Focal Reducer - Optical Slit Spectrograph

 

Front view

A Focal Reducer is  mounted to the 1.3m telescope. The Focal Reducer can be used in two different configurations:

1. In the imaging mode the focal length of the telescope is reduced by a factor of 1.87, enlarging by the same factor the imaged area of the sky on the CCD. A Filter Wheel with 6 filter positions is integrated to the Focal Reducer.

2. In the spectroscopy mode a reflection grating is introduced in the collimator path. Using different gratings, resolutions ranging from 0.57Å/pixel to 4Å/pixel are achievable with a 15μm pixel CCD camera. A Slit Wheel offering 6 positions with slit widths: 80μm, 160μm, 320μm and 640μm is part of this configuration.


A 2k x 0.8k CCD camera is attached to the slit spectrograph. More detailed information is available here.

Side view

 

Spectroscopic calibration


Maps of the calibration lamps


 

Gratings for the Focal Reducer

Lines/mm

Blaze

Wavelength (nm)

Wavelength in 1st order

for max. Intensity

Dispersion (Å/mm) Mounted
3600 250 231 25.41 No
2400 430 397.3 37.8 Yes
1302 550 508.1 70.44 Yes
1302 480 443.5 70.27 Yes
1200 700 646.7 76.39 Yes
651 530 489.7 137.6 Yes
600 750 692.9 150.8 Yes
600 500 461.9 148.4 Yes
325.5 550 508.1 269.0 No
325.5 430 397.3 267.3 Yes
162.75 500 461.9 529.1 No