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Patrol-Telescope for Solar Observation

Telescope Mounting and Tracking

The patrol- or surveillance telescope comprises several refractors on a combined parallactic mounting. It was built at the beginning of the 70´s of the last century and since then it was continuously improved. Originally the tracking was done by 2 pairs of photodiodes in the light path of the Hα-telescope. In perfect alignment they were all exposed equally. If they were not equally lightened a differential signal was generated from which a correction of the hour angle and the declination was obtained. Since the appearance of the 1 MPix CCD camera the tracking is micro processor-contolled out of the calculated current solar position. A cross-check and fine correction is done by the analysis of the solar image position in the focus of this camera.
3D-Model overall view...
3D-Model telescope arrangement...

Continuum for Sunspot Drawings

Refractor d/f = 110/1650 mm with an attached projection device for the draft of sunspot drawings. Due to mirrors in the light path the drawing is side reversed (W is left!). The enlargement of the solar disk to a diameter of about 250 mm corresponds to a magnification factor of about 100.

Continuum for Photoheliogramms

Photosphere Camera (PhoKa), refractor d/f = 130/1950 mm with a band-pass filter at 546 nm with 10 nm FWHM. It is in operation since 1989. The primary focus image is magnified by a projection lens, which has very low distortion, to a diameter of about 87 mm. A B/W film with a size of 13x16 cm is used as a detector. Details in: Pettauer, T.: The Kanzelhöhe Photoheliograph, in The Dynamic Sun, Proceedings of the 6th European Meeting on Solar Physics held in Debrecen, 21-24 May, 1990. Edited by L. Dezso. Publ. of Debrecen Heliophysical Observatory of the Hungarian Academy of Sciences, 7, 62-63, 1990.

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Kanzelhöhe Photosphere Telescope (KPT), Refractor d = 130 mm and an effective focus length f = 1460 mm with a band-pass filter at 546 nm with 10 nm FWHM. Therefore the telescope has a diffraction limit of 0.9 arcseconds, which corresponds to ​​about 700 km on the Sun. That´s about the size of solar granule. The instrument is a reconstruction of the above described telescope for the Photosphere Camera and operational since July 2007. The focus length reduction allowed the implementation of the KPDC system in the primary focus.

Kanzelhöhe Photosphere Digital Camera (KPDC), mit 4 MPix 10bit CCD-Kamera: Since July 2007 a JAI Pulnix TM-4100CL on a Silicon Software ME-III Frame Grabber is in service, the frame rate of about 10 frames/sec allows the application of frame selection for image enhancement. The exposure time of about 2.5 - 25 ms is automatically controlled for constant density. The normal image rate is 1 image/30sec.

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Refractor d/f = 100/2000 mm with a band-pass filter at spectral line Hα (656.3 nm). The Lyotfilter made by Zeiss has a FWHM of about 0.07 nm. As a thermal protection an interference filter with a FWHM of about 10 nm is in the light path. The Lyotfilter can be tuned by turning the polarizers in narrow boundaries with little degradation of the filter characteristics. So also observations in the line wings of the solar Hα line are possible (max. ±0.15 nm). A beam splitter allows the application of two detectors at the same time.
3D-Model optical path...

Analogue System (until 2000)

Film-Cartridge with 35 mm film: It was in service since the beginning of the operation of the telescope in 1975 until 2000. One cartridge contained about 45 m 35mm B/W-film (24x36 mm), i.e. about 1000 exposures. Altogether a sum of 515 films was exposed. Under normal conditions 1 picture every 4 min. was taken. Several times a day double exposed images were taken for illustration of prominences. An electronic controlled shutter exposed the film for about 0.02 to 1 sec.
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High Cadence Hα Imaging System (until 21.09.2010)

1 MPix 8bit CCD-Camera: Since 1997 until mid of July 2005 a Pulnix TM-1001 on a Dipix XPG-1000 frame grabber was in service. The frame rate of about 15 frames per sec. allowed the application of frame selection for image enhancement. The exposure time of about 2.5 - 25 ms was automatically controlled for equal density. Until the beginning of 2000 every day only a few images were taken. Since 2000 every min. a image was taken, during flares the sequence was increased to 5 pictures per min.

1 MPix 10bit CCD-Camera: In mid of July 2005 a Pulnix TM-1010 on a Coreco PC-DIG frame grabber and a new comfortable software replaced the old 1 MPix 8 bit CCD-camera. Apart from the higher dynamic range, which made it necessary to regard the dark current, all other parameters remain unchanged. Since mid of August 2014 a Pulnix TM-4200GE 12bit camera with Gigabit Ethernet interface is in use.

High Resolution Hα Imaging System

4 MPix 14bit CCD-Camera: With the use of Apogee KX-4 on an Apogee PC-ISA interface card instead of the film cartridge Kanzelhöhe Observatory became a base station of the Global Hα Network. The rate of images was 1 /min at a fixed exposure time of 30 ms. Because of the mechanical shutter and the slow read-out of the camera frame selection wasn´t possible. Dark current frames were taken daily; Flatfields (Kuhn-Lin method) only at bright sky once a day.

4 MPix 12bit CCD-Camera: Since mid of January 2008 a Pulnix TM-4200GE with Gigabit Ethernet interface replaces the Apogee KX-4. A frame rate of 7 frames/sec permits again the application of frame selection to benefit from moments of good seeing, the exposure time is considerably shorter (from ca. 4 - 25 ms) and is controlled automatically in oder to achieve evenly exposed image series. The image acquisition rate is 10 img/min during high solar acitivity and 1 img/min in standard mode. Dark current frames are recorded daily, the flat field is much more uniform than with the Apogee KX-4, so that we do not obtain flat field frames (Method Kuhn-Lin) normally.

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Calcium II K -Telescope

Refractor d/f = 110/1650 mm with a band-pass filter at spectral line Ca II K (393.4 nm). Do detect the whole solar disc on the CCD chip we insert a second lens within the focal length of the objective lens. Therefore, we reduce the effective focal length from 1650 mm to 1500 mm. The Ca II K interference filter made by Lunt has a designed FWHM of about 0.2 nm. Due to the inclination of the light beam (f/15) the FWHM is broadened, with a real FWHM of 0.3 nm. In front of the Ca filter there are additionally two interference filters for reducing the head.

4 MPix 12bit CCD-Camera:Since the end of July 2010 a Pulnix TM-4200GE with Gigabit Ethernet interface is in operation for taking Ca II K-Images. A frame rate of 7 frames/sec permits the use of frame selection to benefit from moments of good seeing, the exposure time is in an area from approx. 1 - 25 ms and is controlled automatically in order to achieve evenly exposed image series. The large range of the exposure time is caused by Rayleigh scattering in the Earth's atmosphere. Due to this fact, the atmospheric transmission depends on the solar altitude and the wavelength, and the Ca II K transmission through the earth atmosphere is not constant over the observation day. The standard image acquisition rate is 1 img/min, in times of high solar activity 10 imgs/min are taken. Dark current frames are recorded two times per day, before and after the observation period. We do not take flat field frames, because the flat field is very uniform as it is in the other operating cameras.

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A small spectrograph in the cellar laboratory is used to measure the central wavelength and bandwidth of filters, which are then installed at the telescope.

Data archive - CESAR

Soon after the implementation of digital image acquisition systems the development of an integrated data management and archiving system started. CESAR connects with LAN technology data and image acquisition systems (like sensors, or CCD-camera with frame grabbers and their hosts) with process- and archiving servers and mass storages like RAID- hard disk systems, streamer or CD/DVD- drives. It supports the observer via an intranet portal with online forms for data input and data control of the automated observations.

» Archive ...

UV-B Network Austria

Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management has launched a project to monitor UV radiation. One of these monitor stations is Kanzelhöhe. Sensors comprehend not only a broad band instrument for determining global radiation and a filter instrument, which spectral resolution is tuned on the erythem effect function of the skin, but also instruments fo retrieve electronically meteorological parameters such as air temperature, relative humidity as well as sunshine duration.

Solar Irradiation

For a broad-band recording of the solar irradiation at the surface radiometers for UV-A and UV-B, as well as for the photosynthetic active radiation and further pyranometers are operated continuously at a platform on top of the observatory building.

MetCam Weather Camera System

On request of the Central Institute for Meteorology and Geodynamics a camera system for support of the visual weather observations was developed. A rotor for a commercial webcam was constructed, which is controlled by the camera. Today there are three camera systems in operation at exposed locations in Carinthia. The software package CamVis was also developed at Kanzelhöhe Observatory for this camera system. This software allows the visualization of panorama and time series of weather cameras and also of other graphical resources for weather analysis.
The recent weather panorama at Kanzelhöhe is shown on the lower part of homepage of the observatory.

Semi Automatic Weather Station

The air temperature and the humidity in a height of 2 m, the surface temperatur in a height of 5 cm, the ground temperature in 10, 20, and 50 cm depth, the sunshine duration with a Campbell-Stokes sunshine-autograph and a Solar 111 - Haenni, the precipitation and the snow height as well as wind speed and direction are measured automatically. Beyond that, personal measurements of the rain, snow height and the amount of fresh snow are performed. The observation duty includes also the weather observation at regular times. The observations are executed at the vicinity of the observatory in cooperation with the Central Institute for Meteorology and Geodynamics.


How many stars can be seen by naked eye? Every night artificial light sources brighten the night sky and make the stars invisible - that is not necessary, it can be prevented! There are simple techniques, which can bring back the glow of the Milkyway above our cities. This goal should be reached until 2030 - the recipe is simple: Use decent light, where light is needed! The lightmeter measures the brightness of the night sky, the data is stored centrally together with the data of other lightmeters in Austria and surroundings.