Thanks one and all for your feedback....
On the subject of elongated stars
.... I have been doing some fine tuning of my RC system recently using CCDinspector software.
Some results can be seen here
http://www.atscope.com.au/BRO/tutori...inspector.html
It's certainly a useful tool, but does give different colimation resuts by simply imaging a different star field, or with the same field but with different seeing or with a slight focus tweak
That said, subtle tweaking of a system can make significant differences the overall performance....just need some clear weather to see the
results!