SCORPIO
Spectral Camera with Optical Reducer for Photometrical and
InterferometricalObservations
SCORPIO is a multi-mode focal reducer of the BTA. It it used for observations of
star-like and extended objects in following observational modes at the prime focus
(F/4) of the 6m telescope:



Broad-, medium- and narrow-band direct imaging
Long-slit spectroscopy
Slitless spectroscopy
The optical part contains of the collimator (F/2.2) and the camera (F/1.8). The total
focal ratio it the prime focus of the telescope is (F/2.6). The optics of the reducer
compensate for the aberrations of the main mirror of the telescope, all optical
surfaces have antireflecting coating in a spectral range 3500-10000 A. SCORPIO has
two filter's wheels for interferometric narrow-band and middle-band filters (Wheel 1
in the focal plane) and for broad-band filters (Wheel 2 between the field lens and the
collimator). The dispersers (grisms or Queensgate IFPs ET-50) installed between the
collimator and the camera where the exit pupil of the optical system is located. The
diameter of the collimated beam is 35mm.
Collimator f.
Beam size
Camera f.
Field
Scale
slit width
slit length
Detector
146mm
37.5mm
106mm
11x11 arcmin
0.67 arcsec/pix
2 arcsec
6 arcmin
TK 1024
Focal reducer main parameters
Focal reducer main parameters
Focal ratio at the 6m telescope
F/2.6
Spectral Range
3600-10000 A
80% in Direct Image mode
DQE (telescope+SCORPIO+CCD)
30% in Long Slit mode
20% in Fabry-Perot mode
Limit magnitude for images
R=23.8 (S/N=5 for Texp=1800 sec, seeing 1.5'')
Limit magnitude for low-resol. spectra
R=19.0 (S/N=10 in continuum, Texp=3600 sec)
CCD-Detector
Name
TK 1024
Size, pixels
1024x1024
Scale, arcsec/px
0.67
Field of view, arcmin
11
Pixel size, mkm
24x24
Quantum Eff. Max
80%
Read-of-noise, e
3.0
Gain, e/ADU
1.1
Dark, e/min
0.1
0.8
0.6
DQE
0.4
0.2
3000
4000
5000
6000
7000
8000
9000
wevelength (A)
Fig. Differential Quantum Efficiency of TK 1024 CCD
Filters
Name
U (Johnson)
B (Johnson)
V (Johnson)
Rc (Cousins)
Ic (Cousins)
H
[SII]
Tmax(%)
25
41
49
53
38
70
75
10000
Glass filters for Jounson-Cousins photometric system. Diameter - 70 mm. Thickness 6 mm
SCORPIO grisms
name
Lines/mm
Spectral range, A
FWHM, A
GR300
GR600
VPHG1200R
VPHG1800R
300
600
1200
1800
3400-10000
4200-6680
5800-6900
5900-6800
20
10
5
3
Dispersion,
A/pix
6
3
1.4
0.8