The telescope light path is that of a typical cassegrain telescope.
However, the light path of the telescope is blocked by two items,
the rain screen and mirror cover (Figure 1).
The white rain screen is mounted about half way down the telescope tube. It operates like a roller blind and is not remotely operable. The cord is on the north side of the telescope (Figure 2). To retract the rain screen, just unwind the cord from the hook and allow the screen to fully retract (the end of the cord will hang free). To deploy, pull the cord until the screen if fully covering the aperture of the telescope, then carefully wind the cord around its hook. Do not tie the cord into a knot, a few figure eights around the hook should hold it firmly in place.
Always deploy the rain screen when the telescope is stowed or the weather is threatening. For remote Nickel operations the rain screen will be retracted and deployed by the Observatory staff.
The mirror cover is opened and closed pneumatically. The mirror cover is operated remotely via the naux_fe software, though it can also be opened and closed from switches in the dome (Figure 3).
Please make sure the mirror cover is closed before moving the rain screen or dome shutter. This will ensure that the mirror is protected from any falling dust or debris.
Figure 1: Rain Screen and Mirror Cover
Figure 2: Rain Screen Cord
Figure 3: Mirror Cover Switches