[g__day (Matthew)]

An Idea occurred to me last night whilst I was tuning my SCTs collimination. Simply de-focus the star (I used Antares) take a shoy and measure on the screen how far the central black circle was off and adjust it until it is perfect.

So I am taking shots (see below) until with the image about 200 mm across and measuring the centre to within 0.5mm - anyone else tried this or have comments? It seemed to go quite well (to inexperienced me)!

Matt