Changes

Before each night's observations, you should focus the spectrograph. This is done using a scripted Hartmann sequence, which 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 can may be performed manually or , but is typically run automatically. For an auto focus run, as follows:# Above Take an arc to check that the grating setup, select slit width 7: 1.05" (or smaller) from the dropdown meny angle is correct and click "Go".# In to get an idea of the "Exposure/CCD info" "Advanced" subtab, select CCD modes "Faint" and "Slow" from required exposure time (aim for at least 1000 counts in the dropdown menus, and CCD Binning "1x2".# In weaker lines): in the "''Exposure/CCD info" "'' pane on the ''Main" subtabView'' tab, select "Exposure type" = ARC from the dropdown drop-down menu, and enter e.g. 20 seconds in the "Exposure time" box.# Move If satisfied with the arc mirror into obtained, locate the beam and switch on ''Hartmann focus sequence'' panel in the appropriate arc lamp for your grating setup.# In the "''Instrument Setup" section '' pane on the ''Main View'' tab of the SpUpNIC Control GUI(if not, select adapt the "Auto" tabexposure time and grating angle as required before proceeding).# Enter an "Select the ''Auto'' tab and enter the parameters for the Hartmann sequence: 3.75 for the ''initial focus position" (e.g. 3.80)'', a "focus increment" (0.05 is recommended) for the ''focus increment'' and a 9 for the number of "''steps" '' - with the system still set up as it was for the test arc (try 7 iterationslamp on, arc mirror in beam) and , click "''Run"''. # 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 Hartmann focus sequence, but (although you will see the current "''Current Camera focus" 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.# Enter the best focus into the "requested" ''Requested Camera focus Focus'' box on the SpUpNIC ControlGUI's "''Instrument Setup" window '' pane and click "''Go"''.# Switch off The Hartmann sequence ends with the arc lamp and move the arc mirror shutter out of the beam by clicking , but for some reason sends the slit width to zero! So select the desired slit width in the ''Instrument Setup'' pane and click ''Go''. Check that it goes to the required position, click ''Go'' again if it does not do it the first time.# Select "Exposure type" = ARC and take an arc to confirm that the focus looks good.# Click on the arc mirror in the schematic.# The Hartmann test ends with to switch off the shutter arc lamp and move the arc mirror out of the beam.