Astronomical Refraction
This definition page has been automatically generated. You can help ExoDictionary by expanding, updating, or correcting it. |
| This autostub has not yet had its initial copyediting proof and may contain significant formatting and even factual errors. You can improve Exodictionary by cleaning up the page markup and verifying that the definition is correct and then removing this tag. |
| This autostub has not yet had its initial categorization proof and may be categorized incorrectly. You can improve Exodictionary by removing inappropriate categories and then removing this tag. |
Astronomical Refraction
1. The angular difference between the apparent
zenith distance
of a celestial body and its true zenith distance, produced by
refraction effects as the light from the body penetrates
the atmosphere. Also called atmospheric refraction, astronomical
refraction error. See
Bemporad formula.
For bodies near zenith the astronomical refraction is only
about 0.1 minute, but for bodies near the horizon it becomes about
30 minutes or more and contributes measurably to the length of
the apparent day.
2. Any
refraction phenomenon observed in the light
originating from a source outside of the earth's atmosphere; as
contrasted with terrestrial refraction. This is applied only to
refraction caused by inhomogeneities of the atmosphere itself,
and not to that caused by ice crystals suspended in the atmosphere.
References
This article is based on NASA's Dictionary of Technical Terms for Aerospace Use
