* Two arc lamps are permanently mounted in the spectrograph - you no longer need to swap out a lamp - but the arc lamp filters are still changed manually. On the spectrograph, the CuAr lamp is in the vertical housing, with two slots for filters below. The CuNe lamp is below it, housed horizontally, similarly with slots for two filters in the light path. Filter requirements are listed in the table above and the filters are stored in a small, labelled wooden box on the bench in the grating room (North-West corner of the dome).
* The arc lamps are controlled from the "Lamp/Mirror Settings" section of the SpUpNIC Control GUI: Arc 1 is CuNe, Arc 2 is CuAr. Click the appropriate "Change" state button to switch the desired lamp on/off, and to move the arc mirror into the beam to take and an arc exposure, and out again when finished. Alternatively, click on the appropriate lamp icon in the instrument schematic - this will switch on the lamp and insert the arc mirror into the beam. Having taken the arc, simply click on the arc mirror icon in the schematic to switch off the lamp and remove the arc mirror. * The software now decides, based on which grating is in use and the angle at which it's set (whether it's being used in first or second order), which lamp to switch on once ARC is selected from the exposure type drop-down list.
===Focusing the spectrograph===