Changes

** The ''Advanced'' tab, used at the start of the run, and which may be used if things go wrong(e.g. to reset or initialise mechanisms).** The ''Engineering View'' tab, which displays various diagnostic settingsand allows one to check the CCD and cold finger temperatures.** The ''Config'' tab, which you should not need for the most part, although this is where the temporary software lock for the grating is now.

* The panel on the right is an interactive schematic representation of the instrument. Components with in/out or on/off states can be toggled by clicking on the relevant part of the image. The light path is shown in red so that one can easily verify the instrument configuration.

* '''N.B.''' We have now installed a physical brake on the grating to address the instability problem mentioned below. This means that you can not One cannot change the grating angle when the brake is applied, and we have disabled the ability to change the grating angle in softwareto prevent accidental damage. This can be re-enabled, but only when the brake is not applied. A technician is therefore required to disable the brake and change the grating angle. And hence for changing gratings as well, since the angle needs to be set to zero in order to remove/insert a grating.

* '''Warning:''' During your start-off you will have been told about the grating instability problem. We applied a mechanical fix when the instrument is off the telescope in early April. This improved the situation, but did not completely resolve the issue - so until such time as we have completely fixed eliminated the problem, we urge users to bracket all target observations with arcs (to be taken immediately before and after the object exposures) to minimise the impact of the declination-dependent movement of the grating.

* The angles listed in the right hand column of the table are just to below will get one into the range where lines are visible for a given grating. One , then needs to adjust the grating angle to obtain the desired wavelength range - consult the arc maps in the old spectrograph user manual (a hard copy is available in the warm room).

- N.B. A a technician will need to be called to help with this, as the grating brake mechanism precludes users from changing the grating angle.

* Once you have the correct grating in the spectrograph, enter the approximate starting angle (given in the grating table above) in the ''Grating angle'' box and click ''Go''. Compare the resulting arc spectrum with the arc maps in Chapter 10 of the old spectrograph manual. Automated grating angle determination is on the way, but has yet to be implemented in the Quick-Look GUI.

- Before open up the south cover of the instrument (it does not need to be fully removed, just opened enough to be able to access the brake) - before changing the grating angle, disable the physical brake on the grating, inside the instrumentby slightly slacking off the 4 black bolts - In in the software, go to the configuration ''Config'' tab, push click the "''Unlock" '' button, and enter the password. - Still still on the config ''Config'' tab, push click the "''Deactivate Grating Brake" '' button (this will change to say "''Apply Grating Brake"''). - After after the grating brake has been released in software, the initialize, initialise grating angle entry and the grating angle "''Go" '' buttons should all will be enabled. - Reset and/or initialize if necessary. initialise the grating on the ''Advanced'' tab - In in the main control ''Main View'' tab, enter the required grating angle and push click the "''Go" '' button. - Once the grating observer will need to take arcs and compare them to arc maps in the old spectrograph manual (adjusting the angle until they're happy with the set of arc lines landing on the CCD) - once the desired angle has finished movingbeen set, push the "click ''Apply Grating Brake" '' in the config ''Config'' tab. - Lock lock the config grating on the ''Config'' tab. - Enable enable the physical brake on the grating, (inside the instrument.) by tightening the 4 black bolts (do this very carefully to avoid disrupting the grating as that would slightly change the angle and the process may need to be repeated) - close up the south cover of the instrument

* 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 CuNe lamp (Lamp 1) is in the horizontal housing, with two slots for filters in the light path. The vertically housed CuAr lamp (Lamp 2) is above it, similarly with slots for two filters at the bottom. 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 on the NW side of the dome).

* The software now decides, based on which grating is in use and the angle at which it is set (whether the grating is being used in first or second order), which lamp to switch on once ARC is selected from the ''Exposure type'' drop-down list on the ''Exposure/CCD info'' pane.

====Focusing the spectrograph 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 it is typically run automatically, as follows:

* Select the ''Auto'' tab and enter the parameters for the Hartmann sequence: 3.75 6 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''. <big>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</big>.