Originally Posted by
n5296s
Supposing this to be true (I have no idea for the moon bit, though I certainly agree for the sun bit), why is it of any practical use to know it when flying? You're not going to choose a destination based on the way the moon is shining. So once you get up there, whatever it is, it is. If you notice that you can make out ground features better on one side of the aircraft than the other, and this is useful, good for you. If you're flying at night you're hopefully not relying on pilotage for navigation anyway. This seems like it could have been a useful thing to know ahead of time in about 1920, before there was anything BUT pilotage.
You've been told it's true so there's no need to "suppose" anything, or don't you believe us?
Practical use? Use a bit of imagination. Planning a flight in hazy conditions you'll know from which direction it's best to approach the field in order to find it. This is particularly important for people flying to farm strips or helo landing sites. It also tells you if your nav is going to be affected by poor forward visibility hindering the "pilotage" (I assume you mean conventional navigation) that you seem to be so dismissive of - despite an awful lot of people still doing it and not just following a magenta line. It'll also suggest that landmarks upsun or downmoon of your track may not be as easy to spot as those in the opposite direction or that a runway oriented in the "wrong" direction might turn out to have unacceptably poor vis for a safe landing.
Why would one "hopefully not" be relying on conventional nav at night? Is there something wrong or risky about it? Or are you just a child of the magenta line and can't actually navigate?
fyi conventional navigation (pilotage?) didn't end "in about 1920", there was nothing else until satnavs became available about 1990. Even if you were clumsily flying VFR via VORs and NDBs you still need to see the destination...
Thus I submit this is a pretty useful bit of knowlege.