3D-printed optical instrumentation: practical starter designs and initial experiences

The Liverpool Telescope group have been designing astronomical instruments for the LT and other 2-4m class telescopes for a number of years. This paper covers a variety of issues which need to be addressed in order to benefit from the unique advantages of 3D printing. In particular we discuss our experience of designing, building and testing a simple prototype structure that is analagous to a simple reflecting grating spectrograph.