Venus Transit -
The Portuguese contribution and German participation on the international
campaign of 1874 and 1882
Common Project of
Escola Secundaria de Albufeira (P) and Schloßgymnasium Düsseldorf (D)
is when a star or an astronomical body passes in front of another greater
without occulting. In the eclipses, one of the objects hides the other
significantly. A transit of Venus or Mercury in front to the sun is
therefore the visual travel of one of these planets for our star. What it
is seen is only one small point to pass slowly in front to the sun, so small
that we have to be prepared to see. Mercury and Venus are inner planets,
which pass in front to the sun. During centuries, nobody saw Mercury or
Venus to be crossed in front to the sun. Some medieval astronomers had
arrived to think that this happened for these two planets because they were
In beginning of XVII century, the german astronomer Johannes Kepler supposed
that the orbits of the planets were ellipses and this allowed to foresee the
movement it of the astros with much severity and to verify that exacts
alignments of planets were rare. Build tables that had been famous, the
Rudolfinas tables. When making the calculations to complete them, perceived
that Mercury if went to interpose between the Earth and the sun in 1631.
Died one year before this date and cannot verify if his prediction was
right. Kepler was the first one to understand the reason because the
mercury transits and Venus are rare. Pierre Gassendi had in account the
invites made by Kepler and started to observe Mercury two days before the
date that this had foreseen. Pierre Gassendi was the first astronomer to
observe a planetary transit, Kepler had made a mistake in only five hours!
The first transit of Venus was seen in 4 of December of 1639 by Horrocks.
This remade the calculations of Kepler and verified that this had left to
pass the 1639 transit. Throughout centuries the Astronomers had obtained
reasonable estimates of the relative distances of the solar system.
After Copernicus and Kepler, disposal of the planets and its orbits was
known it. For extraordinary creative geometric processes, it was obtained a
reasonable idea of the relative distances in the solar system, but it lacks
to know in the distance absolute (real) of the Earth to the Sun. Halley
understood that a transit of a planet would allow to discover this
distance. This English astronomer suggested that the transit was observed
from different places, it was possible determine the solar parallax and the
astronomical unit (dist. Earth-Sun) different one.
Halley had correspondence with other astronomers, as Deslile that also was
corresponded with many astronomers (mainly European). This astronomer
proposed alterations to the method considered for Halley to calculate the
solar parallax, according to it, it was not necessary to observe all the
transit but at least one or two moments (entered and exit).
Deslile sent letters with instructions for many countries and among these
countries was Portugal, where its main interlocutor was João Chevalier. João
Chevalier had a relation of great friendship with another portuguese
astronomer, Teodoro de Almeida. João Chevalier could not observe the
transit of Venus of 6 of June of 1761 because political reasons, he was
forced to running away for France in 1760. Teodóro de Almeida was exiled in
the city of Porto to the date of the transit of 6 of June of 1761. It
observed the transit of the planet and elaborated a register that the João
Chevalier sent to Paris, and arrived at the hands of Deslile. For beyond
Teodoro de Almeida, the transit of Vénus of 1761 still was observed by
others two Portuguese observers, Miguel Ciera in Lisbon (in the “Colégio dos
Nobres”) and Soares Barros in Paris (in the monastery of Genoveve Saint).
de Almeida is placed with frequency in a list of 20 detached observers of
the transit of 1761 of about 120 that observed the transit it, fact that
demonstrates the attributed importance to this comment.
Teodoro de Almeida (1722-1804)
Observation of Teodoro de Almeida, publish in “Mémories
de Mathématique et Physique, Presentés à l’académie Royale des Sciences, par
divers savants & lûs dans ses assenblées, 1774 (Bibliothèque Nationale de
The German expeditions of 1874 and 1882
the “ Deutsches Kaiserreich (1871-1918) “ five expeditions to the
Venustransit 1874 and four expeditions to the Venustransit 1882 were
prepared. They were coordinated by the astronomers Auwers and Foerster. The
best conditions for observing Venustransit 1874 were given in the Indean
Ocean. To reach a noticeable effect by the parallax-effect the
observation-stations were built in the northern hemisphere in Tschifu
(China) and Isfahan (Persia), and in the southern Hemispere in Mauritius, in
Kegulen (French South Territories) and in Auckland (South of Newseeland).
The first expedition (Tschifu) was performed by Wilhelm Valentiner,
astronomer from Leiden (Netherlands), Carl Adolph from Elberfeld (today
Wuppertal), Eugen Reimann from Ratibor (Oberschlesien) and the photographer
Carl Kardaetz from Franzoesisch Buchholz near Berlin. Two assistants were
added: the mechanic Friedrich Deichmüller from Leipzig and the painter
Oskar Eschke from Berlin.
month trip from Southampton to Shanghai was overcome with English steamers;
with a small ship they arrived at Tschifu on October 27th - in addition to
the expedition members, 107 bags of 14 tons of weight in total. The station
was surrounded by a wall and secured, where the team of the ship Arcona
that was stationed in East Asian waters, gave help. We take the following
from a letter of Kardaetz from Tschifu:
before we were afraid because of the bad weather, full with thousands of
fears. Sleeping was not possible. We had luck, the wind turned and chased
the clouds. At night around 3 o'clock we had the most marvellous sunrise.
Everything was at early 7 o'clock in its place. Mr. Baron of Reibnitz,
Commandant Sr. Majesty’s ship Arcona said: » The location looks like the
deck of a tank frigate, which is clarified for the fight.«. All ships in the
port had flown flags, all ambassies showed flags and many private houses
presented their festive flags; the Chinese in the city burned down fireworks
at sunrise and asked for a clear sun through it. The requests are
fullfilled, because we had quite clear weather about two hours long. To end
of the phenomenon namely with the last plate, it was also past as cut off,
the sky wrapped itself completely in clouds. Day after we had in the morning
snow and hail«
The members of expedition 2 (Bettsy Cove, Kerguelen lsland) were Carl Börgen,
director the Navy-Observatorium in Wilhelmshaven, Arthur Wittsteinkind from
Munich, Theophil Studer of the Zoological Museum of the University of Bern,
Ladislaus Weinek from Budapest, the photographer H. Bobzin and of the
mechanics Carl Krille, both from Schwerin.
The Kerguelen expedition was part of an almost two-year investigation trip
by the steam corvette “M.S. Gazelle” which was also used for oceanographic,
geographic and zoological investigations. The gazelle left Kiel on June
21st , sailed to Capetown, and arrived in Betsy Cove on October 26th, and on
the next day began the look-up to a place for the station.
Börgen noted : »An of the southern side of the Cove arises the terrain to a
hill which ascends in the last 40 feet at steep rock measures. On half
height tipped over us we saw a number white crosses which signed the graves
of the whale hunters. The only to some extent dry spot that was also flat
found itself above the graves. We decided to choose this place for our
Ladislaus Weinek wrote his impressions the Venus transition :>> It rained
in the evening of December 8th: at the 9th, the day of the phenomenon, the
sun rised clear and friendly. The entry of Venus into the solar disc was
immediately after 6 ½ o’clock in the morning, the withdrawal at 11 o'clock.
Several minutes before the calculated time everybody hurried on his posts,
the astronomers to their telescopes, the photographer into the darkroom,
Börgen stood at the heliometer, Weinek at the refractor and the Wittstein at
the telescope.- Meanwhile the sky was covered by a rather dense cloud veil;
in the west over the snow covered mountains were stored dark clouds. The
Venus, a small black spot of 1/30 of the solar diameter, began to shift
itself into the sun. We expected the so-called second or inner touch of the
two edges with tension; because if we could observe the phenomena in a
successful manner, we could say, we were not in vain in this unhospitable
region The crucial momentum already approaches, everybody looks again to
the ticking chronometer in order to control the seconds counted in thoughts.
The Venus already seems to want to free itself from the solar edge, a
bridge is build, which becomes thinner and is divided. This was the
momentum to be observed. We had fixed him with joy. - while the Venus is now
freely in the sun, the work of an astronomer changes; now begin the distance
measurements of Venus from solar center Börgen remained at the eyepieces of
the heliometer, Wittstein determined continuously the scale of the objective
; on the other hand, Weinek accompanied by Crille hurried to the
photographic heliograph. The first one did the exposition, the second
changed the photographic plates, which were processed by Bobzin and Studer
in the darkroom.
[...] We were satisfied with the images of the transit especially since the
observation of the inner and external contact of Venus also succeeded
completely. After December 9th bleak and stormy weather followed [...]again
so that we had to wait until December 19th, to do futher sun photographs
End of January the station was broken off and we started the trip home. We
arrived in Mauritius on February 26th, where the astronomers travelled back
with a mail steamer, while the ship Gazelle continued its trip with Dr.
Studer around the world. He returned in April 1876 to Kiel.
The third expedition (Port Ross, Auckland Island) consisted of two
astronomers, Hugo Seeliger (Bonn) and Wilhelm Schnur (Strßburg), two
photographers Herrmann Krone and G. Wofram (both Dresden), and two
assistants, the mechanic Leyser jun. (Leipzig) and Johannes Krone (Dresden).
participants traveled to Melbourne by means of steamers in 53 days of London
where they were already expected by Seeliger and two naval officers. The
chartered bark» Alexandrine « transported the researcher, cases and a
wooden residential building to the Auckland Island, where the station was
built up at the shore of the Terror Cove close to the settlement Port Ross.
October 1874 18th until March 1875 6th, the Auckland station remained
acting. The best insight offer the images, reports and poems by Herman Krone
, one of the pioneers of photography. He published in journals, he made
three video series the Auckland islands, and he wrote several volumes around
1900 in which the events of 1874 are reported in form of a modern Odyssee.
fourth expedition (Solitude, Mauritius) consisted of the two astronomers
Moritz Loew (Berlin) and Carl Frederik Pechüle (Hamburg) and two assistants,
the mechanic Herman Doelter from Strassburg and the janitor of the
Goettinger observatory, Dietrich Heidorn.
had chosen Mauritius, because in the case of possible failures of the
expeditions to Kerguelen and Auckland a further, meteorologically more
reliable southern site is available. A free face, close to an uninhabited
country house - Solitude -, place in the southeast of the island at a
railroad track appeared as a suitable site because in the northeast, an
English expedition has found a location for their observations. The weather
was extremely bad, some heliometer measurements nevertheless reach through
The four members of expedition 5 (Isfahan) were the photographer Gustav
Fritsch, assistant on the anatomical institute of the Berlin university, the
astronomer Ernst Becker, Observator at the Berlin observatory and two
further photographers, Franz Stolze from Berlin and Hugo Buchwald from
the thrilling personalities of the project belonged to this expedition.
Franz Stolze was the son of the inventor of stenography »System Stolze«. At
the end of his astronomical studies, he participated in an archaeological
expedition, his series of photographic images appeared as a collection»
Persepolis «. He developed a new gas turbine in Berlin later. Gustav Fritsch
led an immotional and versatile life. A three year trip through Africa was
reported in an adventure book in the way the german author Karl May wrotes
his famous stories. Astronomical expeditions followed to Aden and Isfahan.
He wrote scientific treatises on electrical pisces, the eye and the growth
of hair of the human being. A combination of the combination of anatomy, art
and photography he published in his book »Nackte Schoenheit«, where for
photographs of »Akteurs« of every sex and of every age are shown with
critical comments of Fritsch. Such a colored bird had little chances in the
academic hierarchy: His career ended as a extraordinary professor.
trip of the Persian expedition started with the railroad trip to Wolgograd,
then with a steamer on the Wolga to Astrachan, over the Kaspian Sea to the
port of Rescht, then with a caravan of 58 pack-animals to Teheran. After an
audience of the Schah, the caravan continued its way to Isfahan where a »Gartenpalais(
gardenhouse)« was constructed in the direct proximity of the astronomical
The photographic observations to those one had linked great expectations
proved as a disappointment. The heliographs had no parallactic mounting with
an exception because exposure times were chosen so short, that the sun was
represented sharply. In this case, one had ignored that turbulence of the
air unrest can cause a strong distortion of the pictures. Wilhelm forester
writes in his life memories and life hopes (1911):
our preparatory works we tied to limit the effects of sunlight on the
photographic plate to the shortest possible time, and we succeeded, in
limiting the time of exposure of the plate to ten thousand of a second. We
could attain sharp pictures of the solar disc and of the details [...] only
this way. When however we now went to the finest measuring of the
photographic solar images of our Venus expeditions of 1874, the solar
pictures were completely unsuitable for the finest measurement results,
namely because of the until then not sufficiently recognized enormous
variations, which the direction of propagation of the rays of light suffer
by the steady modifications of the states of the different regions of the
The solar edge was defined badly, the Venus picture appeared distorted.
Auwers, as a classical astronomer with critism towards the modern
photography, decided without far too big resistance of team to refuse
completely to photographic images for the Transit of 1882, not only from
The costs might at this point be mentioned: the effort of the photograph,
the higher personnel costs and costs of materials combined with expenditures
for building observation stations at faraway places resulted in the fact
that the expeditions in 1874 being more expensive than the later ones:
620000 marks compared to 80.000 Euro. About 2/3 pure expedition costs and
1/3 was employed for instruments, domes and other costs. The total costs
correspond to a contemporary value of about twelve millions Euro - for
instance, '/3 of the German year contribution to the European southern
Expeditions of 1882
The Venus transition was favorably to observe in the western hemisphere.
Four expeditions were furnished in 1882: two to the United States (Hartford,
Connecticut and Aiken, South Carolina), one to Argentina (Bahia Bianca) and
one to Chile (Punta Arenas). In addition, the German polar expedition had
been equipped on the island of Sued-Georgien with a dome sited south of the
Falklands and a fifth heliometer.
The first expedition (Hartford) consisted of four participants, Gustav
Müller, assistant on the astrophysical observatory in Potsdam, Friedrich
Deichmüller, observator of the Bonn Observatory, the student of astronomy
Julius Bauschinger from Munich and the technical assistant Herman Doelter of
Diedenhofen (Thionville, Lorraine). The later had already assisted in
delegation accepted an invitation of professors of the Trinity college sited
outside of the city to build up the station there. Their activity is
documented in a long official report of Müller and a contribution in Frank
Leslie's Illustrated Newspaper. One the day before the transition the snow
melted, it rained at the night, and it was in the morning cloudy. The sky
cleared up an hour to entry. The team began with measurements on the
heiometer. However the third contact was disturbed by clouds a little.
The four members of second expedition (Aiken) were Julius Franz, Observator
at the Königsberger Observatory, Herman Kobold, Observator at the Konkoly-Observatory
in Hungaria, the Adolf Marcuse, astronomy-student of Berlin and the mechanic
F. Carl of Würzburg.
Franz gave a
full report in the “ Schriften der Königsberger Gesellschaft”.
started by steam-ship to New York and from there with the railroad to Aiken
in South Carolina. This small city with only 2000 inhabitants is steadily
growing and from many foreigners because of the mild climate is considered
as a climatic health resort. The station was constructed at the northern
edge of the city.
In the morning of the decisive day the sky was covered, however, cleared
itself gradual. The first test of 16 observations occurred through dense
clouds, two further through lighter veils. On December 22nd, the team
returned from New York to Hamburg on the steamer Cimbria, that - for luck
for the astronomer – sank during its next crossing of the Atlantic to the
bottom of the ocean.
members of the third expedition (Bahia Bianca) were Ernst Hartwig, assistant
on the Strassburg-Observatory, Bruno Peter, Observator on the
Leipzig-Observatory, the astronomy student Walter Wislicenus from Strassburg
and the mechanic H. Mayer from Munich.
wrote a report for the bulletin of the Academy in Cordoba whom we take the
following: The trip was made on steamers of Hamburg to Buenos Aires and from
there with a small warship of the Argentine Government to Bahia Bianca. As a
location a small farm was chose about one mile west of the small town. Peter
writes: » The used terrain was fenced in with strings in order to protect it
against the animals which free in the pampas lived. «
On the day of the transition the sun rose in a cloud shift and was visible
only few moments. The clouds removed themselves ten minutes before the first
contact, the contact was observed. But clouds then shifted themselves before
the sun again. It cleared, two series of measurements are done, strong wind
drove new clouds here, it began to may rain. Then the sun was visible again,
the measurements became consecutive, and also the third and fourth contact
could be observed.
fourth expedition (Punta arena) consisted of the astronomers Friedrich
Kuestner and Paul Kempf from Berlin, the geologists Gustav Steinmann of
Straßburg and the mechanic Friedrich Schwab from Marburg. Auwers decided to
follow the expedition. They traveled with the steamer to Montevideo and long
from there one after Punta arena. The official report only quotes short
We let follow some arcades of public speech published from Auwers'
elsewhere: » The place [Punta Arenas] now only counts for instance one and a
half thousand inhabitants and is only a group wooden houses scattered on a
Their appearance in primitive forms and in the natural colour of weathered
wood fits just into the landscape.« At the lighthouse, the station was built
up. They began to prepare for the transition by means of observations at an
artificial model. Auwers writes: » In the afternoon of the 5th
[December] the rain at so normal thickness let our hopes sank deep. [...]
The rising sun rising made a transparently blue sky; only flocks of small
cumuli rose behind the Cordillere .« The first contact occurred and twenty
minutes later the important second: » Just the Venus is entering the edge of
the sun, a dense cloud slips before the sun. As she has gone one and a half
minutes later, Venus stands completely inside the sun.>> Nevertheless the
team succeeded in many heliometer observations as well as in the
determinations of the times of the third and fourth contact.
Expedition (Sued-Georgien) was a »non regular « undertaking. The expedition
of Germans Polar-Commission of the year 1882/83 led to the island Sued-Georgien.
The station in the Moltke-Bay was inhabited from August 20th, 1882 by
September 6th of the following year by eleven persons. The observations were
managed by Carl Schrader, an Observator of the of Hamburg Observatory. He
was assisted by the physicists O. Clauss and P.Vogel and the engineer E.
Venus transition occurred in the case of clear sky, however presumably
considerable air unrest. Mosthaff reports: »Most favorable ran the
observation of the Venus transition on December 6th, in spite of
vehement tempest that in such a way brought the revolving dome into danger
that the same has to be hold by three and four man on cables. nevertheless a
very favorable result was supplied, because the weather all day long was
bright and the sun remains clear.« From Auwers' comments follows, that
because of reading errors and of bad calibration of the employed heliometer
the observations of the Station Sued-Georgien was only of small benefit.
actual observations were finished. But further investigations of the
qualities of the heliometers were necessary. Little by little the results of
the expeditions, the instructions and reports, measurements and reductions,
and finally also the final results were published by Auwers: six
large-formats volumes, which contained more than 3600 pages were written.
Auwers was not only meticulous in the list of the reports and of the data,
he also held correct arrangement in his correspondence and in such a way,
the administrative unit of writings and answers exists in 110 files today,
manuscripts, bills, receipts, telegrams, sea boards, plans, photographs,
provided often with receipt stamp and inventory number.
Report of Auwers is only a aspect of the project. Expedition participants
wrote popular reports about their experiences - some samples were given
here. In letters of Fritsch to Förster, Fritsch claims on the often
“bookkeeping and arrogant attitude” of Auwers. Although only a correct
pedant could lead the project to a successful end, shared by different
temperaments of researchers and assistants. And how the result lookes like?
compiles all contact observations meticulously, without determining the
solar parallax after Halley’s method – no doubt with good reason – (Vol. 6,
P. 49). The results of the photographic observations of the four stops of
1874 (Vol. 6, P. 186) follow. A solar parallax derives Auwers from this
from 8.810 ± 0.120 arcseconds.
The detailed analysis of the Heliometer observations then follows (Vol. 6,
Auwers calculates a value of 8.8796 ± 0.0320 arcseconds. Interesting is,
that the photographic result includes the modern value of the solar parallax
(8.794142 arc seconds) within a disappointingly great mistake. The result of
the heliometer is almost 1 % too large. Apparently in case of the Heliometer
measurements there occurred systematical mistakes, whose existence Auwers
did not note and whose reason in our days cannot be revailed.
At the time, when Auwers closed the manuscript of the last volume, detected
Gustav Witt and Felix Linke at the Berlin Urania Observatory detected onto
single photography a minor planet that received the name Eros and that can
come very close to the path of earth. The Eros opposition of 1900 provided a
value of the solar parallax whose accuracy overcome all former values. In
this way, interest went out rapidly and thoroughly at the Venus transitions.
It awoke again, since such events again be present in our days.
Science will only give little attention to the phenomenon today. However in
amateur associations and schools the Venustransit is one of the thrilling
events in the life of the students and teachers.