Eric Hooper's been back from Wisconsin, working with the gang to get another RSS mode - Multi Object Spectroscopy (MOS) - commissioned during the past couple of weeks.
Here's what you see when you insert one of the laser-cut carbon fibre MOS slitmasks into the beam - all the individual slitlets & the pinholes for the reference stars appear to "light up".
The next image shows a MOS arc spectrum - each horizontal row is from a particular slitlet.
& here's a shot of the slitmask magazine - the masks on the left are the ordinary longslits & those on the right are the custom-made MOS masks.
This is one of the fancier masks that Eric tried out. It has some very small (short) slits to allow more sky measurements to be made closer to the target galaxy.
Intrepid Dr Hooper taking MOS flat fields at 4am!
Now in a slightly more flamboyant, telemarketer mode - offering us one of the RSS longslits... :)
Lastly - here's a regular longslit spectrum. In fact there happened to be 3 bright stars on the slit in this exposure, one of which is the X-ray transient MAXI J1836-194 that's in outburst at the moment...