I find useful this rule of thumb : What is the Sidereal Time at a given time ?
S. T. (hours) = time (hours)- 12 + 2 x (number of months from March 21) This is nice to know immediately what constellation passes the meridian at a given time and roughly reproduce the sky using a map ... Alberto Nicelli Italy ( 45°28' N ; 7°52' E) -----Messaggio originale----- Da: Steve Lelievre [mailto:[EMAIL PROTECTED] Inviato: lunedì 24 gennaio 2000 2.35 A: Sundial mailing list Oggetto: Rules of thumb I'm relatively new to dialing, and indeed this is my first post to the mailing list (but I've lurked here for a few months). I'm also a great enthusiast for using "rules of thumb" in everyday life, but so far I've not found many cases where I can put the two together. I'm hoping that this posting will lead to a discussion about rules of thumb which bear on sundials / sun naviagation / sky navigation. Here are a few examples of the kind of thing I mean: - Point the hour hand of your watch in the direction of the sun. Divide the angle between the hour hand and the 12 o'clock position. This shows you where North/South are. - Put a stick in the ground. Use a pebble to mark where the tip of the shadow is. Wait a few minutes, now make a line from the pebble to the new position of the shadow tip. This is an East-West line. Of course, these two are not accurate - rules of thumb often aren't - but I'm hoping a few gems will turn up. Anybody got any, good or bad? Especially ones for telling the time. Steve
