Astrograph for the Southern Hemisphere

Optical Sistem: Newtonian Reflector
Manufacturer: Centurion (model C-18)
Mount: Fork-type

Main Optical Data

Primary mirror diameter:450 mm
Focal Ratio:2.8
Effective focal length:1260 mm

Other Data

This instrument is installed at the Burek mountain under an agreement between the Astrophysics Institute of Andalucía (IAA) and CASLEO, and can be operated remotely through the Internet.

The instrument has a 11000M CCD SBIG detector in primary focus, with a 4008 x 2672 pixels matrix, which cover an area in the sky of 1.77 square degrees (97.8' x 65.2'). At the moment, the instrument is equipped with a filter called Luminance, which is centered at 550 nm and is 300 nm wide. This set-up is currently being used for the telescope's main program.

The typical specifications of the chip, which allow autoguiding, are listed in the following Table.

Specifications of the SBIG 11000M
rows × columns4008 × 2672
pixel size9 × 9 µ
chip size36 mm × 24.7 mm
gain0.80 e-/ADU
readout noise<11 e-
dark current<1.5 e-/seg/pixel at 0 °C
A/D conversor 16 bits
coolerPeltier 2 stages -50 °C from ambient
full frame download 26 sec

Approximate limiting magnitude is 20.5 for 120 seconds of exposure and 21.0 for 180 seconds of exposure.

As it is necessary to protect the telescope from the wind, the walls of the shelter where it is located are high enough to allow its operation even in conditions of strong winds. Therefore, the area of the sky available is only 35 – 45 degrees of zenith distance.

There are no tracking problems given the CCD has possibility of automatic guiding over certain field stars; however, this feature is only available when the telescope is operating under the control of a script.

The roof of the shelter, the telescope and the CCD are remotely controlled from any PC connected to the Internet by means of VNC or Remote Administrator. To facilitate the control of the instrument a WebCam is available inside the shelter, which is also remotely controlled.

The control scripts are text files which contain the instructions and commands on exposure, filter, darks, centers to be acquired, etc. Check with the person in charge about the structure of these files.