A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tony Oz
Date: 2021 Sep 6, 04:42 -0700
Quite often there are conditions (at 60°N 30°E) that are not handled by "usual" refraction correction tables.
This happens when the cold air is above much warmer water, and some sort of miraging appears. In less severe form - the line of sight bends upward hiding low objects on the horizon that are usually visible.
I have two questions here:
- how does this atmospheric condition affect the refraction at higher angles? Say, the angles more than 15°?
- is this line of sight bending equivalent to the additional Dip, HoE change or me being further off from an observed body?
Is it correct to say that such a bending (cold air above warm water) makes apparent Earth "more round" (i.e. of less equatorial radius)? And the opposite condition (warm air above cold water) makes Earth "flatter"?
I need a way to understand these aspects to be able to quickly judge what the error in my intercept will be - will I be "away" or will I be "toward" - to compensate for this offset.