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SPUPNIC

30 bytes added, 18:44, 28 January 2016
/* Focusing the spectrograph */
* 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 remove the arc mirror and switch the lamp off. One can also control the lamps using the ''Lamp/Mirror Settings'' pane of the SpUpNIC Control GUI. Click the appropriate ''Change'' state button to switch the desired lamp on/off, and to move the arc mirror into the beam to take an arc exposure.
===Focusing the spectrograph- running a Hartmann sequence===
Before each night's observations, you should focus the spectrograph. This is done using a scripted Hartmann sequence run from the SpUpNIC Control GUI. The process moves a shutter halfway into the beam, takes an arc exposure; then blocks the other half of the beam and takes a second arc exposure. The arc lines are then cross-correlated to measure the shift between the two. The procedure is repeated at a range of camera focus positions until the line shifts are minimised, indicating best focus. This procedure may be performed manually, but is typically run automatically, as follows:
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