Astronomical and geophysical observatory in Modra, Slovakia

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Info about the observatory


Astronomical observatory
P.O.Box 4
900 01 Modra
tel.: +421 336475261


17°,27402056 E


48°,37327278 N


531.10 m

MPC code:



AMOS (All-Sky Meteor Orbit System) consists of fish-eye lens, image intensifier, projected lens and digital video camera. The  optical system is protected by an outer and inner housing and set of detectors for temperature (inside, outside), air humidity and sky illumination.  The system is designed for meteor observation, but could be used for meteorological, geophysical, aviation or satellite observations. The operation of cameras is automated and remotely controlled.

Field of view of AMOS camera in Slovakia.

Technical specifications

AMOS system is 100 cm tall and 45 cm wide when closed. When opened, the wings of the enclosure have a maximum span of 180cm. Total weight of the system is 30 kg. System is typically placed 20-50 cm above the ground or roof, to allow air circulation for cooling. AMOS was tested in a wind tunnel and can withstand a wind up to 120 mph (190 km/h). The power consumption of AMOS is 30-70 W (24V electric cord). High-speed internet connection is desirable. Technical details can be previewed here.

AMOS enclosure in opened configuration, showing the internal optical system.

AMOS in opened configuration with dimensions after its installation at La Palma, Canary Islands. Pavol Zigo, Jaroslav Šimon and Juraj Tóth (left to right)

AMOS attached to a console mounted to a side wall above the roof in Tenerife, Canary Islands. Cable for electricity and internet is visible on the bottom of AMOS.


The internal part of system is portable (weight of 6.5 kg, size 50 x 25 cm) and suitable for remote expeditions from the ground or air.


The field of view of the AMOS is 180°x140° and the output digital resolution is 1600x1200 pixels with video frame rate of 20/second. Limiting sensitivity is comparable to human eye (+5.5 mag. stellar objects, +4 mag. for meteors and other moving targets). Detection efficiency is described in this document.

The first prototype has been working at the AGO Modra Observatory since 2007, since then 3 more cameras operate in Slovakia, 2 in Canary Islands, 2 in Chile and more are planned in so-called AMOS Video Meteor Network. Each AMOS camera records about 10,000-20,000 meteors per year depending on location and observing conditions as well as about 50 transient luminous events (sprites, elves). A pair of stations detects 5,000-8,000 common meteors, depending on mutual distance of the stations and observing conditions.

AMOS in Slovakia (Modra), Canary Islands (Roque de los Muchachos, Teide) and in Chile.

The astrometric precision of the all-sky system is 0.03-0.05 degrees which translates to accuracy of tens of meters for meteor atmospheric trajectory precision for a meteor at a distance of several hundred km. The post-processing precision of AMOS meteors is larger after all-sky astrometric reduction methods are applied.

Meteor spectra

AMOS cameras can be equipped with diffraction grating for spectroscopy. The spectroscopic version of AMOS cam is called AMOS-Spec. The field of view is circular with diameter of 140°, which is the largest field of view meteor spectrograph. The spectral range is in 350 - 900 nm and the spectral resolution is 2.4 nm/pixel. When operating both AMOS and AMOS-Spec at the same location, the obtained meteor spectra can be linked to the heliocentric orbit of the meteoroid.

Spectrum of the meteor in the video frame (top) and SNR spectrogram of the same meteor (bottom).


Patent pending (Registered SR PUV 78-2013). AMOS was awarded at Invento Prague 2013 by Golden Medal.

Principal Investigator: Juraj Tóth

Co-Investigators: Pavol Zigo, Dušan Kalmančok

Grant support: APVV-0517-12, Slovak Research and Development Agency.

Host Institution: Comenius University in Bratislava, Slovakia



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