| Variable Star |
A star which has variable luminosity. |
| Vela |
The constellation "The Sail" |
| Velocity |
A quantity which describes both the speed and direction of an object. |
| Venus |
Venus is the second closest planet to the Sun. Venus' diameter is 12,100 km and takes 225 days to orbit the Sun. Venus is named after the Roman goddess of love. In Eastern Asian cultures Venus is also known as the 'Metal Star.' |
| Venusian |
Having to do with the planet Venus. |
| Vernal |
Having to do with the season of Spring. The Vernal Equinox is the beginning of Spring. |
| Vernier Scale |
A short scale made to slide along the divisions of a graduated instrument for indicating parts of divisions, to obtain very fine adjustments. |
| Very Large Baseline Interferometry VLBI |
A technique to connect widely separated telescopes to make observations with very high resolution. |
| Vignetting |
An optical problem where an image is missing its edges. This is cause by the eye or camera not being properly aligned with the focal plane. Its effects sometimes appear as tunnel vision. Common causes would be: 1) With binoculars, if the distance between the eyepieces are not properly adjusted for the observers eyes. 2) With binoculars and telescopes, if the eye or camera is too close to the lens. (i.e. Too close for the Eye Relief). 3) With Afocal photography, this is a common problem if the lens of the camera is not aligned to the eyepiece, or if the eyepiece is unsuitable for the camera lens and telescope. |
| Virgo |
Virgo (The Maiden) is a zodiacal constellation, that is, it lies across the ecliptic, an imaginary line across the sky that the Sun, Moon and all the planets except Pluto seem to move along. Inside the constellation of Virgo is a collection of galaxies in the Messier Catalog include the elliptical galaxies: M49, M59, M60, M84, M86, M87, M89, and the spiral galaxies: M58, M61 and M90. Also in Virgo is the Sombrero Galaxy known as M104. Virgo over time has been associated with many goddesses, but usually is associate with Astraea, the goddess of justice, holding the constellation Libra. |
| Visual Back |
An adapter which threads on the rear cell of a catadioptric telescope to hold the optical line, usually interfacing with a diagonal. |
| Volans |
The constellation "The Flying Fish" |
| Vulpecula |
The constellation "The Fox" |
