Antisolar point
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Double-alaskan-rainbow.jpg/290px-Double-alaskan-rainbow.jpg)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1d/Subparhelic_circle_flickr_fdecomite.jpg/220px-Subparhelic_circle_flickr_fdecomite.jpg)
The antisolar point is the abstract point on the celestial sphere directly opposite the Sun from an observer's perspective.[1] This means that the antisolar point lies above the horizon when the Sun is below it, and vice versa. On a sunny day, the antisolar point can be easily found; it is located within the shadow of the observer's head. Like the zenith and nadir, the antisolar point is not fixed in three-dimensional space, but is defined relative to the observer. Each observer has an antisolar point that moves as the observer changes position.
The antisolar point forms the
Also around the antisolar point, the
Anthelic point
The anthelic point is often used as a synonym for the antisolar point, but the two should be differentiated.[1] While the antisolar point is directly opposite the sun, always below the horizon when the sun is up, the anthelic point is opposite but at the same elevation as the sun, and is therefore located on the parhelic circle. There are several halo phenomena that are centered on or converge on the anthelic point, such as the anthelion, Wegener arcs, Tricker arcs and the parhelic circle itself.[6][7][8]
See also
References
- ^ ISBN 081099397X.
- ^ Cowley, Les. "Primary rainbows". atoptics.co.uk. Retrieved 13 September 2013.
- ^ Cowley, Les. "The Glory". atoptics.co.uk.
- ^ Cowley, Les. "Anticrepuscular rays". atoptics.co.uk. Retrieved 13 September 2013.
- ^ Cowley, Les. "Antisolar or anticrepuscular rays". atoptics.co.uk.
- ^ Alexander Wünsche; Jim Foster, Anthelion and anthelic arcs, 2006
- ISBN 0875908349, American Geophysical Union, 1994, p. 27
- ^ Les Cowley. South Pole Halos – Anthelic View – Atmospheric Optics Archived 2015-09-23 at the Wayback Machine, accessed 13 September 2013