* Using the hand paddle, move the telescope to place the star on the slit, approximately one third of the image width away from the right-hand edge.
* Turn off slit illumination.
* Click on the icon [[File:Potcamicon.jpg|100px|thumb||Rear of slit camera icon50px]] for the rear of slit camera (on the left-hand panel) * Open a terminal on Monitor 1, and run the following commands: * ssh -Y tcs@172.17.1.224 * password ******* (you should have been supplied with the password) * sudo ./1X1_thread_forms -depth 24 * password *******
* An image window for the rear-of-slit camera will pop up. This looks up at the slit from behind, to enable you to check that your star is centred on the slit. Move the telescope such that the star falls on the centre of the slit image in both x and y.
* Move the rear of slit mirror out of the beam and take a test spectrum (e.g. 20 seconds) of the bright star (in the ''Exposure/CCD info'' pane, select ''Exposure type'' = SCIENCE from the drop-down menu, enter ''20'' in ''Exposure time'' and click ''Expose'').