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The G1-2000 CCD camera used by observatory in Valasske Mezirici to capture the Sun
 The observatory in Valasske Mezirici is focused to long term observations of solar activity in both photosphere (in visible light) as well as in chromosphere (in the H-alpha spectral line). The first image of solar photosphere was captured in this observatory on September 1957. This date also marks the beginning of creation of solar photographic archive. The program was later extended to detailed observation of sunspots and active regions in the solar photosphere (on May 1979). Observations of solar prominences in the H-alpha spectral line began on June 1970. Systematical observations of solar prominences were the main focus of the observatory in the last decade of the previous century.

The digital age at Valasske Mezirici followed the first tests in 1999, when regular observations using CCD TV camera Oscar on the coronograph telescope started. Data were stored as individual frames or as short video sequences on the computer or the video sequence was recorded on standard VCR. The new telescope, capable to observe the solar chromosphere, was introduced into observations in 2001. Images from this telescope were also captured by the Oscar camera, but later this observation program was chosen as a first application of modern digital CCD camera G1-2000 in Valasske Mezirici Observatory.

The G1-2000 camera on chromospherical telescope in Valasske Mezirici Observatory

The G1-2000 camera on chromospherical telescope in Valasske Mezirici Observatory

The G1-2000 CCD camera on the chromospherical telescope (135/2350 mm, effective focal length 5170 mm, H-alpha filter DayStar 0,7) offers field of view approx. 4.7' on the longer side of the detector. Theoretical resolution of this setup, determined by the telescope itself, is 0,8 per pixel.

The quality of our observations is highly affected by the atmospheric seeing. High download rate together with very short exposure times around 0.001 allows us to select images acquired in moments with good seeing conditions, which significantly enhances the whole setup performance.

Test observations are under way at Valasske Mezirici Observatory from February 2008. Currently the best images of the solar chromosphere were captured on March 31st, 2008, when some active regions accompanied with sunspots appeared on the Sun after a long period of quiet Sun.

Active regions NOAA 10987 (left) and NOAA 10988 (right)

The images above contain surroundings of sunspots and structures in chromosphere in the active regions marked NOAA 10987 and NOAA 10988. Such observations should allow us to systematically monitor changes in morphology of active regions, which are connected with their development and also with solar flares.

We plan to use the another G1-2000 cameras also on the solar coronograph for monitoring of solar prominences.

Jiri Srba, Valasske Mezirici Observatory (

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