Six dispersers are avilable for use with COSMOS. The properties of dispersers are listed in the table below.
3 pixel (0.9") slit
|Blue (b2k)||1172||500nm||24004||3480 - 6190||0.66||NA|
|3795 - 6615||0.69||NA|
|4150 - 7050||0.71||GG-395|
|Red (r2k)||842||800nm||23005||4985 - 9040||0.99||GG-455|
|5515 - 9635||1.00||OG-530|
|6080 - 10250||1.02||OG-570|
|High-Res Blue (hb4k)||1886||480nm||40004||3770 - 5450||0.41||NA|
|4000 - 5695||0.41||NA|
|4230 - 5950||0.42||NA|
High-Res Red (hr4k)
(OUT OF SERVICE)
1 COSMOS can hold up to five dispersers at a time. The number of dispersers that can be used during a night is limited by the time available for afternoon calibrations.
2The wavelength ranges given for each disperser correspond to the blue, center, and red slits respectively.
3 The dispersion given for each disperser corresponds to the blue, center, and red slits respectively. The dispersions were found by using the IRAF tasks "identify" and "reidentify" along the dispersion and spatial axes. The resulting surface was fit as a polynomial using "fitcoords" and then linearized using "transform" in the "twodspec" package.
4 At 5000Å….
5 At 7000Å….
6 At 6000Å….
7 The COSMOS optics are transmissive down to 3600Å…. There is little value in using this grism with either the blue or center slits.
8 This grism and slit combination can be affected by 2nd-order blue light from 3600Å… - 3700Å… appearing between 7200Å… - 7400Å… if the GG-395 blocking filter is not used. If this filter is used, light below 3950Å… will not be transmitted.
9 At 8000Å….