+36 is a bit hard for me I'm afraid.
I've had a question about how this all works so here is my simple answer.
The spectrograph essentially has a little glass mirror in it with a narrow gap in the mirror. This is the "slit". It is 23um wide. The telescope focuses an image onto the mirror and a small, narrow band of light passes throught the gap in the mirror. The image that I posted is an image from a guide camera. it looks at the front of the mirror so you see the star field with a "gap" in it. The quality of the image is pretty crappy because to achieve the focussed image of the mirror, the guide camera has to look through a small doublet lens. This is not high quality as it is only intended to assist in centering the target on the slit and guiding.
The light that passes through the slit is then focussed by a lens onto a dispertion grating which then splits it into the spectrum. This is then refocussed onto the imaging camera to produce the image of the spectra.
I then select a small vertical region of this and to create the graph of the spectra. Just after taking the images I then illuminate the slit with a neon light. This then produces a spectra of the neon that can be used to calibrate the spectra of the target.
The spectra are always displayed with the blue end to the left and the red to the right.
All as clear as mud.
Terry
