[ATM] Need help: Where's spica?
Douglas S Angle
Douglas.S.Angle at can.dupont.com
Tue May 11 23:23:04 JST 2010
I did some surveying, and used Polaris and Spica to orient my
measurements. I thought it would be easy from there to convert to
azimuth, and therefore find true north to a fairly high precision. I then
fired up Cartes du Ciel to do the conversion. It's not clear how it
handles daylight savings time, so I cross checked against Desktop
Universe. That's where my troubles began.
For example, DU with daylight savings turned on, gives azimuth of 164d 41m
for Spica. CdC doesn't have a daylight savings setting, but using an hour
earlier gives the same siderial time (12:23:12), but then yields azimuth
of 161d 31m for Spica. Further, the rise, set and transit times are
different by about 5 minutes between the two programs.
I specifically used star positions to give me accurate directions, but now
I have a discrepancy of 3 degrees in the calculated positions!
In summary, from these measurements, how do I get the 3 Azimuth values?
Location 44d 25m 42s N 76d 23m 28s W
Polaris 21:42 Eastern Daylight time
This communication is for use by the intended recipient and contains
information that may be Privileged, confidential or copyrighted under
applicable law. If you are not the intended recipient, you are hereby
formally notified that any use, copying or distribution of this e-mail,
in whole or in part, is strictly prohibited. Please notify the sender by
return e-mail and delete this e-mail from your system. Unless explicitly
and conspicuously designated as "E-Contract Intended", this e-mail does
not constitute a contract offer, a contract amendment, or an acceptance
of a contract offer. This e-mail does not constitute a consent to the
use of sender's contact information for direct marketing purposes or for
transfers of data to third parties.
Francais Deutsch Italiano Espanol Portugues Japanese Chinese Korean
More information about the ATM