Posted by Robin Vann at 15:32 on 2010 Sep 07
Thanks Andrea.What you say makes perfect sense. If I move my eye slightly off-centre to the axis of the Cheshire, everything lines up, but I then can’t see the inside surface of the Cheshire on both sides. I have also never seen the Airy disc though I have attempted to many times since starting astronomy in May this year. I have previously put this down to the inadequacies of the coarse rack and pinion focuser but, overall, I now suspect the telescope was delivered with the secondary offset incorrectly in the way you describe.I shall now try to move the secondary so that my Cheshire cross-hairs are correctly centred over the centre marker of the Primary before realigning the primary to centre the reflection of the secondary over said centre marker.Robin Vann