Hi Shea, > Recently, I've found something wrong in Heavens Above's prediction > on Iridium Flares. ... Most of them are right, but the Alt. is > wrong. The observation is that Alt. is nearly 90° [versus 60° > observed]. The error is roughly 30°, so great! You may be surprised at just how high in the sky the zenith really is -- it is not a comfortable direction to be looking while standing, and consequently most beginning observers overestimate all elevation angles -- with increasing errors as the angle increases. Here is a typical altitude angle conversion table I use for "translating" beginners' reported altitude angles: Reported Actual Angle Angle -------- ------ 10 7 15 10 30 20 45 30 60 45 80 60 90 70 Try testing yourself with some bright stars that are well above the horizon -- guess their altitude angles and then use one of the many planetarium programs out there to see how close you were. You may be surprised by the results. Best wishes, Rob ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Wed Jul 31 2002 - 21:20:56 EDT