A couple of years ago, I had a minor epiphany about the Moon. I wrote a post about it at the time, called ‘How to tell at a glance if the Moon is waxing or waning‘. Since then, when I’ve seen the Moon in its not-full phase, I’ve used my ‘wax on/ wax off’ rule (as described in that post) to determine whether it’s waxing or waning.
And in all that time, I can only remember ever thinking, “Ah, wax on!”. I can’t recall ever thinking, “Ah, wax off!”.
… until this morning, that is:
The Sun was coming up — and I suddenly realised why it was that I hadn’t seen a ‘wax off’ before. A waxing moon is on that part of its monthly cycle when it’s heading away from the Sun… and so it’s easy to spot, at night. When the Moon is waning, it’s on the Sun-ward side of the Earth, which means that, when it’s above the horizon, it’s more likely to be competing with the Sun, and so it’s not so easy to see.
… at least, I think that’s right. Assuming that it is, it’s entirely possible that you may be thinking, “Well, duh!” If so, please cut me a bit of slack; it’s taken me over half a century to figure it out on my own :)