NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sundog
From: Bill B
Date: 2013 Feb 16, 14:10 -0500
From: Bill B
Date: 2013 Feb 16, 14:10 -0500
On 2/16/2013 12:54 PM, Greg Rudzinski wrote: > After closer inspection of the image ......large snip.... > Is there a UT time for the image ? Excuse my OCD. To solve a problem we first need to understand the problem. Frank stated: Lat 41d (Franks approx. location 41.5d N, 71.4d W) Hilly country ("Hilly" is relative. A hill in KS... ;-) YOU are facing the sundog YOUR sundog approx 5d high (using what as a horizon?) Sun blocked by hill to left Date February 10, (2013 assumed but not stated) Of importance Frank did not specify this is the sundog he saw, but rather the sundog YOU are facing. I think Frank's sundog was closer to 41.5d N. To me this means MY sundog could be at any longitude I specify near sunset. Where I place myself determines time and therefore declination. For simplicity of calculations MY sundog was at 41d N and 75d W. (a bit north of Philadelphia, PA.) 41d N and not too far from Frank, and hilly. (A look at a topo map of Frank's immediate area does not suggest it is a natural for development of a downhill ski resort.) Once you set YOUR longitude and determine approx time (and declination) when observed CENTER of sun would be 5d above the horizon and adjust for dip, refraction and temp/pressure just plug 41d, adjusted HO/HC and declination into the sine formula for azimuth. Add 22d and voila. That's my take on the king's new cloths ;-) Bill B On 2/16/2013 12:54 PM, Greg Rudzinski wrote: > After closer inspection of the image ......large snip.... > Is there a UT time for the image ?