Thank you Frank, I was not aware of the narrow use of the term for the sun's azimuth at sunrise and sunset. Bowditch (American Practical Navigator: An Epitome of Navigation) defines the term amplitude a little more broadly as "the angular distance north or south of the prime meridian ; the arc of the horizon or the angle at the zenith between the prime vertical and the vertical circle. I bow to your correct usage of the specific defined term and appreciate its usage. I tend to use just the general term azimuth.
Regards, Roger Bailey -------------------------------------------------- From: "Frank Evans" <[email protected]> Sent: Tuesday, April 28, 2009 7:28 AM To: "Sundial" <[email protected]> Subject: re sunrise > > Greetings, fellow dialists, > Thanks for confirming what I thought about the earliest time of sunrise > to light a declining dial. In defence of my use of "amplitude", meaning > the sun's azimuth at sunrise and sunset may I quote the (British) > Admiralty Navigation Manual, Vol. 3, 1938: "Amplitude. At theoretical > rising and setting the difference between 90 deg. and the azimuth is > called the bearing amplitude." I seem to recall that ships' chartrooms > used to carry tables of amplitude for compass checking purposes. > Frank 55N 1W > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.287 / Virus Database: 270.12.6/2084 - Release Date: 04/28/09 > 06:15:00 > --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
