DMD-MOS: Overview

A Dual-Channel Approach:

1) An imaging channel used for viewing the telescope field and creating a slit mask to observe the selected targets

2) A spectroscopy channel consisting of a traditional R~1000 spectrograph

Imaging + Spectral Channels

The imaging channel consists of a simple collimator/camera relay to image the DMD surface which is conjugate with the telescope's focus. By using an astrometric solver along with a mapping between the imaging channel and DMD array, we are able to create accurate slit masks for selected science targets and additionally monitor the telescope field for any significant guiding drifts. The spectral channel consists of a volume phase holographic (VPH) grism-based spectrograph covering a range of 400-700 nm. The slit mask created using the imaging channel sends light into this channel to produce the spectra required for scientific observations. This channel also features a calibration subsystem for obtaining spectral flats and arc lamp frames that are used to calibrate and process the data obtained with DMD-MOS.

Optical Layout

Both channels utilize a custom collimator/camera relay to image the DMD slit mask. In the spectral channel, the collimated beam is incident on the VPH grating before it is imaged through the camera lens on to the GSENSE 2020-BSI scientific CMOS sensor housed within a TEC-cooled Ximea xiJ camera.