The telescope

SALT Telescope is located in South African Astronomical Observatory (http://www.saao.ac.za) on Karoo plateau about 370 km north of Cape Town. The Observatory is located at an altitude of 1759 m above sea level.

The telescope is owned by an international consortium. Poland has a 10% of the observing time on SALT. Our participation in the project has been financed by the Committee for Scientific Research and the "Foundation for the SALT Telescope in Poland".

SALT is an improved version of the innovative HET telescope that works for a few years at McDonald Observatory in Texas (http://www.as.utexas.edu/mcdonald/het/het.html). The telescope has only one degree of freedom azimuthally rotating at a constant zenith distance of 37 degrees (latitude of SAAO is 32°23' South).

The main mirror is spherical in shape and consists of a mosaic of 91 hexagons with a side of 1 m. The focusing surface corresponds to a single circular mirror of diameter of about 10.5 meters. During the observation telescope remains stationary and a moving image of the sky above the main mirror is followed by a moving "tracker" on the surface of the focal plane. Tracker is equipped with a spherical aberration corrector and differential atmospheric diffraction corrector. At a given position of the telescope observations are possible in the sky belt of width of 12 degrees. As a result, areas of sky at declinations +10 < δ < -75 deg are available for the observations. The maximum time of observations of a given object during the night is from 45 to 150 minutes, depending on its declination. The effective collecting area changes during the observation. In extreme cases it can fall the area corresponding to the circular mirror with a diameter of 8 m. The variable effective area limits the absolute calibration of the photometry and spectrophotometry.

The diameter of the telescope's field of view is 8 arcminutes. According to the specification of the optics is to give images of EE(50) not worse than 0.6 arcsec (in the absence of atmospheric disturbances, not less than 50% of the light spot of the object would be concentrated in a disc with a radius of 0.6 arcsec). Median seeingu the SAAO is 0.9 arcsec, so the typical conditions of observation images of the stars will have profiles with FWHM of 1 arsec.

Currently we have the following instruments available on SALT:

• RSS spectrograph (PFIS)
• SALTICAM camera
• micro-channel plate BVIT
• HRS spectrograph

The observations are carried out in the queuing mode. This means that programs eligible for execution are to be performed entirety by the staff of SALT, without the participation of the authors of the project. The investigators receive a set of data (also preprocessed) after their completion. There is a possibility of remote access to the fragmentary observations within a given program.

A lot of useful information related to the telescope and its instruments can be found in the SALT home page http://www.salt.ac.za.