Astronomer and mathematician who calculated as a first one the Sun parallax and the distance between the Earth and the Sun. A 1970 Czechoslovakian stamp honors this German astronomer, dressed as a Laplander. It was there that he was first to observe a transit of Venus. He was director of the astronomy observatory in Vienna, even after the Suppression of the Jesuits. A lunar crater is named after him. Maximilian Hell, S.J. died 200 years ago in 1792, after falling victim to the defamation of Jesuits during the Suppression of the Society. Accused of altering his data during the 1769 transit of Venus, he was not exonerateed until a century later when the renowned American astronomer Simon Newcomb found Hell's readings to be correct, his scholarship above suspicion and his accusers guilty of slander. The damage done his reputation, however, survived him because of historians who failed to report his rehabilitation.

Because of his personal qualities as well as his scientific adventures Hell was held in high esteem by all who knew him. He was elected to the most prestigious scientific academies of Europe. The rulers of both England and Denmark offered him large honorary pensions which he modestly declined. At the urging of fellow scientists he attempted to form an imperial academy of science, but was thwarted by political enemies of the Jesuits. He did succeed in publishing a very timely and indispensable journal concerning the latest scientific discoveries. A lunar crater is named after Hell and a 1970 Czechoslovakian stamp honors him dressed as a Laplander recalling his famous scientific expedition.

Maximilian Hell was born into a family of engineers in 1720 in the city of Selmecz (Schemnitz), Hungary. His father was the chief engineer of the local mines and his brother invented an ingenious machine to pump water out of the mine shafts. After joining the Jesuits Maximilian taught mathematics, astronomy, physics and technology and attracted large numbers to his celebrated lectures. He also was a prodigious writer having no less than 35 entries in Sommervogel's Bibliography and requiring 20 pages of narration. Both his teaching and writings promoted a popular understanding and enthusiasm for astronomy, spreading Hell's reputation throughout Europe.

Among his adventures were experiments in magnetism applied to medicine. This was unchartered ground. By assuming very unconventional premises he started something quite remarkable. Using lodestone he devised an arrangement of magnetic plates for the lessening of pain from diseases, including attacks of rheumatism from which he himself suffered. He met with considerable success in relieving the pain. His magnetic medicine attracted the attention of a young man named Franz Mesmer, recently graduated from the Jesuit University of Dillingen in Bavaria. Mesmer disregarded the magnets and developed a different, but even more peculiar theory of healing based on circulating cosmic fluids in the body. The hypothesis of both men were found to be groundless but eventually investigators of these phenomena made mesmerism, or hypnotism, an accepted medical practice.

The story of Hell's detractors can be found in the Dictionary of Scientific Biography, in ISIS and in the modern histories of astronomy. Just before the Suppression, Jesuits directed 30 of the world's 130 major astronomical observatories. Maximilian Hell was so successful in setting up smaller observatories that in 1755 Maria Theresa of Austria and Hungary named him her court astronomer and commissioned him to organize a great central observatory in Vienna. He did so and remained its director for a quarter century. For 37 years he published his unique periodical Ephemerides Astronomicae containing scientific papers and observations which was widely used by the imperial navy, for purposes of the merchant fleet, geodetic surveys and the exact mapping of the empire.

In 1767 he accepted an invitation from King Christian VII of Denmark and Norway to direct the scientific expedition to the island station Vardø near Lapland within the Arctic Circle. The purpose was to gather data from the 1769 transit of Venus which crosses the face of the sun about twice a century. If the contact points of the sun with Venus, upon entering and exiting the sun's circumference, are properly observed from different vantage points on earth, this transit can provide data needed for computing the solar parallax, which can then be used to compute that elemental astronomical unit, the sun's distance to the earth. This adventure was an effort by scientists of various nationalities to simultaneously collect data in Vardø, Manila, Batavia, California, Peking, and Tahiti. The value of the sun's distance accepted today, 93 million miles, was determined at a later date when finer instruments and better methods were available. This 1769 effort, however, was significant because it was among the earliest examples of international scientific cooperation.

The day of the transit was 3 June, 1769 and the observers had the good fortune to have clear weather to make their observations, for which they sang a Te Deum in gratitude. Hell and his team stayed in Vardø for about eight months, spending most of their time collecting other scientific data for an anticipated encyclopedia concerning the arctic regions. This was to contain studies in biology, meteorology, oceanography, zoology, geography, natural history and linguistic analysis. Hell saw the transit as only one part of a larger expedition. Nothing came of Hell's encyclopedia, however, because of the Suppression of the Society in 1773.

Meanwhile the astronomers who had stayed home were anxious to get his observations, since Hell's ability to observe was considered the most reliable of the scientists involved. Hell, however, felt his first priority was to report to his Danish sponsor and would not be hurried or coerced. This irritated the French Academy who accused him of having nothing to report and of waiting so that he could create figures to correspond with the observations made elsewhere. This accusation implied the worst crime a scientist could commit. Eventually in 1772 Hell's observations with all their intricate detail were published.

For a time the ugly insinuations ceased until Carl Littrow became one of Hell's successors at the Vienna observatory with access to all the records. When Littrow found Hell's original data sheets concerning the 1769 transit he claimed to finally have evidence that Hell's figures had been falsified. He asserted that the data contained erasures which were corrected by scratching in a slightly different colored ink. This indictment of Hell was more serious than the original vague insinuations because it seemed to carry the aura of scientific proof. Thus was Hell discredited and his reputation as a reliable scientist destroyed.

It was not until a century later when the American astronomer, Simon Newcomb who was especially interested in the rare transits of Venus, examined Littrow's evidence and found it fictitious. Newcomb found that Hell's figures were exactly what they should have been. They were much more in accord with the true value of the parallax than the data of any other observer. The scratched out figures were merely a matter of Hell using a defective pen in the cold arctic air. Alterations had indeed been made by rubbing out the ink with a finger. But unquestionably this had been done before the ink had dried, not months later as had been charged. Finally, Newcomb discovered that Littrow was colorblind. In fact his defect was so severe that he "could not distinguish the tint of Aldebaran from the whitest star." Newcomb's imposing stature was such that all the charges against Hell were declared spurious by all astronomical societies. Hell was vindicated and his illustrious reputation recovered.