Posts Tagged ‘astrophotography’

Coma

There are several astronomical meanings. It can be used to describe the hazy looking patch that surrounds the nucleus of a comet or the blurred effect surrounding the images of stars on a photographic plate, or in the observers field of view in a telescope (or binoculars) due to defects in the lenses.

Bolide

An extremely bright meteor, also called a fireball.

Bailey’s Beads

Brilliant points of light along the edge of the moon disc, just at the start or the end of totality of a total solar eclipse.When caught on camera they are spectacular and can give the diamond ring effect.

They are caused by the irregularities at the edge of the Moon’s disc when seen from Earth. These irregularities are in fact the hills and valleys of the Moon. It is the valleys that allow the light from the Sun to reach the observer when the Moon obscures the Sun.

Book:

How to observe eclipses

Aperture

Aperture is the diameter of the main lens or mirror of a telescope in inches or cm.

The larger the aperture, the greater the light grasp and resolving power. Optical instruments with a larger aperture can therfore see fainter objects and separate more closely spaced objects.

The effective aperture of a reflecting telescope is reduced by the secondary mirror. Size for size therefore, a refracting telescope is better.

The Analemma

In everyday language, an analemma is the base of a sundial but in astronomical terms it means the angular offset of an astronomical body from its mean position.

When astronomers refer to the analemma, they are normally referring to that of the Sun.

If you take a picture of the Sun at the same time each week, from exactly the same position, on a single frame of film, the figure of eight shape that results is called the analemma. It takes patience and dedication to take a photograph of the analemma.

Wikipedia article

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