Checking the Light Beam

If the telescope is operating normally but you can't see any images on the Finder TV, The Cassegrain TV or the CCD (at Prime), check the following possible causes:

• Is it cloudy? Go outside and look for yourself.
• Is the dome closed or is the lower shutter vignetting the beam?
• Is the dome open but pointing in the wrong direction. This can happen if the dome is switched to MANUAL or if there is a malfunction of the dome rotation or the dome rotation encoder.
• Are the primary or secondary mirrors still closed?
• Is the finder cover closed?
• On the Cassegrain A&G box check that the autoguider probe isn't close to the centre and thus vignetting the beam.
• Is the telescope somewhere near its nominal focus? It sometimes happens that on startup the focus runs away to 62 mm. At this setting the image is so far out of focus that it is very difficult to see stars on the TV.
• Are the TV cameras running normally with the gain fully up and no warning lights showing?