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    Direction from the stars solved at last.
    From: David Pike
    Date: 2022 Jan 13, 09:55 -0800

    We’ve had a couple of clear nights recently and I was out last night checking time from Merak, Dubhe, and Polaris against my watch for the first time.  That worked well, so I turned my attention to direction from Orion’s Sword, which has never convinced me.  The North Celestial Pole isn’t much use to me because it’s way over my shoulder.  However, logic says south should be in the opposite direction, but no way did the far end of the arrow twisted 8 degrees anticlockwise pointed anywhere near south on my horizon.   

    Today, it struck me.  Unlike Polaris, tricks such as these only point you towards the celestial poles, not to where north or south is on your horizon.  The late-night navigator usually wants to know where north is on their horizon.  Dropping a vertical from Polaris gives this directly.  Achieving north or south on the horizon from Orion’s sword is very latitude dependent.  On the Equator, it’s tail end always points to south on the horizon.  The farther north you go, the more it only works when the sword is close to vertical, so it doesn’t work well all night. 

    In mid-latitude USA, where much online content comes from, it’s acceptable for most of the night, but in the UK 20 degrees or so further north, when people try to follow the same online content, it doesn’t work very well at all and leads to all sorts of confusion. 

    So, what does work in the UK?  Well Mintaka rising on E and setting on W works well, but you’ll only see one of these per evening so take care not to miss it.  A certain amount of forward or back projection to clear the trees at an angle equal to your co-latitude to the horizon is permissible.  DaveP

       
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