AEST :- Australian Eastern Standard Time

ACST :- Australian Central Standard Time

Aberation of starlight :- The apparent displacement of the true position of a star due to the velocity of light (299,792 km/sec) and the Earth's movement around the Sun

Absolute Magnitude :- The apparent magnitude of a star if observed from 10 parsecs (32.6 light years)

Absolute Zero :- The lowest limit of temperature (-273.16 C or 0 Kelvin)

Absorption (of light thru space):-. The amount of light absorbed by interstella material

Absorption Spectrum :- Dark lines appearing against a bright background or continuous spectrum. This occurs because of atoms absorbing certain characteristic wavelengths from the continuous spectrum.

Acceleration :- Rate of change in velocity. Usually acceleration refers to increase in velocity; deceleration refers to a decrease in velocity or negative acceleration.

Achromatic lens :- Lens free from chromatic abberation due to the placing together of two glass lenses to compensate for dispersion.

Aerolite :- A stony meteorite

Aeropause :- The region of the atmosphere where the air density is so slight it can be almost disregarded> This is a transition zone with no distinct boundaries between the atmosphere and space . Approximately 700km-1500km for objects with low surface to mass ratios ...

Airglow :- The faint natural luminosity of the night sky due to interactions in the Earth's upper atmosphere

Air resistance :- Resistance to a moving body due to friction with the atoms in the atmosphere An object in space will continue to orbit indefinitely unless its orbit enters regions where air resistance will gradually slow the object causing its orbit to decay

Albedo :- A measure of the reflective characteristic an object in space (Planet/Asteroid) Expressed as a ratio of the amount of reflected light from an object to the amount recieved from a source eg. the Sun. A perfect reflector would have an albedo of 1.0 or 100%

Altazimuth mount :- A mounting which allows a telescope to move in both altitude and azimuth

Altitude :- The position of a celestial body above the horizon expressed in degrees alt. The horizon being 0 deg.alt and directly overhead the zenith 90 deg.alt.

Angstrom unit :- The unit for the wavelength of light and other electromagnetic vibrations.......... Equal to 1/100,000,000 cm.Visible light;red 7500A, to violet 3,900A

Angular diameter :- The apparent size of an object measured in degrees or radians

Angular momentem :- The product of the moment of inertia and the angular velocity

Angular separation :- The angular distance between two bodies measured in degrees

Antenna :- A system of conductors for radiating or recieving radio waves.

Antenna array :- A number of antennae joined together into a system to increase sensitivity or directional effects Radio telescope as used in radio astronomy

Apastron :- The point at which the orbiting stars in a binary star system are the greatest distance from each other. The opposite to periastron (the closest point)

Aphelion :- The position where a body is at the most distant point of its orbit around the Sun The opposite to perihelion (the closest point)

Apogee :- The position where a body is at the most distant point of its orbit around the Earth The opposite to perigee (the closest point)

Apparent Magnitude :- The apparent brightness of a star/celestial body as observed from Earth mag.12 faint telescope object; mag.6 faint naked eye object;mag.1 to mag.-1 brightest stars (Antares to Sirius)

Arc,degrees of :- 1/360 of a full circle

Arc;minute,second :- 1/60 of a degree. One minute of arc (1') is divided into 60 seconds of arc (60")

Asteroids :- Thousands of asteroids have been identified, most orbit between Mars and Jupiter The larger ones like Ceres (1003km across) and Vesta, visible to the naked eye are also called minor planets

Astrology :- A Proto-science derived from ancient civilization's attempts to make sense and find order in the cosmos. Over thousands of years, shifts in the positions of constellations due to precession have made the foundation Zodiac constellations inappropriate and inaccurate.

Astronomical :-

Astronomical Observatories :- Anglo-Australian Observatory

Astronomical Societies :-
Astronomical Association of Queensland :-
Astronomical Society of Victoria :-
Brisbane Astronomical Society :-
Bundaberg Astronomical Society Incorporated :)

Astronomical Unit :- The distance between the Earth and the Sun. (1 AU. = 149, 597, 900 kms): 150 million kilometers approx.
Astronomy (see Astronomical):-

Australian Astronauts:-

Andrew Thomas: Veteran Australian astronaut STS 77, Mir, STS102......

Phillip. K. Chapman: ....The first Australian to be trained as an Apollo astronaut, he was born in Melbourne....

Paul Scully-Power : ....The first Australian in space, trained as a Shuttle mission Specialist

> see more history of Australian Astronauts

Australian weather:- .................... ............................... Australian weather; Satellite maps, forecasts
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B.A.S.:-
Brisbane Astronomical Society :-
B.A.S.I. (Bundaberg Astronomical Society Inc.) :-
Established in 1963, The Bundaberg Astronomical Society operates from 'Alloway Observatory'using a 480mm Newtonian Reflecting telescope.
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Background radiation :-
Microwave radiation coming continuously from every direction in space. COBE (Cosmic Background Explorer satellite detects variations)
Baily's Beads:-
Points of light seen during total eclipse as the Sun's rays pass thru valleys on the Moon's surface
Barycentre:-
The Earth-Moon system's centre of gravity, which lies within the body of the Earth due to it being 81 times the mass of the Moon
Binary-star system:-
A frequently occuring star system with two components orbiting around a common centre of gravity. Binaries with very small angular separation can be detected using spectroscopy
Bits:-
Binary digits for coded data storage and transmission
Black holes:-
There are three types known, between a 3 solar mass and a suspected 2.5 million solar mass black hole in the centre of our Milky Way galaxy. Simple Black holes are detected by their mass (gravity effects on nearby stars)other types emit x-rays or pulsing radiation because of spin and charge
Bode's Law:-
A formula for predicting the orbital distance of planets in our Solar System based on a series 0, 3, 6, 12, 24,doubling the number each time, then add 4 to each No. in the series and divide by 10 to get .4, .7, 1.0, 1.6, 2.8, 5.2, 10.0 .... This corresponds to the known distances of the planets and Asteroid belt measured in Astronimical Units; .39, .72, 1.00, 1.52, 2.77, 5.20, 9.54,.... May be coincidental or due to as yet unexplored harmonic wave function in the accretion disc of new solar systems.
Bolide:-
A meteor which glows brightly as it enters the Earth's atmosphere, sometimes exploding.
Bolometer:-
An extremly sensitive instrument for measuring faint radiation over a very broad range of wavelengths.
Bolometric magnitude:-
Total amount of energy emitted by a star.
Carbon-cycle :-
Terraforming cycle by organic lifeforms which have over millions of years extracted billions of tons of carbon from Earth's atmosphere, locking it up in coal and oil deposits and in the process making the Earth capable of sustaining intelligent life :)
Reverse cycle which involves burning of fossil fuels, combining carbon with oxygen to form Co2 and Co, (which are both greenhouse gases) trapping solar radiation and heating the planet, creating warmer seas, more turbulent weather systems, loss of species, destruction of environments suited to intelligent lifeforms :(
Carbon-nitrogen cycle :-
A series of reactions inside a star, involving carbon and nitrogen as catalysts, causing hydrogen to be converted to helium, releasing vast amounts of energy.

Cassegrain reflector :- A reflecting telescope which shortens the overall length of the instruement by reflecting the light from the object onto a secondary convex mirror and back through the center of the main mirror to the eyepiece.

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END :-Cassegrain reflector
More to come :)