Photometric camera

This image has an empty alt attribute; its file name is image7.jpg — The primary focus with the CCD camera for optical imaging. Credit: Miroslav Šlechta.

The photometric camera G2-1000BI (Moravian Instruments) with E2V CCD 47-10 chip is installed in the primary focus. The focal length of the main mirror is 9 m (focal ratio f/4.5), but the correcting lens changes the effective focal length in primary focus to 7 m (focal ratio to f/3.5). The automatic exchange of the instruments between spectroscopic (fibers) and photometric (primary focus camera) configuration can be done within 1 minute. The camera is equipped with five position rotating filter wheel with different filters and cooled up electronically (down to -40° C under ambient) by Peltier cell.

Camera and chip

ADC	Resolution	Pixel size	Read. noise	Efficiency	Linearity	Reading
16 bit	1056 x 1027	13 x 13 μm	9 ADU	90% _{(500-700 nm)}	> 95 %	10 s

Camera and telescope

Photometric filters

The camera is equipped with five position rotating filter wheel with different filters. Complete list of available filters: Sloan u’, Sloan g’, Sloan r’, Sloan i’, Sloan z’, H-alpha, [O-III], [S-II], Bessel B, Bessel V, Bessel R, Bessel I. Narrow band filters have bandpass width 3 nm.

Currently installed filters (see the table).

Position	0	1	2	3	4
Filter	N II	i’ (SSDS)	r’ (SSDS)	g’ (SSDS)	u’

Camera and telescope performance (in good seeing conditions)

Brightness	Exposure	Filter	Measurement error	Χ
~ 12.5 mag	8 s	r’	~ 0.002 mag	~ 1,05
~ 15.2 mag	8 s	r’	~ 0.006 mag	~ 1,10
~ 16.2 mag	10 s	g’	~ 0.020 mag	~ 2,20
~ 18.3 mag	20 s	g’	~ 0.030 mag	~ 1,10
~ 23.3 mag	7 h	r’	~ 0.160 mag	~ 1,40

Effective focal length	Field of view	Angular resolution	Test image
7 000 mm	6.3′ x 6.3′	0.385 “/pixel