YASSP - Yet Another Simple/Slit Spectrograph
This first slit spectrograph was designed by K.-H.Uhlmann, M.Jung and M.Kretlow in 1996 for the observation of comets. We decided to use an Amici prism (part. angle dispersion 4°35') to get as much light as possible. Because of a limited money budget the slit was made using razor blades and the imaging lens was an ordinary photo lens. Changing the focal length of this photo lens we could variate the scale of the resulting spectra. Disadvantage is the non-linear diespersion, which makes the calibration more difficult.
This spectrograph was re-designed a couple of months later, resulting in YASSP2.
The mechanical assembly of the first spectrograph was not very professional. It was hard to adjust all optical components and so we decided to re-design the spectrograph and to built it again to be better prepared for promising comet Hale-Bopp. Meanwhile M.Jung had all the machines to make the mechanical componets by his own. We changed the concept and assembled all components in a line (not in a 90° angle), because the optical alignment should be easier. Unfortunately building this spectrograph tooked us a more time than expected and we were really late starting with the observations of comet Hale-Bopp.
We were not very happy with the non-linear dispersion due to the prism and also the resolution of the spectrograph was not so good. So we thought about a new spectrograph using a grating even in 1997 but it tooked until 2002 when Matthias built YASSP3.
The image below shows the spectrograph. The box at upper right is the Audine camera, to the left you can see the control scope.
A simple construction schematic is given below:
And the following figure gives the response function of the used grating (green line):