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Zeiss-1000 telescope instrumentation and methods


CCD photometer

One of the principal devices used in observations at the telescope Zeiss-1000 is a CCD photometer. This device was put into operation in March 1994. 46% of the observational programs of the second half of this year were fulfilled using this equipment.

The photometer was built using the standard set of astronomical image recording system based on a CCD of 530 X 580 pixels. The photometer incorporates: automatic remote control; a set of 8 filters; fast shutter that allows short exposures up to milliseconds; internal standard light sources forming a "flat field".

The system of data acquisition is realized in two versions:

  1. the version in the operational system MS DOS with the observation process control and data processing based on the PC VISTA system packages;
  2. the version in the operational medium UNIX (Linux) on the basis of the MIDAS system packages.

The field of view of the photometer is 143 X 212". The scale in the field without the reducer is 15.27"/mm, the element size is 0.275 X 0.366".

The photometer has 5 wide-band and 3 narrow-band filters. The wide-band filters in combination with a CCD of type K585 realize the system similar to the Cousins one.

The central wavelengths of the narrow-band interference filters are designed for the lines [OIII] 5007, H 6563, [SII] 6734 when working in a parallel beam, all the filters have a width at a half of maximum of about 85 .

The count rates (electron per second) for ADU = 1e- computed throughout the image for U = B = R = I = 20.0 for an object observed at air mass equal to 1.0 with the given version of CCD at the telescope Zeiss-1000 are presented in Table 1.

Table 1: Quantum efficiency and count rate in the broad-band system of the CCD photometer of the telescope Zeiss-1000.
Band U B V R I
Count rate (e-/s) 0.18 10.8 12.4 15.7 6.0
Flux at the upper boundary of the atmosphere, (ph/s) 30 120 75 66 38
Extinction coefficient, (magnitude/air mass) 0.62 0.32 0.18 0.11 0.07
Quantum efficiency CCD+filters+telescope, (%) 1.1 12.0 19.4 26.4 16.9
Zero point, A0 V, zenith e-/ADU = 1, (magnitude) 18.14 22.58 22.73 22.99 21.95

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Last update: 29/02/2012