History of the Observatory

The origins of the Pula Observatory can be traced back as far as 1840, to the Naval Observatory in Venice, which operated as part of the Austrian Naval Academy. After the upheavals of 1848, Austria closed the Naval Academy in Venice and in 1850 founded a new Naval Academy in Trieste, which included the Observatory as one of its departments.

Once Pula had become the main base of the Austrian Navy (K.K. Kriegsmarine) in 1853, systematic construction of fortifications began. That same year, work started on a fort on the town's Zaro hill (Monte Zaro), whose guns could reach almost the entire bay of Pula.

As defensive engineering and weapons technology advanced — above all the range and accuracy of artillery — and new forts were built farther from the town centre, Fort Zaro lost its original purpose. Meanwhile, the growth of the naval port created the need for an institution that would provide the Navy with scientific services, first and foremost for ever more precise navigation.

The Imperial and Royal Naval Observatory in Pula (K.u.K. Marine-Sternwarte) is the oldest astronomical institution in what is today the Republic of Croatia. To support precise navigation, four services were organised there, using instruments that were very modern for their time:

• Time servicetiming the meridian transits of stars and giving the time signal to ships in the harbour
• Chronometer servicecare of the ship's chronometers of the Austrian Navy
• Geomagnetic serviceamong other things, a geomagnetic map of the Adriatic published in 1913
• Meteorological servicemeasurements with instruments that were then state of the art

Besides its core duties, each service also made a scientific contribution. The staff of the Observatory department, who were military personnel, went beyond the tasks prescribed by the Statute and largely on their own initiative carried out other astronomical observations as well. Thanks to the exceptional dedication of the astronomer Johann Palisa, within about ten years (1871–1880) the Naval Observatory in Pula earned a permanent place among the world's eminent astronomical observatories.

That some of the instruments of the time are still standard equipment at weather stations is shown by the heliograph (sunshine recorder) — a simple instrument that measures the number of hours of sunshine in a day. Such an instrument still exists at the Observatory and is used for daily measurements.

After Pula

In 1880 Palisa was promoted to the Vienna Observatory, from where he discovered another 94 minor planets — 123 in total. As far as is known, he discovered all of them visually, observing through the telescope with the "naked" eye, and he still holds the record for the most visual discoveries. Together with Max Wolf of the Heidelberg Observatory he also produced a photographic star atlas.

In recognition by the International Astronomical Union, besides a crater on the Moon, two asteroids bear Palisa's name: (914) Palisana, named after him, and (1152) Pawona, named in honour of Johann Palisa and Max Wolf.

In his 71st year (1919) Palisa's eyesight began to fail. He died on 2 May 1925. On 15 October 2000 a memorial plaque was placed on the site of the house where he was born, bearing Palisa's favourite saying:

"Sic itur ad astra" — Thus one goes to the stars.

Palisa in space: 243 Ida

Space probes on their way to the outer planets of the Solar System had to pass close to some of the asteroids. Since Palisa mostly discovered large asteroids, some of them have been imaged by probes — namely the asteroids 243 Ida and 253 Mathilde.

To general surprise, images taken by the Galileo probe in 1993 showed that Ida has a natural satellite, named Dactyl. Because Ida was imaged in great detail, it became the first asteroid whose geological features were given names: three regions were named Palisa (after its discoverer) and Vienna and Pola (after the observatories from which Palisa hunted for asteroids).

The Navy Library (Marine-Bibliothek), later called the Imperial and Royal Navy Library (K. u. k. Marine-Bibliothek), was founded at the high command of the Austrian Navy in Venice in 1802, at the initiative of the Minister of the Navy and of War, Archduke Charles. From the very beginning it was a scientific and technical library serving the needs of the Navy.

At the request of the naval commander, Archduke Ferdinand Maximilian, Pula was developed in the 1860s into the main naval base of the Austrian Navy. In line with Vice-Admiral Wilhelm von Tegetthoff's plan for reorganising the Navy, the Hydrographic Office (Hydrographisches Amt) was established in Pula in 1869, and the Navy Library was incorporated into it as a separate department.

More information on the website of the University Library in Pula.

• 1802 – Venicefounded at the high command of the Navy
• 1850 – Triestethe entire collection moved from Venice to Trieste
• 1869 – Pulathe library becomes a department of the Hydrographic Office
• 1918with the collapse of Austria-Hungary, the library is taken over by the Italian army
• 1944after Italy's capitulation (1943), the German army takes the entire collection by train to Bohemia
• 1950 – Viennathe collection is returned to Vienna and housed in the War Archives
• 1975 – back to Pulasome 20,000 volumes are given "as a gesture of goodwill" by the Republic of Austria to the Scientific Library (today the University Library)
• 1996/1997move to the Croatian Defenders' Hall (the former Marine-Kasino) and reopening to the public

After the collapse of Austria-Hungary and the Italian military occupation of Pula on 5 November 1918, the Observatory ceased its activities. The instruments and the library were largely moved to Trieste and other Italian cities, and the monument to Admiral Tegetthoff, at whose initiative the Hydrographic Office had been founded, was removed.

The fate of the Observatory mirrored the general stagnation of the town of Pula. The Hydrographic Office was renamed the Italian Royal Hydrographic Institute, with the status of a branch of the central Italian hydrographic institution. Meteorological and geomagnetic observations continued, while astronomical work died out completely.

After the withdrawal of the Italian forces, Anglo-American aircraft bombed Pula on several occasions during 1944. Because the Hydrographic Office and the Observatory were still marked on maps as military installations, Allied bombs razed the building to the ground. Photographs taken during the bombing raids show the Observatory still intact, and then hit directly and destroyed.

The partially preserved section of the north-east wing was restored in 1947/1948 and housed a weather station of the Yugoslav Navy. In 1949 the station was taken over by the newly founded Administration of the Hydrometeorological Service of the Government of the People's Republic of Croatia, today's Croatian Meteorological and Hydrological Service (DHMZ).

The restoration of the Observatory's remains was not entirely successful, mostly for technical reasons. Air temperature, pressure and humidity were measured in an instrument shelter within a fenced enclosure in front of the building, while the heliograph and anemometer were mounted on an auxiliary scaffold on the south side of the dome. Two meteorologists' families moved into the building and continued the observations from Monte Zaro. Meteorological observations are still carried out from the same location today — the DHMZ station on Monte Zaro now has the status of a climatological station.

During the repairs two domes were reconstructed — the classic dome and the meridian dome. The frame of the classic dome that survived the bombing was used to restore its original shape, clad with timber on the inside and galvanised sheet metal on the outside. The mechanism for rotating the hemispherical dome remained usable, as did part of the opening mechanism. The slit, however, was repaired in such a way that observations were possible only up to 30° above the horizon, leaving the largest and best part of the sky out of reach. The blasts during the bombing also distorted the dome itself, so the force needed to turn it depends on the position of the slit. Since the dome was not in use at the time, there was not even any access to it — the stairs led only as far as the terrace.

The interior of the main dome and its original opening and rotating functions have been fully preserved to this day. The axial ball bearing on which the dome rests was cast, at the time the Observatory was built, in the Pula Arsenal, where such bearings were made for the gun turrets of Austro-Hungarian warships. To the best of our knowledge, it is the largest bearing of its kind still in operation.

The meridian dome suffered more severe damage: its mechanism survives in its original form but cannot be used. Only the outer covering was reconstructed to protect the dome from further decay; the gear shafts were bent by the force of the blasts and the chain drives are incomplete, so its restoration is still waiting for better days.

The Astronomical Society "Istra" Pula (ADIP) was founded on 27 December 1973, at a time of great exploratory ventures in astronomy and astronautics, when the thirst for knowledge was hard to quench owing to a lack of literature, resources and organisation. The society's primary mission was to popularise astronomy and the other natural sciences through lectures and observations of celestial phenomena for people of all ages.

Close ties with schools led to a large number of pupils taking astronomy as an elective subject, and in the late 1970s excellent results were achieved in the competitions of the "Nauka mladima" (Science for Youth) movement, organised by the then Narodna tehnika (People's Technology), the forerunner of today's Community of Technical Culture.

Telescopes were not as readily available as they are today — besides high prices, state import restrictions were also a problem. Nevertheless, in 1975 the society raised the funds to buy a "Celestron 8" telescope, which is still in use today. For several months it was displayed in the shop window of "Narodna tehnika", catching the eye of passers-by. In those days observations were held on the rooftop terraces of buildings in the town centre or just outside town — light pollution was far lower than it is today.

1982: the Observatory becomes ADIP's home

In 1982 the Observatory was handed over for use to the Astronomical Society "Istra" Pula, which revived astronomical observations there. The building was in a very dilapidated state, so the members immediately set about refurbishing it — room by room, with the help of local enterprises and a great deal of volunteer work. Because the dome was inaccessible at the time, observations were made from the meadows on Monte Zaro, by the fountain, and partly from the terrace and the meteorological scaffold.

At the society's proposal, on 30 May 1983, by decision no. 435 of the Regional Institute for the Protection of Monuments in Rijeka, the Observatory was declared a cultural monument of category C.

The Observatory brought new momentum: members took up astrophotography, primarily of the Sun, and regular visual observations were made of the Moon, the planets and the major meteor showers (mostly the Perseids and Orionids, as the weather usually prevented observation of the Geminids and Quadrantids). The Observatory also hosted the "Nauka mladima" school competitions, at which each pupil presented, in addition to a written part, a practical project — from observations of meteors, planets or variable stars to studies of the efficiency of solar energy use. The most successful were rewarded with an astronomy camp on the island of Prvić.

Once the restoration was completed, work with young people resumed and the popularisation of astronomy continued through public observing sessions and lectures. The Observatory is visited by many groups of school and university students — sometimes more than a hundred participants at once — who learn about its history and its importance for the development of astronomy worldwide. Alongside the history, younger children also learn the basics of how the bodies of the Solar System move through an interactive presentation.

In 2010 the society received the Charter of the Croatian Community of Technical Culture (HZTK) for its many years of outstanding contribution to the development and promotion of technical culture and astronomy and to the preservation of a cultural monument — the Observatory in Pula.

Young members at the Observatory prepare projects for the astronomy competitions run under the Education and Teacher Training Agency and present them at a joint lecture, with their parents in the audience. Since 2009 the number of pupils taking part in the competitions has risen sharply; every year at least a few of them reach the national competition, where some have even won first place. Members also go out into the field, observing the Sun with the necessary safety precautions and warning of the danger of looking directly at the Sun.

Every year society members take an active part in the Science Festival. In 2016, together with Pula's "Metris", they presented an analysis of the "Križevci" meteorite, in whose recovery the society played a very important role. The society also takes part in joint projects of the Croatian Astronomical Union, such as "Women in Astronomy", and members give talks at amateur astronomers' meetings and related events, always striving to spread knowledge about the history of the Observatory.

The COVID-19 pandemic halted public activities, but meteor observing continued without interruption, and alongside the observations, scientific papers based on our own data are being published. We are especially pleased that a growing number of former young members — today engineers, holders of master's degrees and PhDs — stay in touch with the society and are happy to join in its activities.