* Using the hand paddle, move the telescope to place the star on the slit, approximately one quarter of the image width away from the right-hand edge.
* Turn off slit illumination.
* Click on the icon [[File:Potcamicon.jpg|50px40px]] for the rear of slit camera (on the left-hand side of Monitor 1).
* An image window for the rear-of-slit camera will pop up. This looks up at the slit from below, 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'').