TELESCOPE INFORMATION
 

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Vacuum Tower Telescope
Location: Observatorio del Teide, Tenerife, Spain
Property: Kiepenheuer-Institut für Sonnenphysik - KIS
Operated by: Kiepenheuer-Institut für Sonnenphysik - KIS
Operative since: 1989
Phone: +49-761-3198-0 Fax: +49-761-3198-111
Email: secr@kis.uni-freiburg.de Web Page: http://www.kis.uni-freiburg.de
Full address: Kiepenheuer-Institut für Sonnenphysik,
Schöneckstr. 6
79104 Freiburg
Germany
Description: GENERAL DESCRIPTION
The VTT is operated by four German institutes: the Astrophysikalisches Institut Potsdam, the Kiepenheuer-Institut für Sonnenphysik (Freiburg, chair), the Max-Planck-Institut für Sonnensystemforschung (Lindau), and the Universitäts-Sternwarte Göttingen. The telescope is used for scientific observations from mid April through mid December. Typically 25 observing campaigns of 9 days each are carried out every year.

INSTRUMENTS
The VTT is a classical solar telescope: two coelostat mirrors at the top feed the sunlight into the telescope which spans 10 floors. The primary mirror has a diameter of 70 cm and a focal length of 46 m. The main advantage of the coelostat system is the non-rotating solar image in the laboratory. The VTT offers several spacious optical laboratories for all kinds of optical setups. Some of the laboratories are used for permanent installations, but there is always room for specialized or dedicated instruments. Since 1998 an adaptive-optics system has been developed at the KIS. The main components of the system are a Shack-Hartmann wavefront sensor with 36 sub-apertures, a deformable mirror and a high-speed digital camera. A closed-loop bandwidth of about 130 Hz is achieved. Since 2003, the AO system is permantly installed and available to all focal plane instruments.

For the OPTICON/ACCESS program we support the instruments: (a) POLIS, (b) TIP, (c) TESOS, and (d) the Echelle Spectrograph. Some of the instruments can be used in parallel, e.g., POLIS & TIP or TESOS & TIP. (a) POLIS is a spectropolarimeter for the iron line pair at 630.2 nm with simultaneous intensity profiles for Ca II H. It is ideally suited to study the photospheric magnetic fields and the chromospheric wavelength-dependent emission. (b) TIP is a spectropolarimeter for the near Infrared (up to 2 micrometer). Of special interest are the 2 iron lines at 1.5 micrometer for magnetic and velocity fields in the deep photosphere and the He line at 1083.0 nm for chromospheric magnetic fields. (c) TESOS is a 2D spectrometer based on three Fabry-Perot-Interferometers achieving a spectral resolution of 250000, being able to scan a specral line in less than 30 s. TESOS can also be used in a polarimetric mode to measure I, Q, U, and V. (d) The Echelle spectrograph allows to measure the line intensity profiles of up to three different optical wavelength ranges.

SCIENTIFIC HIGHLIGHTS
The VTT instrumentation is designed for high-quality measurements of plasma flows and magnetic fields. Some instruments can be combined for simultaneous observations in different parts of the solar spectrum, from the near infrared to the near UV. This possibility is a unique feature for a solar telescope and allows to reveal the three-dimensional structure of the solar atmosphere. With the help of adaptive optics and suitable image reconstruction techniques it is now possible to observe physical properties of small-scale objects on the solar surface with sizes of only 150 km, at the theoretical limit of the telescope.

PROPOSALS:

Proposal deadline is January 15th, e.g. 15 Januar 2008 for the observing season 2008. The observing season is typically from april to december.
Further details: http://www.kis.uni-freiburg.de/fileadmin/user_upload/kis/projekte/opticon/instrumentation_vtt.pdf
More information: http://www.kis.uni-freiburg.de/index.php?id=64&L=1
Funding sources: State Government of Baden-Württemberg, Federal Government Germany, States with participating Institutes / Universities (Branden-burg, Niedersachsen), Max-Planck-Society
Contact Person:
Name: Schlichenmaier, Rolf Role/Function: Scientist
Email: schliche@kis.uni-freiburg.de Phone: +49 0761 3198-212
Fax: +49 0761 3198-211  Institution: Kiepenheuer-Institut fuer Sonnenphysik
Full Address: Schoeneckstr. 6
D-79104 Freiburg
 

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