Spectrograph SPEM in the Nasmyth focus

Characteristics of the spectrograph

Collimatorf/16, D = 80 mm
Maksutov cameraf/2.5
Diffracting gratings651 and 1200 Grooves/mm (150×150 mm)
Dispersion near Hα line with grating of 651 gr/mm1.76 Å/pixel; 2465 Å per frame
Spectral resolution with the entrance slit width of 3″ and with grating of 651 gr/mm7.5 Å
Scale0.78 arcsec/pixel
Exposure for Seyfert galaxies of 13-14m with grating of 651 gr/mm15-20 minutes (S/N > 100)

Detector - CCD camera SPEC-10 (Roper Scientific, USA)


Readnoise1.50 ADU = 2.98 e-
Gain1.99 e-/ADU
QE95% Max. at λ5500 Å
Geometry1340×100 pixels, 20×20 μm
Well Depth262,000 e-
Dynamic resolution16 bits, 100 kHz
Coolingup to -100°C, regardless of ambient