is still the largest
in the world today.
The combined weight of the two
components of the 40-inch
objective was 225 kg
“From these tests it appears that the character of the image varies with the position of the lenses relative to each
other, and, to a less extent, with the position of the objective as a whole relatively to its cell. It is probable that flexure
of the lenses is the principal cause of the observed changes, and it is interesting to note that there is here evidence, for
the first time, that we are approaching the limit of size in the construction of great objectives”.
James Edward Keeler - 1896
Takahashi FET-200 Fluorite ED
Triplet on EM-3500 Mount
$165,480.00
Takahashi FSQ-130ED Super APO
$12,795.00
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In 1856-57, Karl August von Steinheil and Léon Foucault introduced a process of
depositing a layer of silver on glass telescope mirrors. The silver layer was not only
much more reflective and longer lasting than the finish on speculum mirrors, it had
the advantage of being able to be removed and re-deposited without changing the
shape of the glass substrate. Towards the end of the 19th century very large silver
on glass mirror reflecting telescopes were built.
The beginning of the 20th century saw construction of the first of the "modern" large
research reflectors, designed for precision photographic imaging such as the 60inch Hale telescope of 1908, and the 100-inch (2.5 m) Hooker telescope in
1917. 1948 saw the completion of the 200-inch (510 cm) Hale reflector at Mount
Giornale di Fisica. Chimica e storia naturale ossia Raccolte di Memorie sulle Scienze, Arti e Manifatture ad esse
relative di Luigi Brugnatelli. - Pavia, Tipogr. Capelli 1808-1827
Palomar which was the largest telescope in the world
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Galileoscope (+ webcam) in action – Moon and Planets
Galileoscope in action – M45, The Pleiades
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Bibliography
•
Chapman A., A new perceived reality – Thomas Harriot’s Moon maps, Astronomy & Geophysics, vol 50, p1.27 (2009)
•
King H.C., History of telescope, 1955, Sky Publishing Corp.
•
Rosen E., Did Galileo claim he invented the telescope ?, Proceedings of the American Philosophical Society, vol 98, p304 (1954)
•
Rosen E., The invention of eyeglasses, Journal of the History of Medicine, vol 11, p13 & p183 (1956)
•
Van Helden A., The invention of the telescope, Transactions of the American Philosophical Society, vol 67, #4 (1977)
•
Wilson R., Reflecting Telescope Optics I & II, 1996 & 1999, Springer
•
V. Greco, G. Molesini, and F. Quercioli, "Optical tests of Galileo's lenses," Nature (London) 358, 101 (1992).
•
V. Greco, G. Molesini, and F. Quercioli, "Telescopes of Galileo," Applied Optics 32, 6219-6226 (1993).
•
G. Molesini, "The Telescopes of Seventeenth Century Italy," Optics & Photonics News (June 2003) 35-39.
•
The History of Telescopes and Binoculars: An Engineering Perspective - John E. Greivenkamp∗ and David L. Steed
•
Galilean Telescope Homepage
•
History of the telescope
•
Museo Galileo http://catalogue.museogalileo.it/index.html
1609
Galileoscope in action – M42, The Great Orion Nebula
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