Just Turn Left At The Big Criss-cross

I HAVE yet to learn the fundamentals of celestial navigation. I have learnt other complex things; how to double-knot my shoelaces, for example, and how to kick a tyre knowledgeably. But I have never plotted a simple course without coming to grief. Smug bystanders (there are many smug bystanders in my life) loftily explain that night navigation is a piece of urine - simply fix your gaze on the Southern Cross and all falls into place. They lie.