[thegableguy (Chris)]

Sorry to lump two different questions in together - seemed fairer than starting two new threads.

What is considered a good benchmark for successful guiding / alignment? I'm halfway through tonight's capture and all adjustments seem to be under 1", with maybe one little spike per minute on average going just beyond 1". Is that good, average or bad? It's the best I've managed so far but maybe I can do better...? I haven't touched any of the settings in PHD2, it's all just default settings (mainly because I don't know what any of the settings actually do).

Secondly, can someone help tell me what the results look like when a reflector needs collimating, and how they're different to having an improperly spaced coma corrector? Does one produce stretched stars all over, and the other only at the edges? Or does one create yellow haloes around stars and the other not? Or does improper spacing basically mean you can't focus properly? Any help welcome.