Fr. Wayne
17-January-2006, 11:47 AM
Back in 1997, I found a simple method for reading the R.A. (Right Ascension) of the zenith using the "pointers" of Ursa Major ("the Big Dipper"):
23h - 2p= R.A. of zenith (I call it Fr. Wayne's Star Clock)
Pretend you had a watch with only an hour hand, you could learn to read the hour of the pointers (always use Polaris as the end, and Mizar as the center of hour hand). h= hr. p= line of sight hour from Merak (thanks moderator, not Mizar) to Polaris or [1 - 11, 12=0] FIND the POINTER. DRAW LINE to POLARIS. READ the HOUR HAND. PLUG into FORMULA. Voila! even in the darkest night, at least you'll know the Zenith's Right Ascension Hour. Get good at it and you can read 1/2 hours too. (ex. 23h - 2 (11.5)= 0 hrs R.A., this is the hardest as people south of Canada can't always see the Big Dipper when it DIPS to the max)
23h - 2p= R.A. of zenith (I call it Fr. Wayne's Star Clock)
Pretend you had a watch with only an hour hand, you could learn to read the hour of the pointers (always use Polaris as the end, and Mizar as the center of hour hand). h= hr. p= line of sight hour from Merak (thanks moderator, not Mizar) to Polaris or [1 - 11, 12=0] FIND the POINTER. DRAW LINE to POLARIS. READ the HOUR HAND. PLUG into FORMULA. Voila! even in the darkest night, at least you'll know the Zenith's Right Ascension Hour. Get good at it and you can read 1/2 hours too. (ex. 23h - 2 (11.5)= 0 hrs R.A., this is the hardest as people south of Canada can't always see the Big Dipper when it DIPS to the max)