Characteristics of the ASIS instrument
The ASIS instrument is made of two parts, a collecting part on one hand and a spectrograph and CCD camera on the other hand, the two parts being connected by an optical fiber.
The collecting part
The collecting part is made of a guiding lens with a 60 mm diameter and a focal length of 248 mm. The Field-of-View was measured at the B.RCLab and is approximately 4.5°. At the end of the guiding lens, a reflective collimator is attached to inject the light into an optical fiber. The guiding lens is pointing field-aligned.
The optical fiber
The optical fiber is provided by SEDI. It has a 600 microns diameter and is connected to the guiding lens via the reflective collimator.
The spectrograph
The spectrograph is a SR303-i Czerny-Turner from ANDOR with an adjustable slit with a width between 10 microns and 2.5 mm. There are 3 gratings with 300, 600 and 1800 lines/mm. They can be selected using a turret.
The optical fiber is inserted into the spectrograph using a dedicated matcher.
The matcher has a 45° plane mirror and a parabolic mirror which allow the user to focus the spot onto the slit entrance of the spectrograph.
A 16 bit iDUS CCD camera from ANDOR is connected to the spectrograph and is cooled down to -70°C using a Peltier. The detector has 1024 x 256 pixels.
