NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Definition of Arctic Circle
From: Nigel Gardner
Date: 2000 Oct 09, 6:06 AM
From: Nigel Gardner
Date: 2000 Oct 09, 6:06 AM
The Arctic Circle for navigators is the compliment of the obliquity of the ecliptic but will change of course with nutation, with a period of about 19 years. AC is also called the North Polar Circle but whether this is a geographers' term and if they have settled on a fixed value for its latitude or not I don't know. At one time the the name 'Arctic Circle' was used to describe the circumpolar path of the Great Bear. Back to the previous query as to whether the midnight sun was observable south of the Artic Circle, if the standard allowance for refraction and SD is applied then we can move 50' although funny things do happen to refraction at low temperatures, apply a bit for height of eye and we can move even further South. On the couple of occasions I have taken a midnight merpass shot the sun was looking like a badly poached egg and the limbs were difficult to make out. NG
