The spectrograph is to be installed on the field rotator of the
6 m telescope prime focus without a standard field corrector. A CCD chip of 2048x2048
pixels (EEV CCD42-40) developed at SAO RAS is used as the detector.
The optical scheme of the spectrograph relies on home-made types of
glass, all the optics are spherical. The overall dimensions of the prime focus cage and
the necessity of providing a high aperture ratio of the spectrograph at a maximum possible
size of the collimated beam are taken into account. To achieve maximum quantum efficiency
for a wide spectral range all optical surfaces are allowed to be coated by a
untireflecting layers. The optical and ray diagram of the instrument with designations of
main instrument blocks is shown in Fig.1.
The MOUSER is built up from a number of individual units mounted in a
rigid construction with allowance made for it to be installed in the prime focus cage. The
change of the different observational modes of the instrument is performed by turn-over of
the diagonal mirrors, inserting of masks into the focal plane or by change of the
diffraction grating or the mirror within a few minutes.
To compensate for the image tremor at frequences between 0.02 Hz
and 5 Hz, which is caused by the telescope mounting vibration, a special corrector
is proposed. The tilting afocal aplanatic lens incorporated in the MOUSER shifts the image
within a required range at very small tilts. Such a lens also plays the part of the field
corrector, correcting coma and astigmatism of the main mirror and providing flat field in
the entrance focal plane of the spectrograph.
The spectrograph is controlled from the remote HOST computer, connected
through the link interface to an IPC (Industrial Personal Computer) of the spectrograph,
which is equipped by all necessary program drivers and interface cards for performing of
commands, taken from the HOST computer. The HOST PC is provided with specialized software
integrated into the supervising system of the experiment, which enables on-line control of
the spectrograph, CCD detector and telescope.
By the end of 1997 the designing of the spectrograph was basically completed, principal
optical elements and part of mechanical units were manufactured.
V. L. Afanasiev, Eh. B. Gazhur, S. N. Dodonov,
S. V. Markelov, E. I. Perepelitsin
3000; 