David Gill

by catcher Monday, July 23, 2012 10:51 AM

'The Surveyor'


Born: 12th June 1843, Aberdeen, Scotland
Died: 24th January 1914, Kensington, London, England

Sir David Gill was one of the great astronomers of the late nineteenth century, and was universally recognized as such. He made significant contributions to many areas of astronomy, including the measurement of the sun’s distance and the completion of a successful photographic survey of stars in the southern hemisphere, known as the Cape Photographic Durchmusterung or CPD, which listed the positions and magnitudes for 454,875 stars down to about magnitude 10.2 in the Southern Hemisphere.

David Gill was a surveyor not of buildings or land but of the heavens.
Although originally destined to become a clock maker like his father, fate chose otherwise. Ironically it was through clocks that

David Gill became interested in Astronomy, a hobby which would eventually lead to a career that lasted fifty years, during which time he was to become one of the great astronomers of his age.

All throughout his astronomical career David Gill was involved in measuring and surveying.

At first it was a desire to set up an accurate time service for his native city of Aberdeen. Then he began to make plans to measure the distance of nearby stars. This was followed shortly by an expedition to Ascension Island to determine the distance of the planet Mars and by implication the distance of the Sun from the Earth.

However it was his great photographic survey of the stars in the southern hemisphere – the ‘Cape Photographic Durchmusterung’ that became his greatest legacy to Astrophotography and Astronomy in general.

To read more on his life and work read the eBook chapter on David Gill or buy the Book 'Catchers of the Light'.

9-inch CPD 'Photographic Refractor', Cape of Good Hope Observatory, c1886

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Pioneers of Astrophotography

Ernest Amedee Barthelemy Mouchez

by catcher Monday, July 23, 2012 10:31 AM

'The Visionary Man'

Born: 24th August 1821, Madrid, Spain
Died: 29th June 1892, Wissous, Seine et Oise, France

Rear Admiral Ernest Amedee Barthélémy Mouchez was a man of vision who recognized the role of photography as an important tool to chart the heavens. To this end he instigated the ill fated and over ambitious Carte du Ciel project. His faith in the Carte du Ciel was ultimately rewarded when data from the project was successfully used in conjunction with that obtained from the HIPPARCOS Astrometric Satellite.

“Gentlemen: In the name of the Paris Observatory I also welcome the eminent men of science who have graciously accepted our invitation to this international congress, where will be decided the execution of a work of the first importance for the future of astronomy.

I tender my profound thanks for the cordial readiness with which you consented to come at our call, which proves the great interest you all feel in this new branch of science, astronomical photography, which, by your recent labours, has made such admirable and rapid progress.

It has now become a wonderful and potent auxiliary, the great value of which one could not overestimate. By its aid—since a document can be secured in an hour’s time for which a year’s work would have been required by the old methods— the slow and laborious processes of astronomical observations will be changed. There will, perhaps, be some weak resistance, some obscure regret, as is inevitably produced by every great progress, but which will soon vanish before the brilliant light of success, as a half-century ago the old stage-coaches disappeared before the triumph of the locomotive.

It is, therefore, a great honour for our old national observatory, in the course of the progresses it also has realized, to receive the first assembly, where this (for astronomical science) new era is about to be inaugurated.

It will be a glorious and never-to-be-forgotten date in its history, as will be likewise memorable the grand work which we wish to leave as a legacy to future generations—a work which we might define as an inventory, as exact and as complete as possible, of the visible universe at the close of the nineteenth century.


Le Contre-Amiral, Directeur de l’Observatoire”

The above words were spoken by Ernest Amedee Barthélémy Mouchez (1821–1892) at the opening of the ‘Congres Astrophotographique’ held in Paris from the 16th to the 25th of April 1887.

His vision of a Carte du Ciel (literally - Map of the Sky) never came true in his lifetime. History has written a different ending to that predicted by Ernest Mouchez – one of problems, delays, acrimony, over ambition, failure and ultimate redemption.

Whatever is written of Ernest Mouchez concerning the Carte du Ciel, nobody can deny that he was a Visionary; who tried to do something that at the time was impossible from the outset, but which today is taken for granted – a Complete Photographic Chart of the Heavens.

To read more on his life and work read the eBook chapter on Ernest Amedee Barthelemy Mouchez or buy the Book 'Catchers of the Light'.


Dome of the Paris Observatory's 'Carte du Ciel' Astrograph Today: Photograph courtesy of the Paris Observatory Museum

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Pioneers of Astrophotography

Julius Scheiner

by catcher Monday, July 23, 2012 1:01 AM

'The Rainbow Man'

Born: 25th November 1858, Cologne, Germany
Died: 20th December 1913, Potsdam, Germany

Julius Scheiner was the first astronomer to proved conclusively through photographic spectroscopy that the ‘Great Andromeda Nebula’ was in fact an ‘Island Universe’ made up of individual stars. Together with Hermann Carl Vogel, the Director of the Potsdam Astrophysical Observatory and its Hauptobservator, Wilhelm Oswald Lohse, the three became 'The Rainbow Men' of Astrophysics, renowned for their great work in the 'New Astronomy' of Astrophysics.

It is now known that the ‘Great Andromeda Nebula’ (M31) is a great star system or Galaxy similar to our own Milky Way, but lying at a distance of over 2.5 million light years away. However during the nineteenth century and indeed into the first twenty years of the next, astronomers were uncertain as to its true nature or its distance. Was it made of stars or gas? And was it part of our Milky Way or did it lie outside its boundaries? Nobody was sure.

In 1899 Scheiner took a photograph of the complete spectra of the ‘Great Andromeda’ nebula, M31, which clearly showed it to be made up of individual stars, thus confirming the earlier visual work of William Huggins.

To read more on his life and work read the eBook chapter on Julius Scheiner or buy the Book 'Catchers of the Light'.

The 'Great Andromeda Spiral' (M31), George Willis Ritchey, 24-inch reflector, 1901

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Pioneers of Astrophotography

Edward Charles Pickering

by catcher Monday, July 23, 2012 12:11 AM

'The Ladies' Man'

Born: 19th July 1846, Boston, Suffolk, Massachusetts, USA
Died: 3rd February 1919, Cambridge, Middlesex, Massachusetts, USA

Edward Charles Pickering had three great talents; one was the ability to inspire himself to do great things; the second to recognize the potential in women, to become great astronomers; and lastly to persuade wealthy philanthropists to part with their money to finance his research. With these talents and the women he employed, some of the finest astronomical research ever carried out, was done under his supervision at Harvard College Observatory during the forty two years he was its Director.

Edward Charles Pickering (1846-1919) was one of the new breed of Astronomers that began to appear in the USA during the last decades of the nineteenth century. Unlike many of his European counterparts, he was not interested in the old Astronomy of measurement and position. He did not want to know where a star was in the sky; but to know the answers to more ‘important’ questions like: how bright it was; why were some stars intrinsically brighter or dimmer than others; and why some stars were orange and others were white.

He was above all else an Astrophysicist who wanted to use the science of physics to understand the stars. Throughout his career he used photography in an attempt to answer the many questions that burned in him - like the stars he wanted to understand. During his time as Director of the Harvard College Observatory which lasted longer than any other that have held this illustrious office, he and his female staff of Astronomers carried out fundamental Astrophysical research into the measurement of stellar magnitudes, the classification of stellar spectra and the size of the Universe itself.

With his great personal charm Edward Charles Pickering had the knack of obtaining grants of large sums of money to pursue his research and in particular to construct some of the finest examples of Photographic Refractors (Astrographs), notably the 8-inch Bache and 24-inch Bruce Telescopes.

To read more on his life and work read the eBook chapter on Edward Charles Pickering or buy the Book 'Catchers of the Light'.

8-inch 'Bache Astrograph': Photograph courtesy of Harvard College Observatory Archives

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Pioneers of Astrophotography

William Huggins & Margaret Lindsay Murray

by catcher Sunday, July 22, 2012 11:49 PM

‘The Devoted Couple’

William Huggins
Born: 7th February 1824, Cornhill, London, England
Died: 12th May 1910; Brixton, London, England

Lady Margaret Lindsay Murray
Born: 14th August 1848, Dublin, Ireland
Died: 24th March 1915, Chelsea, Middlesex, England

Sir William Huggins was a one of the founders of modern Astrophysics. He and his wife Margaret Lindsay Murray conducted some of the earliest research into the spectra of stars, and contributed greatly to our knowledge of the physical structure of the universe based on a common set of chemical elements.

For the very first time man began to glimpse the sheer size of what he saw when he looked up at the night sky from the Earth; a planet which he now realized was nothing more than a speck of dust in the cosmic scheme of things.

How must Friedrich Wilhelm Bessel (1784-1846) have felt in 1838 when he calculated the distance to the star 61 Cygni to be an incredible 10.4 light years away – or to put it in terrestrial distances, a staggering 98,391,159,596,914,840.32 km? , which is the equivalent of travelling 2,455,175,535,793 times round the Earth’s Equator in a plane! Such distances are in truth beyond our comprehension.

Tremendous though the achievement of Bessel was, it was only the beginning. At that time nobody had any idea of what a star really was, or what it was made up of; and they certainly knew even less about the many objects known as ‘nebulae’ which astronomers were beginning to find in ever increasing numbers as faint ‘smudges’ in the eyepieces of their telescopes.

All of this was about to change in the early 1800s with the birth of the new branch of Astronomy known as Astrophysics; which was concerned, not with position and measurement of the old days, but with the very make up and workings of the universe itself. The customers who patronized the London premises of William Thomas Huggins, silk mercer and linen draper, during the middle years of the nineteenth century, may well have been served by his young son William Huggins (1824-1910); little knowing that they had met someone who would soon begin to add pieces to a jigsaw puzzle, which when complete would explain the very nature of the universe in which they shopped.

In the years following the publication of his first scientific paper in 1856, Sir William Huggins, as he was later to become, carried out some of the very earliest investigations into Astronomical Spectroscopy in which he hoped to ‘discover whether the same chemical elements as those of our earth are present throughout the universe…’ At the time of his death in 1910 he was in a position to write that it ‘was most satisfactorily settled in the affirmative; a common chemistry, it was shown, exists throughout the universe.’

It has been said that Sir William Huggins was the ‘Father of Astronomical Spectroscopy’, but if this so then his wife Lady Margaret Lindsay Murray (1848-1915) was its mother. In the years following their marriage in 1875, she was not only his wife, but a friend, an assistant, a photographer and a co-worker. It was Margaret Lindsay Murray who introduced photography as an integral and necessary element of their 35 years of devotion to each other and to their work.

To read more on their lives and work read the eBook chapter on William Huggins & Margaret Lindsay Murray or buy the Book 'Catchers of the Light'.

Photographic Spectra of Bright Stars, Sir William Huggins & Lady Margaret Huggins

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Pioneers of Astrophotography

Pietro Angelo Secchi

by catcher Sunday, July 22, 2012 11:34 PM

'God's Astronomer'

Born: 29th June 1818, Reggio Emilia, Emilia-Romagna, Italy
Died: 26th February 1878, Rome, Lazio, Italy

Father Pietro Angelo Secchi was a Jesuit Priest and a pioneer of astronomical spectroscopy. The work for which he is best remembered is his Spectral Classification System; which ultimately led to the Harvard Classification of Stellar Spectra developed by Williamina Fleming, Antonia Maury and Annie Jump Cannon in the 1890s and early 1900s.

The Roman Catholic Church has always kept a close eye on the heavens, but even more so, on the astronomers who studied it:

“I, Galileo, being in my seventieth year, being a prisoner and on my knees, and before your Eminences, having before my eyes the Holy Gospel, which I touch with my hands, abjure, curse, and detest the error and the heresy of the movement of the earth.”

In these words the Italian astronomer Galileo Galilei (1564-1642) had recanted his belief that the Earth revolved around the Sun, and that the Earth was indeed the centre of the Kingdom of Heaven. It was the year 1633 and nothing could move the Catholic Church away from the view that God’s Universe was perfect and without flaws. The Earth did not move; there were no spots on the surface of the Sun or craters on the Moon; and almost certainly no dark lines could be seen emanating from the stars. Galileo renouncing what he knew to be true in his heart, was exiled to his villa at Arcetri near Florence in 1634, where he spent the remainder of his life under house arrest.

In 1818 there was born a man who in later life would see all of these things, including the dark absorption lines in the spectra of stars. What is remarkable is that his name was Father Pietro Angelo Secchi, a Jesuit Priest; and firm believer in both his church, and a heaven based on science, not on what his religion wanted it to be.

In 1877 Secchi published the results of his great study of 4000 fixed stars, in which he argued that all stars could be classified according their chemical nature as exhibited by the various dark absorption lines found in their spectra. Furthermore this classification could be achieved by using only five spectral types. These later became known as ‘Secchi Classes’.

The pioneering work of Secchi in the Spectral Classification of Stars, ultimately led to the Harvard Observatory’s Classification as developed by Williamina Fleming, Antonia Maury and Annie Jump Cannon in the 1890s and early 1900s. This in turn formed the basis of the currently accepted Morgan-Keenan system.

The accurate classification of stars according to the characteristics of their spectra was the start needed by others to begin the process of understanding their structure and evolution, from the moment of their birth amongst vast clouds of gas and dust, to an end which produces white dwarfs, neutron stars and black holes - bodies as strange as they are unbelievable.

Father Secchi lived a contented life within the embrace of his venerated Catholic Church and his beloved Pope, but at the same time conducting astronomical research into the very nature of a ‘flawed’ universe. Yet two centuries earlier this very same research would have condemned him to exile or even death.

How could this be? How did Pietro Angelo Secchi on his death in 1878 enter the ‘Kingdom of Heaven’ with the full blessing of the Holy Catholic Church, as both Jesuit and Astronomer?

To read more on his life and work read the eBook chapter on Pietro Angelo Secchi or buy the Book 'Catchers of the Light'.

Pietro Angelo Secchi's, Spectroscope, c1866

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Pioneers of Astrophotography

Edward Emerson Barnard

by catcher Sunday, July 22, 2012 10:34 PM

'The Photographer's Assistant'


Born: 16th December 1857, Nashville, Tennessee, USA
Died: 6th February 1923, Williams Bay, Wisconsin, USA

Edward Emerson Barnard was one of the greatest observational astronomers of all time. Despite having virtually no formal education, his enthusiasm and his knowledge of the night sky enabled him to become a staff astronomer at both the Lick and Yerkes Observatories. It was from these ‘Great’ Observatories that he took some of the finest ‘wide field’ images ever captured of our universe.

Edward Emerson Barnard (1857-1923) had an inauspicious start to life. He was brought up in the ‘Deep South’ of the United States, amid the poverty, disease and death of the American Civil War. His father had died before he was born and from an early age he needed to work to support his family, thus sacrificing even the slim chance he might have had of receiving any form of uninterrupted education whatsoever. Yet despite all of this he grew up to become one of the greatest astronomers of his age and the earliest pioneer of ‘wide field’ Astrophotography.

It was not surprising that the young Barnard developed a high degree of self reliance, a great capacity for hard work and a tenacity to persevere no matter what life had to throw at him. Before he was even nine years, he had begun work as a photographer’s assistant, and for the next seventeen years he remained with the same photographic studio learning the business of photography; a trade which was to prove invaluable in later life, when he turned his attention to imaging the heavens. 

As a young boy he acquired a great interest in astronomy long before he had ever owned or even used a telescope. He was often to be found after dark , lying on his back in an old wagon looking up at the stars.  On summer evenings he later recalled, after dusk had fallen, a bright white star shone high above his home. It was a sight which fascinated him and for some unknown reason it always remained his special star. He never forgot this star, only years later did he learn that it was called Vega.

In 1881, Barnard discovered the first of the sixteen comets that now bear his name, a number greater than that of the legendary French ‘comet ferret’ Charles Messier, who could only manage a measly thirteen. His Comet discoveries gained him attention of the astronomical community, who would now remember his name both during his lifetime and in the decades which followed; even today day he is still revered amongst amateur and professional astronomers alike.

In his professional career which lasted forty years from his first appointment at Nashville’s Vanderbilt University Observatory in 1883, until his death in 1923 at the Yerkes Observatory, Wisconsin, E. E. Barnard never forgot his astronomical roots. For it was the thrill of comets and the wonders of the Milky Way which were to become the ‘targets’ for the magnificent images which even now over a century later are only rarely bettered.

To read more on his life and work read the eBook chapter on Edward Emerson Barnard or buy the Book 'Catchers of the Light'.


The 'North American' Nebula (NGC 7000) in Cygnus, Edward Emerson Barnard, 1905

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Pioneers of Astrophotography

James Edward Keeler

by catcher Sunday, July 22, 2012 10:16 PM

'The Mirror Man'


Born: 10th September 1857; La Salle, Illinois, USA
Died: 12th August 1900; San Francisco, California, USA

During the latter part of his career James Edward Keeler used the 36-inch 'Crossley' Reflector at the Lick Observatory, California, USA to demonstrate the great potential large silvered mirrored reflectors had in the conduct of astrophysical research. The wonderful images produced by James Edward Keeler with this telescope are a great testament to his all too brief life.

James Edward Keeler (1857-1901) was one of the first professional astronomers to recognize the great contribution large silvered mirrored reflecting telescopes could make in man’s never ending quest to understand the nature, structure and origin of the universe, in which he is just a mere speck of dust in the enormity that surrounds him.

Astronomy in the nineteenth century was dominated by the refractor. It was the age when the great observatories of the world competed to own the telescope with the largest objective lens. In 1847 the largest refractor had an aperture of just 15-inches, with the observatories at Harvard College, in Cambridge, Massachusetts and the Imperial Russian Observatory at Pulkovo, near St. Petersburg each owning instruments that jointly held the then title of world’s biggest telescope.

The years that followed saw refractors of ever increasing size being constructed, with no observatory holding the title of ‘world’s largest’ for more than a few years at a time. By the end of the century there were six refractors with apertures of 30-inches or more: the 30-inch at Pulkovo (1885); the 30.3-inch at Nice (1886); the 31.5-inch at Potsdam (1899); the 32.7-inch at Meudon (1891); the 36-inch at Lick (1888); and the 40-inch at Yerkes (1897. Of these ‘Great Refractors’ only those at Pulkovo, Nice and Lick were briefly entitled to call itself the ‘world’s largest’; the two at Meudon and Potsdam never could.

Even the massive 40-inch at Yerkes briefly lost its seemingly ‘permanent’ crown in 1900, to the ill-fated 49.2-inch ‘Paris Exhibition’ telescope.

Unbeknown to the astronomical establishment of the time an alternative type of telescope - which they had  completely ignored and frequently scorned, was preparing to hammer the ‘nails into the coffins’ of the precious but ageing dinosaurs which were their ‘Great Refractors’. These once fine instruments had dominated the world of astronomy for nearly three centuries, ever since the time of Galileo, but were now reluctant to move into a new world born of photography and one to be dominated by a new species of telescopes.

The alternative in question was the silvered mirrored reflecting telescope, which for the whole of the nineteenth century was largely left in the hands of a dedicated but nevertheless competent body of amateur astronomers. Even James Edward Keeler who was to become one of the reflector’s greatest supporters was until the last few years of his life totally ignorant of the capabilities of such telescopes.

In 1898, Keeler was appointed the Director of the Lick Observatory atop Mount Hamilton in California, with it came a telescope which was unknown, untried and mistrusted – a 36-inch silvered mirrored reflector, the gift of a carpet tycoon from Halifax, England, named Edward Crossley. In the two years which were left to him, James Edward Keeler, learnt to trust his new charge, to repair and modify it, and in doing so turned what was a ‘Trojan Horse’ into the beginnings of a new age - the era of the reflector.

With the 36-inch ‘Crossley’ reflector, James Edward Keeler and his assistant Charles Dillon Perrine (1867-1951) took a series of photographs of Deep Space Objects (DSOs), which even in the age of the CCD chip are still arguably some of the finest ever taken.

To read more on his life and work read the eBook chapter on James Edward Keeler or buy the Book 'Catchers of the Light'.


The 'Lagoon' Nebula in Sagittarius, James Edward Keeler, 36-inch reflector, 1899

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Pioneers of Astrophotography

Pierre Paul Henry & Mathieu Prosper Henry

by catcher Sunday, July 22, 2012 8:13 AM

'The Inseparable Brothers'

Pierre Paul Henry
Born: 21st August 1848, Nancy, Meurthe-et-Moselle, Lorraine, France
Died: 4th January 1905, Montrouge, Paris, France

Mathieu Prosper Henry
Born: 10th December 1849, Nancy, Meurthe-et-Moselle, Lorraine, France
Died: 25th July 1903; Pralognan, Rhône-Alpes, France

The Henry Brothers – Pierre Paul and Mathieu Prosper, were inseparable all throughout their lives. Together they grew up to be two of the greatest Astrophotographers of all time and were the first to take truly successful photographs of the Planets. They also created some of the finest telescopes ever made, which were without doubt the equal of those of the legendary Alvan Clark & Sons. Their pioneering experiments in using photography to create star charts was a major contributory factor in persuading Amedee Mouchez to inaugurate the ill fated ‘Carte du Ciel’ project.

Pierre Paul Henry (1848-1905) and his younger brother Mathieu Prosper Henry (1849-1903), lived in the world as though they were just a single person. Everything they did in life, they did together; they went to the same school, they both trained as opticians, they both left to live in Paris, they both became astronomers and both got jobs at the Paris Observatory – where they both worked together.

Pierre Jean Octave Callandreau (1852–1904), a colleague of theirs at the Paris Observatory wrote of them:

“So united was their friendship and collaboration that at the Observatory we seemed to see but one person; so forgetful were they of giving prominence to their respective merits that it is impossible to decide what may belong to each of their common work.”

Together their achievements made them famous the world over, and in France they could do no wrong:

  • They took the first successful photographs of the Planets when they imaged Jupiter and Saturn in 1886;
  • They provided the optics for the first example of Maurice Loewy’s (1833-1907) Equatorial Coude Refractor - a new and radical telescope design;
  • They took magnificent photographs of stars down to the below the 15th magnitude, which convinced the Observatory’s Director Contre-Amiral Amedee Ernest Barthelemy Mouchez (1821-1892) that a complete photographic survey of the heavens was technically possible;
  • At the end of their lives they constructed with the Parisian engineer Paul Gautier (1842-1909) large refracting telescopes for the Nice and Meudon Observatories, which rivaled those built by Alvan Clark & Sons of Cambridge, Massachusetts, USA.

It was a team of one that the inseparable brothers became two of the truly great pioneers of Astrophotography.

To read more on their life and work read the eBook chapter on Paul Henry & Prosper Henry or buy the Book 'Catchers of the Light'.

'La Grande Lunette de Meudon', Double Refractor (32.7/24.4-inch), Henry Brothers: Photograph courtesy of the Paris Observatory

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Pioneers of Astrophotography

Pierre Jules Cesar Janssen

by catcher Sunday, July 22, 2012 7:59 AM

'The Elemental Man'

Born: 22nd February 1824, Paris, France
Died: 23rd December 1907, Meudon, France

Pierre Jules Cesar Janssen used photography to study the Sun and was therefore one of the founders of Solar Physics. In 1868, during an expedition to India to witness a Total Eclipse of the Sun, Janssen noticed the presence of an unknown line in the yellow part of the solar spectrum at a wavelength of 587.4 nm; which was later found to be produced by a new and as yet undiscovered element – now known as Helium. This was the first chemical element to be discovered on another world.

In an episode of the well known American cartoon series, the Simpsons, Principal Skinner, the head of Springfield School is seen to raise his fist and utter the words: “Curse the man who invented helium! Curse Pierre Jules César Janssen!”.

In 1868, over a hundred and thirty years earlier, the French scientist and astronomer, Pierre Jules Cesar Janssen (1824-1907) had travelled to India to witness a Total Eclipse of the Sun, which was due to take place on the 18th of August that year. During the expedition he noticed the presence of an unknown line in the yellow part of the solar spectrum having a wavelength of 587.4 nm, which was totally unfamiliar to him:

“The bright yellow line was actually located very close to D [sodium], but it belonged to refrangible rays more than D. My subsequent studies on the Sun show the accuracy of what I say here.”

However, the line was also noticed on the 20th October 1868 by the eminent English scientist, Sir Joseph Norman Lockyer (1836-1920) who in 1870 concluded that this was due to an unknown chemical element, which was  later to become known as helium after the Greek God of the Sun – Helios.

This was a momentous observation as it led to discovery of the very first chemical element to be found on another world. Although, Janssen’s observation of the chemical element Helium made him famous, it was not the only significant contribution he made to science.

In 1862 Janssen had established an observatory in the Montmartre district of Paris, where he carried out investigations into the Solar Spectrum. He believed that some of the dark absorption lines in its spectrum did not emanate from the Sun itself, but were caused by the earth’s atmosphere. These became known as the Telluric Lines, a name given to them by Janssen.

On the 19th of August 1868, a day after the total eclipse, Janssen made a discovery which had a major impact on Solar Physics. He found a method of utilizing the Fraunhofer ‘C’ Emission Line, also known as ‘Hydrogen Alpha’ by which he could observe the spectra of Solar Prominences without the need for a Total Solar Eclipse. The same method was independently discovered somewhat later by his friend, Lockyer. The French Academy of Sciences struck a medal bearing the effigies of the two scientists to commemorate the achievement.  A ‘Hydrogen Alpha’ filter is still used today by the modern day Astrophotographer to obtain images of the Sun’s surface, its prominences and flares. For this we have to thank Janssen and Lockyer.

In 1874 Janssen went to Japan to observe the transit of Venus, and in order to witness the exact moment of the planet’s contact with the sun’s limb, he had developed a special camera he called the ‘Revolver Photographique’. This remarkable instrument was able to take a rapid series of photographs with very short exposures showing Venus’s approach towards the limb of the sun. It was the very first webcam!

However, it was his ‘L’Atlas de Photographies Solaires’, published in 1904, which earned Jules Pierre Cesar Janssen his right to be called one of the great pioneers of Astrophotography and one of the founders of modern Solar Physics. This remarkable work contains some 6,000 photographs of the Sun taken in the years 1876 to 1903 from the newly established Meudon Observatory, near Paris; which was later to be known as the Paris Astrophysical Observatory.

To read more on his life and work read the eBook chapter on Pierre Jules Cesar Janssen or buy the Book 'Catchers of the Light'.

The Solar Surface, from L'Atlas Photographiques Solaires, Jules Janssen

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Pioneers of Astrophotography

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Stefan Hughes began his career as a professional astronomer, gaining a 1st Class Honours degree in Astronomy from the University of Leicester in 1974 and his PhD four years later on the 'Resonance Orbits of Artificial Satellites due to Lunisolar Perturbations', which was published as a series of papers in the Proceedings of the Royal Society of London. After graduating he became a Research fellow in Astronomy, followed by a spell as a lecturer in Applied Mathematics at Queen Mary College, London. Then came a ten year long career as an IT Consultant. In 'mid life' he spent several years retraining as a Genealogist, Record Agent and Architectural Historian, which he practiced for a number of years before moving to the Mediterranean island of Cyprus, where for the past ten years he has been imaging the heavens, as well as researching and writing the 'Catchers of the Light' - A History of Astrophotography.