instrument picture gallery

A large number of photographs (mostly taken by Jacques Cadaugade from OMP) were collected during the various integration phases of ESPaDOnS. A small selection of them is presented below. Click on the small images to enlarge them.

The Cassegrain unit

The Cassegrain unit as a whole is shown on the right. Detail views of specific subunits or individual components are presented below:

The spectrograph

The spectrograph is the main module of ESPaDOnS, both in cost and size.

The top image on the right shows the image slicer module with the slit shutter (behind the small black disc in the middle) corresponding to where the photons are injected within the spectrograph; after a first pass on the main collimator (not visible on this image), the beam is dispersed vertically by the grating (on the right side of the image) before passing a second time on the main collimator; a first spectrum (running vertically) with all orders overlapping (no cross dispersion) is formed close to the flat mirror (visible at the immediate left of the slit shutter) before being reflected off to the other side of the spectrograph (transfer collimator, prism train, camera and dewar, all hiding behind the large black baffles visible on the left side of the image).

The bottom image shows a global view of the spectrograph taken from the other side and with the enclosure removed; while the image slicer module and the flat mirror are not visible here (being hidden by the grating mount), one can see (in additition to the grating mount) the main collimator and exposure meter (top right), the transfer collimator (partly hidden behind the rear baffle), the prism cage and the ccd dewar (partly hidden behind the front baffle). The dioptric camera between the prism train and the the ccd dewar is entirely hidden by the front baffle.

Selected images of individual components are presented below:

The spectrograph enclosure

For a good thermal and spectral stability, the whole spectrograph with its optical table is packed into an insulated enclosure. The enclosure is made out of an 80mm insulant sandwitched between two layers of epoxy; it consists of three main parts, the bottom section on which the optical table is resting, as well as two top sections (a large one on the mirrors side and a small one on the ccd side) capping the instrument; three trap doors (two on the large top section, and one on the small top section) enable access within the instrument for tuning purposes (during the setup stage). The trap door we see here is that giving access to the transfer collimator, prism cage, dioptric camera and ccd dewar (panel 2).

Colourful pictograms were added on all sides for those who cannot remember the instrument name. The big marlin with blue dorsal spikes occupying most of trap door 2 (painted by Nicolas Donati, age 9) is shown on the right; walking around the instrument can also bring you face to face with:

© Jean-François Donati, last update July 21 2004