Open days of the Hvar Observatory and Science Festival 2026
Last Updated on Tuesday, 31 March 2026 11:55 Written by Jaša Čalogović Thursday, 12 February 2026 07:00
We are organizing open days of the Hvar Observatory from 20 to 25 April 2026 on the occasion of the Science Festival 2026 with the theme "Energy". In the period from 20 to 24 April 2026, small groups of children and pupils will have the opportunity to visit the Observatory on Hvar, see telescopes, observe the Sun and participate in demonstrations prepared by the staff of the Hvar Observatory. On Saturday, 25 April, the Observatory will also be open to the public from 10:00 to 16:00 h. In addition, the staff will also organize public night sky observations in Hvar.The Hvar Observatory is the only observatory in Croatia fully dedicated to professional astrophysics and is not open to the general public. On the occasion of the Science Festival, we open our doors to small groups for guided tours of the observatory, telescope viewing, solar observation, and demonstrations. The program is conducted under the expert guidance of scientists and staff of the Hvar Observatory. Through demonstrations by our employees, you will learn how sunlight is actually composed of different colors, how the Sun is essentially a giant magnet, what solar storms are, and what comets are and where their tails come from. Our aim is to bring science closer to children and the general public, especially astronomy, which is often neglected in regular education. Please note that the Hvar Observatory is not able to organize transportation to the observatory.
Leaders: Dr. Filip Matković, Dr. Jaša Čalogović, Dr. Mateja Dumbović, Toni Visković, BSc Geod., Akshay Kumar Remeshan, MSc Phys., Melike Tirnakci, MSc Space Sci. & Tech.
Program
Organized tours for children (arrival must be announced in advance via mail This e-mail address is being protected from spambots. You need JavaScript enabled to view it )Monday – Friday, 20 - 24 April 2026: 09:00 – 12:00 or 13:00 – 15:00 h
Open day (for general public, no prior registration required):
Saturday, 25 April 2026: 10:00 – 16:00 h
Night sky observation
Hvar, park in front of the City Loggia, 23 April 2026: 20:30 - 22:00 h
Note: In case of unfavorable weather conditions on the above-mentioned day, a new date for night sky observation will be announced here.
About Hvar Observatory
The Hvar Observatory is a special organizational unit of the Faculty of Geodesy at the University of Zagreb, dedicated to scientific research in the field of astrophysics. It is equipped with telescopes for observing stars and the Sun, whose domes are located above the town of Hvar within a historic fortress built during the Napoleonic Wars.
The Observatory was founded in 1972 through the joint efforts of the Council for Science of the Socialist Republic of Croatia and the Astronomical Institute of the Czechoslovak Academy of Sciences in Ondřejov. The co-founder of the Observatory, the Faculty of Geodesy of the University of Zagreb, manages the use and finances of the Hvar Observatory. The Observatory is situated in the southwestern part of the island of Hvar, above the town of Hvar, on a steep hill at an elevation of 240 meters, within the historic Napoljun Fortress, built by the French army during the Napoleonic Wars at the beginning of the 19th century. From the Observatory there is a beautiful view of the town of Hvar, and it is surrounded by low Mediterranean vegetation that gradually transitions into a pine forest at the foot of the hill.
Telescopes of the Hvar Observatory
The solar double telescope was installed on Hvar in 1972. It consists of two refractors mounted on a parallactic mount. The first refractor, with an objective diameter of 217 mm (f/11), is used for observing the photosphere and is equipped with a white-light filter. The second refractor, with an objective diameter of 130 mm (f/15), is used for observing the chromosphere and is equipped with an H-alpha filter. The telescope is intended for detailed monitoring of rapid solar chromospheric and photospheric phenomena, such as solar flares. It is equipped with CCD cameras and, using a field of view of 7 and 11 arcminutes, allows high-resolution imaging of active regions on the Sun, serving as a complement to full-disk solar patrol observations (Kanzelhöhe Observatory).
The 650 mm reflector telescope, equipped with a photometer, is most commonly used for studying variable stars. It is a Cassegrain-type telescope with a 300 mm secondary mirror and a focal length of 7280 mm (f/11), mounted on a parallactic mount. It was built at the Ondřejov Observatory of the Czech Academy of Sciences for photometric observations and was delivered to Hvar at the beginning of 1972. Immediately after the telescope was installed, a UBV photometric program for monitoring variable stars was initiated, which continues to this day. This program was designed as a complement to the spectroscopic observations of Be stars at the Ondrejov Observatory.
It is the largest and newest telescope at the Hvar Observatory. The Austro-Croatian Telescope was installed on Hvar in 1998. The telescope is of the Ritchey-Chrétien type with a primary mirror diameter of 1060 mm and is mounted on an English mount. It can be used with two secondary mirrors: one with a diameter of 400 mm, providing a focal ratio of f/6.8, and another with a diameter of 260 mm, providing a focal ratio of f/15. Targeting the desired object and controlling the telescope’s drive are performed via computer. The telescope is equipped with a CCD photometric camera and is used for observing open clusters and variable stars.
About Science festival
The Science Festival is an event held in multiple cities across Croatia, aimed at bringing science closer to the public, informing people about activities and results in the field of science, improving the public perception of scientists, and motivating young people to explore and acquire new knowledge. Through a series of engaging activities on a chosen theme (public popular lectures, workshops for primary and secondary schools, science cafés, panels, exhibitions, performances), the festival seeks to present science in a popular, cheerful, and easily understandable way. Admission to all events is free.