The consortium attempted to design and construct a PN Spectrograph to operate at several good sites using 4-m and 8-m class telescopes. Although formal arrangements have yet to be made, our idea is arrive at a design which can be operated at the 4.2-m William Herschel Telescope (WHT) and at the 3.5-m Italian Galileo telescope (TNG). In addition we hope to work with the European Southern Observatory (ESO) towards the construction of a version for the 8-m VLT.
The general design philosphy is as follows:
After conducting two design studies (PNS-1 and PNS-2) we are proceeding with a modified PNS-1 design. There will be two collimators (f/15 for VLT and f/11 for WHT and TNG). All three version will use the same camera. The two images required for PN velocities can be generated by rotating the spectrograph between exposures. Alternatively the pupil can be split as in the PNS-1 design study.
Compared with the original PNS-1 study for the AAT:
In the end, the compromises required to "feed" a 4-m and 8-m telescope became too great and the consortium abandoned this idea. Instead, a dedicated (but not optimised) VLT design was arrived at (designated 3.17V) and archived for future study, while work proceeded on the WHT/TNG version.