Years ago it was mentioned to me the New Yorker magazine had a Young Moon “contest”; who could find the youngest moon; the thinnest crescent after a new moon. I knew enough to know that I would have to know exactly when the new moon occurred and more importantly where. The Thin Crescent wouldn’t be too hard as it would follow closely the sun. Still, not knowing where the new moon happened meant that I could see anything from nothing to a one day old moon. I knew the moon traversed about 13 degrees of arc a day in so doing about 7% Of its disc was illuminated so my chance of seeing a very thin crescent depended on the new moon happening to the east of me by some 6 to 12 hours, as the “record” was something in the realm of 9hours.
So the question arose in me “Where on the globe would an observer see any of the quarterly phases exactly over their meridian?” This question led to almanacs that used hours, minutes, seconds and hundredths of seconds of measurements, all starting from the celestial spheres Greenwich or zero longitude, the Vernal Equinox, that semi-fixed(a 26,000 year cycle) starting place for celestial longitude. My question is, how can I find and use that “exact” beginning zero “longitude?
I am being hobbled here by being forced to use the very nomenclature I don’t understand. I mean I understand it, it’s simple enough, I just don’t know where to start. How do I find right ascension 18h23m52.34s on the celestial sphere? Is there a bright star at the vernal equinox that is used to fix that spot in the sky?
I begin to think I’m communicating with a machine that can’t extrapolate...no matter, as long as I get an education. Ok then here’s a question: how can I find right ascention(ra)18h 23m 52s standing out in the desert some night? I don’t need declination as the object is large and I’ll know it when I see it.