By Steven van Roode
By the time of the transit of Venus on 1769 June 3 astronomers knew what to expect, because the previous transit only had occurred eight years earlier. Again, a few astronomers were sent to remote places to measure the transit, among which James Cooks journey to Tahiti is well-known. This time the transit was also observed for the first time from a great number of places in the New World.
In the Dutch East Indies, the Reverend Johan Maurits Mohr undertook to build a fully equipped private observatory in Batavia in 1765 (now Djakarta, Indonesia). He observed the 1761 transit of Venus also from Batavia, but with just a few simple and unreliable instruments. Now, eight years later, he owned a marvelous observatory with the best astronomical instruments available. Mohr could observe the egress of Venus “bright, sharp and precisely”. The observatory was damaged by an earthquake in 1780 and demolished in 1812.
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Location: 6°08′37″.9 S, 106°48′46″.5 E times of contact
In April 1769 after an eight months journey James Cook, commanding the Endeavour, arrived at Tahiti to observe the transit of Venus for the Royal Society. To secure his temporary observatory he constructed a fort at a northern promontory called Point Venus. On the day of the transit the sky was clear and Cook could observe the whole transit, assisted by Joseph Banks and astronomer Charles Green. There is a monument close to the lighthouse at Point Venus to commemorate Cook’s observation, but the plaque has been stolen en never replaced.
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Location: 17°29′42″.8 S, 149°29′40″.8 W times of contact
By order of the Royal Society William Wales and Joseph Dymond observed the 1769 transit of Venus from Prince of Wales Fort, Manitoba, Canada. The fort was located on Hudson Bay on the west bank of the Churchill river. They constructed two observatories on the south east bastion of the fort. These observatories had been designed by John Smeaton, civil engineer of the Royal Society.
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Location: 58°47′48″.7 N, 94°12′46″.6 W times of contact
In 1769 David Rittenhouse observed the transit of Venus from an observatory built on his own farm in Norriton, near Philadelphia in Pennsylvania. Rittenhouse, a distinguished clock and instrument maker, noticed a faint halo around the planet before ingress. Nowadays the place is indicated by a historical marker at the driveway entrance of 1033 West Germantown Pike, Norristown. The original observatory was 700 feet north-east from the marker.
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Location: 40°09′29″.3 N, 75°22′02″.9 W times of contact
From an observatory on State House Yard in Philadelphia, Pennsylvania John Ewing observed the 1769 transit of Venus. During the event curious crowds filled the square, doing their own observing through pieces of smoked glass. The observatory was located 40 feet due west from the rear door of the present Philosophical Hall and the same distance south from the present eastern wing of the State House.
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Location: 39°56′55″.4 N, 75°08′58″.9 W times of contact streetview
Southwest of the town of Lewes, Delaware, from a house in a retired situation, Owen Biddle, Joel Bailey and Richard Thomas observed the 1769 transit of Venus. Biddle used a refracting telescope on a equatorial mounting magnifying 150 times, while Bailey used a telescope by Dolland mountd on ball and socket. Exterior and interior contatcs at ingress where seen by both men.
Location: 38°46′12″.9 N, 75°08′20″.6 W times of contact
From his residence Stirling Manor in Basking Ridge, New Jersey, William Alexander (Lord Stirling) observed the 1769 transit. The house burnt down in the mid-1800s and was replaced by another, which in turn burnt in 1919. In 1920 the present house was built. Only the cellar of Stirling′s original house still exists as part of the current house.
Location: 40°41’41″.4 N, 74°31′48″.8 W times of contact
In Providence, Rhode Island, Benjamin West erected a temporary observatory on the crest of a hill one hundred feet east of Benefit Street at wat is now known as Transit Street. A 4-inch Gregorian reflecting telescope and a measuring device were purchased by Joseph Brown from Watkins and Smith of London. On the day of the transit, while crowds of curious spectators gathered at the observatory, West, Brown and Governor Stephen Hopkins made their observations until sunset. The telescope used by West is now on display in the John Hay Library at Brown University.
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Location: 41°49′13″ N, 71°24′04″ W times of contact streetview
From his new house just two and a half miles outside Québec, surveyor-general Samuel Holland observed the 1769 transit of Venus together with S. Germain of the Québec Seminary. In March, when he moved in, he started determining the latitude and longitude of the place right away. On the day of the transit, he could time first contact, but the observation of the second contact was prevented by intervening clouds. The house of Holland was demolished in 1843 and replaced by a new residence, which in turn was torn down in 1967 to make place for the YWCA. Learn more…   
Location: 46°47′40″.2 N, 71°15′04″.6 W times of contact
From his house in 14 Clarke Street, Newport, the Reverend Ezra Stiles observed the transit of Venus on a fine serene day. Stiles was with William Vernon at the meridional threads, while Henry Merchant was at the 18-inch reflective telescope, Benjamin King at the tube of the quadrant and Henry Thurston with a good prospective. In the house were two clocks, one of Christopher Townsend and one of Stiles. Each clock was watched by two assistants.
Location: 41°29′21″.6 N, 71°18′48″.1 W times of contact
In May 1769 Samuel Williams was invited by Tristram Dalton to observe the transit of Venus from his country house in Newbury, Massachusetts. The estate, of Georgian architecture, was in a high elevated location, which was very convenient for the purpose. They observed with a reflecting telescope by Nairne, magnifying about 55 times. Dalton’s original country house was on Pipe Stave Hill in modern West Newbury, but has been demolished in the nineteenth century.
Location: 42°48′31″.8 N, 70°57′43″.9 W times of contact
In 1769 Charles Mason travelled to the townland of Cavan in the county of Donegal to observe the transit of Venus on behalf of the Royal Society. The instruments, a 12-inch quadrant by Bird, a 2-foot Gregorian telescope and a clock by Shelton, were housed in an observatory with a movable top. Mason observed both cotacts at ingress. His exact observing location is unknown, but it is believed that Mason observed from the vicinity of a farmhouse just north of Cavan.
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Location: 54°51′47″.8 N, 7°30′04″.8 W times of contact
From the villa of Lord Alemoor at Hawkhill near Edinburgh, three observers watched the 1769 transit of Venus. From the nearby observatory with a movable roof James Lind observed with a 2-feet achromatic telescope. On the ground-floor of the villa was James Hoy with a 3½-feet achromatic telescope and on the floor above was Andrew Pringle, Lord Alemoor, with an 18-inch reflector. The day was cloudy with occasional showers. However, at the time of ingress, the clouds disappeared and both contacts at ingress could be timed. Lind’s telescope is now at the Science Museum, London.
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Location: 55°57′49″.8 N, 3°09′34″.0 W times of contact
At the observatory of his large Austhorpe Lodge estate, near Leeds, engineer John Smeaton tried to observe the 1769 transit of Venus, but was clouded out. The observatory consisted of a square tower, four stories high, standing apart from his house, which also contained a shop and study. The Lodge was demolished in the late 1930’s. The next day, Smeaton was successfull in observing the solar eclipse.
Location: 53°47′55″.2 N, 1°26′20″.5 W times of contact
In Oxford, in the upper room of the Tower of the Five Orders, Thomas Hornsby observed the 1769 transit of Venus. He timed the internal contact at ingress as accurate as the unsteadiness of the floor would permit with refractors of 12 feet and 7.5 feet focal length. Due to the black drop effect, Hornsby estimated the uncertainty of his timing to be about one minute. Learn more…
Location: 51°45′14″.8 N, 1°15′14″.7 W times of contact
From the observatory at Shirburn Castle, Thomas Parker, 3rd Earl of Macclesfield, observed the 1769 transit of Venus, together with two assistants John Bartlett and Thomas Phelps. In the afternoon the sky was free of clouds, but charged with vapour. This occasioned a constant undulation of the solar limb.
Location: 51°39′30″.1 N, 0°59′39″.6 W times of contact
England’s first ecologist Gilbert White observed the 1769 transit of Venus from his own garden in Selborne, Hampshire. According to White, the spot of Venus was very visible to the unaided eye when the sun was very low just before sunset. Today, the house of White in Selborne is a museum.
Location: 51°05′51″.0 N, 0°56′36″.3 W times of contact
From the Round Tower at Windsor Castle Daniel Harris observed the 1769 transit of Venus. At the day of the transit nobody was admitted into the Round Tower but Harris and his assistants. The weather was very favourable, exept for the wind. Learn more…
Location: 51°29′02″.3 N, 0°36′15″.5 W times of contact
In 1769 an observatory was designed at Richmond, Kew specifically for the royal family to observe the transit of Venus. With a reflecting telescope made by James Short, George III was the first to observe external contact. Learn more…
Location: 51°28′08″.0 N, 0°18′52″.8 W times of contact
The eminent merchant and amateur astronomer Alexander Aubert observed the 1769 transit of Venus from his home at 26 Austin Friars, London. He used a cassegrain reflector by Short with a focal length of two feet.
Location: 51°30′54″.6 N, 0°05′08″.2 W times of contact
From his home at 3 Spital Square, London, physicist John Canton observed the 1769 transit of Venus. His observations were made under disadvantageous circumstances of being on top of the house and seeing through smoke. The house was demolished in the 1920’s. Learn more…
Location: 51°31′13″.0 N, 0°04′35″.5 W times of contact
At the Royal Observatory in Greenwich the 1769 transit of Venus was observed by Astronomer Royal Nevil Maskelyne. The weather had been cloudy and rainy all day, but towards the approach of Venus’ ingress on the sun, the sky cleared. Maskelyne could time both external and internal contact at ingress. He observed the aureole and the black drop effect.
Location: 51°28′40″.8 N, 0°00′07″.1 W times of contact
Accompanied by Spanish officers, astronomer Jean-Baptiste Chappe d’Auteroche set of for a long journey to the southern tip of Baja California, where he arrived in May 1769. He converted an abandoned barn on the grounds of the mission of San José del Cabo Auñuití into an observatory. His expedition was a success, but afterwards almost all of Chappe’s staff, including the astronomer himself, died of an epidemic. At the Casa de la Cultura there is a plaque commemorating the expedition.
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Location: 23°03′47″ N, 109 °41′40″ W times of contact
On the roof of his house in the Rue des Fleurs in Toulouse, François Garipuy had an octogonal observatory measuring 6.5 meters in diameter. From here, he timed internal contact at ingress observing with a gregorian telescope of 22 inch, equipped with a heliometer and a micrometer. After Garipuy’s death in 1782 the observatory was used by the Académie des Sciences until 1846, when a new observatory was built in Toulouse. There is a stone marker commemorating the observatory.
Location: 43°35′38″.9 N, 1°26′45″.4 E times of contact
From the observatory at his house in 8 Rue Darquier in Toulouse, Antoine Darquier de Pellepoix observed the 1769 transit of Venus. He used a reflector of 18 inch made by Short. The setting sun became visible from behind low clouds only a quarter of an hour before the interior contact at ingress. Darquier observed this phase with great attention and judged that he timed the contact quite accurately. There is plaque commemorating Darquier.
Location: 43°35′41″.6 N, 1°26′46″.8 E times of contact
At the Cabinet de Physique of King Louis XV at the Château de la Muette near Paris astronomer Jean-Paul Grandjean de Fouchy observed the 1769 transit of Venus. The building of the Cabinet de Physique was in the extremity of the garden. De Fouchy was accompanied by Gabriel de Bory and Jean-Sylvain Bailly. Two others, father Noël and Abbé Bourriot, also took part in the observations. Today, the original Château de la Muette has completely disappeared. Learn more…
Location: 48°51′31″.1 N, 2°16′17″.4 E times of contact
In spring 1769 a new observatory had been constructed at the École Royale Militaire in Paris. However, professor of mathematics Edmé-Sébastien Jeaurat didn’t make use of it for observing the 1769 transit of Venus, because from the observatory he couldn’t follow the sun until sunset. Instead, he installed his instruments in a room in one of the new pavillions of the building.
Location: 48°51′09″ N, 2°18′12″ E times of contact
At the Observatoire Royal in Paris several persons observed the 1769 transit of Venus. Director of the observatory César-François Cassini de Thury was in charge of the observations. Other observers were Michel Ferdinand d’Albert d’Ailly (Duc de Chaulnes) and Achille-Pierre Dionis du Séjour. Astronomer Jean-Dominique Maraldi also took part in the observations. Learn more…  
Location: 48°50′10″.8 N, 2°20′11″.4 E times of contact
At the Collège Mazarin Joseph-Jérôme le François de Lalande observed the transit of Venus from the observatory founded by Nicholas Louis de la Caille. The observatory consisted of a small tower built on the solid arches next to the dome of the chapel. Lalande had a fine achromatic telescope by Dollond. However, due to rain he wasn’t able to observe the interior contact at ingress directly. He was accompanied by abbé Marie, who was professor of mathematics at the college.
Location: 48°51′25″.8 N, 2°20′12″.7 E times of contact
At the observatory tower of the Collège Louis-le-Grand, there were two observing parties: Charles Messier and Boudoin on the upper floor and Turgot and Zannoni on the lower floor. Messier observed with an achromatic telescope of 12 feet focal length, but was hindered by clouds and rain.
Location: 48°51′25″.8 N, 2°20′12″.7 E times of contact
French astronomer Guillaume le Gentil de la Galaisière was very unfortunate in observing the transit of Venus. In 1761 he was heading for Pondicherry, a prominent French fortified town in India. But before his arrival the town was captured by the British and razed to the ground. In 1769, when Pondicherry was again under French control, Le Gentil set up his instruments in the ruins of the former Governor’s palace, but was clouded out on the crucial moment.
Location: 11°56’03″.9 N, 79°50′02″.4 E times of contact
In 1764 a new observatory was built on the roof in the centre of Schwetzingen Castle. It consisted of a cupper covered dome measuring 3.25 meters, surrounded by a small catwalk accessible directly from the bedroom of the prince. From this new observatory Prince Franz Xaver von Sachsen and Elector Carl Theodor tried to observe the 1769 transit of Venus, but bad weather made it impossible to see Venus on the setting sun.
Location: 49°23′02″.5 N, 8°34′14″.3 E times of contact
From the tower of the Dreieinigkeitskirche in Sankt Georg near Hamburg, German astronomer Johann Elert Bode observed the 1769 transit of Venus. The sun set shortly after the start of the transit, but Bode could observe ingress. The tower and the church were almost completely destroyed in 1943 during an air raid. In the 1950’s the church was rebuilt and the tower was reconstructed.
Location: 53°33′22″.9 N, 10°00′28″.1 E times of contact
From his observatory at the Grauen Kloster in Eldena, just outside Greifswald Lambert Heinrich Röhl observed the transit of Venus, together with Andreas Mayer. By then, the monastery was already a ruin and used as a stone pit to obtain bricks.
Location: 54°05′21″.4 N, 13°27′09″.3 E times of contact
From the observatory of the Imperial Academy of Sciences in St. Petersburg, Christian Mayer observed the 1769 transit of Venus with a refracting telescope of 18 feet focal length. Mayer was accompanied by Leonhard Euler, Anders Johan Lexell and Stahl. They had to use the upper floor of the observatory, because from the lower floor the eastern horizon couldn’t be seen (only the last part of the transit was visible just shortly after sunrise).
Location: 59°56′29″.4 N, 30°18′16″.1 E times of contact
The observatory of the university of Lund, Sweden was located on top of the round tower of the Lundagårdshuset. From this observatory the 1769 transit of Venus was observed by Nils Schenmark, professor of mathematics and astronomical observer. He was accompanied by Olof Nenzelius. Both men timed external and internal contact at ingress, while the sun was low.
Location: 55°42′19″.4 N, 13°11′38″.7 E times of contact
From Uppsala Observatory astronomer Mårten Strömer watched the 1769 transit of Venus with a reflector of 3 feet focal length. Only ingress was visible from Uppsala, and Strömer could time first and second contact. Next to Strömer observations were also made by Torben Bergman, Daniel Melander, Erik Prosperin and Salenius.
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Location: 59°51′35″.6 N, 17°38′13″.0 E times of contact
At the observatory of the Royal Swedish Academy of Sciences in Stockholm, Pehr Wilhelm Wargentin used his 21 feet telescope to observe the 1769 transit of Venus. Bengt Ferner and Johan Carl Wilcke were also observing with a 10 feet telescope by Dollond and a 1½ feet telescope respectively.
Location: 59°20′29″.4 N, 18°03′16″.6 E times of contact
Upon his arrival in Vardø, Norway in October 1768, Jesuit Father Maximilian Hell started to construct a wooden observatory in the centre of the village, at Valen near the modern Town Hall. The observatory, completed in January, had several hatches in the roof and walls through which Hell and his assistants could observe the sky. For a long time it was thought that Hell falsificated his observations of the 1769 transit of Venus until in 1883 Simon Newcomb proved otherwise. After Hell left Vardø, the observatory fell in decay and in 1876 the building was completely gone. Nowadays, there is a plaque to commemorate Hell’s observation.
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Location: 70°22′13″.2 N, 31°06′25″.0 E times of contact
From the roof of the Casas del Cabildo at the central square in Mexico City José Ignacio Bartolache, together with José Antonio Alzate and Antonio de León y Gama, observed the 1769 transit of Venus. They timed first internal contact, but about four hours later the sun disappeared behind dense clouds. During the transit, Alzate also made observations of sun spots. In the early 1900’s the building has been greatly altered and today it houses the Palacio de Gobierno del Distrito Federal.
Location: 19°08′03″.3 N, 99°25′54″.9 W times of contact
The observatory of Cádiz, founded in 1753, was located on Torre del Homenaje of the Castillo de la Villa. Vincente Tofiño became director of the observatory in 1768, a year before the transit. On the day of the transit, shortly before sunset, he observed both contacts at ingress with a telescope of 7 feet focal length. The Torre del Homenaje stood on the southeast corner of the castle, near the corner of the modern Calle de San Juan de Dios and Calle Campo del Sur. During the nineteenth century, the Castillo de la Villa progessively fell in decay, until in August 1947 the already most scarce traces were destroyed by the explosion of a naval arms store.
Location: 36°31′41″.5 N, 6°17′35″.5 W times of contact