Astro*Dictionary by Michael Erlewine
2 articles for "Refraction"
Refraction [Astro*Index]The bending of light rays as they pass from one transparent medium to another transparent medium of a different density, e.g., from air to water, or interstellar space to air. This is important when viewing planet's rising or setting and can amount to a positional correction of about 34.5' at an altitude of 0°; i.e., on the Horizon.
See also:Refraction [Munkasey M.]
♦ Rise/set/transit
The apparent "bending" of the light rays from a body asits ligh passes through the Earth's atmosphere. The bending is greatest near the Horizon, and is of such a nature that the body can be "seen" after it has astronomically "set". The nominal refraction at an altitude of zero degrees is about 34.5 minutes of arc.
See also:
♦ Rise/set/transit
Astro*Index Copyright © 1997 Michael Erlewine
Free Stuff: