* Take an arc to check that the grating angle is correct and to get an idea of the required exposure time (aim for at about 1000 counts in the weaker lines): in the ''Exposure/CCD info'' pane on the ''Main View'' tab, select "Exposure type" = ARC from the drop-down menu, and enter e.g. 10 seconds in the "Exposure time" box.
* If satisfied with the arc obtained, locate the ''Hartmann focus sequence'' panel in the ''Instrument Setup'' pane on the ''Main View'' tab of the SpUpNIC Control GUI (if not, adapt the exposure time and grating angle as required before proceeding).
* Select the ''Auto'' tab and enter the parameters for the Hartmann sequence: 3.75 for the ''initial focus position'', 0.05 for the ''focus increment'' and 9 for the number of ''steps'' - with the system still set up as it was for the test arc (lamp on, arc mirror in beam), click ''Run''. ''For some unknown reason, this routine might not work the first couple of times - in which case you should close and restart the SpUpNIC control GUI and try starting the Hartmann sequence again''.
* The slit width will automatically be set to 1.05" and the exposure type will switch to HARTMANN, then the GUI will grey out and not be available during the focus sequence (although you will see the ''Current Camera Focus'' field changing and the Hartmann shutters indicate ''Moving''.
* On completion of the sequence: in the SpUpNIC Quick-Look GUI, in the log box to the left of the spectrum display window, you will see a list of focus positions and their corresponding pixel shifts. Best focus corresponds to a shift of zero.