Fabrication of the MORISOT spectrograph begins

08 Oct 2018 - Frederic Hessman

The new low-resolution, fibre-fed IFU “COLORS” (“COmmerical Lens Optical Reflection-grating Spectrograph”) spectrograph for MONET/South, is now being fabricated in Göttingen’s mechanical workshop. Here is an exploded CAD-view of the internal design, showing (in optical order from upper left to upper right to lower left) the fibre-feed, the shutter, a commercial collimator lens, the reflection grating, the commercial camera lens, and the CCD camera.


With a spectral resolution between R=600 (sky in two 200mu “bucket” fibres) and R=1500 (IFU with 31 80mu fibres), the MORISOT system of spectrograph, fibre-feed (behind the filter wheel of the science camera), and autoguider (science camera) will make it possible to perform robotic spectroscopy projects - e.g. monitoring the changing spectra of AGNs, young stars, accreting binary stars, or identifying the character of an object found in a photometric survey (where one usually just has a brightness in several different colours). Schools will be able to study the differences in spectra of stars and bright galaxies and even measure the expansion of the Universe! The IFU (“integral fibre unit”) is a compact hexagonal bundle of 31 fibres that produces a spectral image of a small region on the sky - handy for viewing the differences in the spectra of extended objects like nebulae and galaxies.

The spectrograph, a Masters project by Maksim Tkachenko (HAWK Göttingen), will be installed on MONET/South sometime in 2019.