Glossary of Astronomical Terms
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AAVSO Photometric All Sky Survey - A photometric calibration of the entire sky, mag 8 - 17 approximately, using two 8-inch astrograph relectors on a single Paramount with Apogee cameras and filterwheels, mag 8-17.
adaptive optics (AO) - A telescopic optical system that can
change the shape of a secondary mirror to correct the distortion of
incoming light waves.
air mass -
angular distance - the distance between two objects measured as an angle.
Astrophotography and Digital Imaging Terms - A Glossary of Astrophotography and Digital Imaging Terms developed by noted astrophotographer and author Jerry Lodriguss.
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blueshift - the shift of light emitted from an approaching source towards the blue end of the visible spectrum.
Bright star monitor BSM - A telescope/camera system operated by AAVSO in New Mexico that monitors nightly a list of selected stars brighter than around tenth magnitude.
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Catalogs - Compilations of data on astronomical objects, generally organized by object name, type and location. (This entry is under development)
- ACT A catalog compiled by the US
Naval Observatory (USNO), to provide accurate proper motions for the
majority of stars in the Tycho Catalogue.
- ADS Aitken Double Star Catalog
- AGK3
- Astrographic Catalogue Carte du Ciel
- BD Bonner Durchmusterung
- Catalog of Principal Galaxies 1999
- CD Cordoba Durchmusterung
- CPD Cape Photographic Durchmusterung
- DSS Digital Sky Survey
- EVS
- FK Fundamental Katalog
- Franklin-Adams Charts
- GC
Boss General Catalog
- Gliese Catalog
- GSC I Guide Star Catalog I
- GSC II Guide Star Catalog II
- GCVS General Catalog of Variable Stars
- Globular Clusters of the Milky Way
- Groombridge Catalog
- HD Henry Draper Catalog
- HIP Hipparcos Catalog
- HR Harvard Revised Photometry Catalog
- HST
- IC Index Catalog
- Lynd's Catalog of Bright Nebulae
- Messier Catalog
- NCSVS New Catalog of Suspected Variable Stars
- NGC New General Catalog of Nebulae and Star Clusters
- NGC 2000,0 is a compilation of the New General Catalog (NGC), the
Index Catalog (IC I) and the Second Index Catalog (IC II).
- NSV
- Open Cluster Data 5th Edition
- PGC 1999
- POSS Palomar Observatory Sky Survey
- SAC 7.2
- SAO Smithsonian Astrophysical Observatory Catalog
- SDSS Sloan Digital Sky Survey
- Shapely-Ames Catalog
- The Sharpless
Catalog A nebula catalog published by
Stewart Sharpless.
- Southern Sky Survey
- SRS Southern Reference Stars
- Strasbourg ESO Catalog of Galactic Planetary Nebulae
- Third Reference Catalog of Bright Galaxies
- TYC-2 Tycho Catalog
- USNO-A2.0
- USNO-SA2.0
- WDS Double Star
- WVDS Washington Visual Double Star Catalog 2000
- Yale Catalog of Bright Stars 5th Edition
- Zwicky Catalog Catalogue of Galaxies and Clusters of
Galaxies
celestial equator - An arc in the sky obtained by projecting a plane containing the Earth's equator onto the celestial sphere.
Central Bureau for Astronomical Telegrams CBAT - A part of the International Astronomical Union IAU responsible for the dissemination of transient astronomical events.
color index
cross-quarter days - The days approximately half way between
the solstices and equinoxes. Marked the beginning of the seasons
In ancient times.
Candelmas - February 2 - Spring
Beltane - May 1 - Summer
Lammas - August 1 - Fall
Halloween - October 31 or Martinmas - November 11 -
Winter
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declination - The celestial equivalent of latitude. It is measured in degrees North or South of the celestial equator.
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extinction
- first order - corrects for air mass
- second order - corrects for color
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Galaxy - A galaxy is usually defined as a group of hundreds of millions or even billions of stars along with huge quantities of gas and dust, all held together by the force of gravity. Sometimes the definition also includes the notion that a counteraction centrifugal force created by the rotation of the galaxy keeps the componenets of the galaxy from collapsing upon themselves.
Gamma-ray burst GRB - A narrow beam of intense gamma radiation lasting from a few milliseconds up to an hour. This is the most intense radiation know to exist in the universe and is associated with supernova events in distant galaxies. So far, all observed GRBs have originated outside our galaxy.
Gould's Belt - A 50 million year old belt of blue stars surrounding the sun and tilted about 20 degrees above the galactic plane in the direction of Sagittarius and below the galactic plane in the direction of Orion. The center of Gould's Belt, an ellipse of 1500 by 2500 light years, lies about 600 hundred light years from the Sun in the direction of Perseus near Alpha Persei. Star associations Orion, Perseus, Lacerta, Cepheus, Scorpius-Centaurus and Vela lie within Gould's Belt. The Pleiades is older that Gould's Belt and, thus, is not a part of it but the gas and dust that surrounds the Pleiades does come from Gould's belt.
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Kepler - Johannes Kepler (1571 - 1630) A mathematician who developed three general principles describing planetary motion about the Sun:
Kepler's First Law: - The orbit of a planet about the sun is
an ellipse with the sun at one focus.
Kepler's Second Law: - A line joining a planet and the sun will
sweep out equal areas in equal intervals of time.
Kepler's Third Law: - The square of the sidereal period, in
years, of a planet is directly proportional to the cube of the semimajor
axis, in AU, of its orbit.
Kepler developed these principles through a thorough study of voluminous
data on planetary positions recorded by astronomer Tycho Brahe but never
developed a theory to explain why the planets behaved this way.
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LAGEOS - Laser Geodynamic Satellite. A satellite launched in 1974
into a very precise orbit about the Earth. This satellite is designed to
reflect laser beams from ground transmitters to provide precise
measurements of the separation of the ground stations over time. Because
the life expectancy of the satellite is approximately 8 million years,
the satellite bears a plaque of information for future geologists.
light pollution - Unwanted illumination of the night sky by city,
street or security lights making astronomical observation difficult. In
astrophotography, sodium light will give a pink cast to exposures;
mercury light will give a grey-green cast to exposures.
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magnitude
absolute -
apparent -
differential -
extraterrestrial -
instrumental -
normalized -
photometric -
raw - equal to -2.5 log(total pixel ADU count)
reference -
standard -
Mercury - Mercury's weak magnetic field is probably generated by
condensing iron molecules that are falling towards an inner core from an
iron-sufur mixture that comprises the outer core.
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parsec - photometry - The use of photographic equipment to measure and record the changing brightness over time of celestial objects.
- absolute -
- all-sky -
- differential -
- ensemble -
- single channel -
- synthetic -
The Pinwheel Galaxy - M33 - A member of the local group of
about 40 galaxies. It is the most distant member from the Milky Way.
Pioneer 10, 11 - Launched 1971 and 1972. First interstellar space
vehicles. Each carrier a plaque with information about ourselves should
any form of intelligent life intercept one of these vehicles.
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redshift - the shift of light emitted from a receding source towards the red end of the visible spectrum.
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Saturn - Storm systems on Saturn can be thousands of miles
across, endure for many months and have lightning discharges thousands
of time stronger than those here on Earth.
- Saturn's moon Enceladus has water plumes jetting into space from areas
near its southern pole that contain organic compounds.
-Saturn's moon Titan, the second largest moon in our solar system, is
encased in a shroud of smog - 360 miles thick and composed of 95%
nitrogen and 5% methane, cyanide and hydrocarbons.
Seeing - Refers to the stability or steadiness of the atmosphere
on a scale of 1 (extremely unstable) to 5 (extremely stable). Unstable
air shifts the light that passes through it. To an observer, the poorest
seeing (1) makes stars and planets appear to jitter, dance or boil to
the point that they look like shattered blobs of light. The same stars
and planets under the best seeing (5) appear as steady sources of light
with no jitter.
standard distance -
Standard Model of the Universe - A theory that organizes the
makeup of the universe into fundamental forces and particles.
Note: Need to work on indenting lists.
- Fundamental Forces
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- Gravity - Not included?
- Fundamental Particles
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Landolt -
M67 -
star
comparison -
program -
standard -
star types - (Under develoment)
-Mira
-CV
-semiregular
-semidetached algol eclipsiing binary
-cephid
-RR Lyra
-TTau/YSO
System
broadband -
standard -
Johnson/Cousins -
SDSS -
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Torino Scale - A system of assigned numbers from zero to ten
to denote the probability of a space object colliding with earth. Zero
means no probability; ten means a collision is certain. The scale was
devised by Richard Binzel, a scientist at MIT.
transformation
transformation coefficients
Transparency - Refers to clarity or darkness of the sky. The
value assigned to transparency is the highest magnitude star an observer
can see with the unaided eye at about 45 degrees above the horizon. A
value of 1 (first magnitude) would be very poor while a value of 7
(seventh magnitude) would be exceptionally good.
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Variable Stars -
Link to Variable Star Classifications
Venus - Second Planet from the sun and about 30% closer than
Earth. Venus is only 26 million miles from Earth when positioned between
Earth and the Sun, about 100 times farther from Earth than the Moon.
Greatest elongation for Venus is about 47 degrees from the Sun.
Venus Express - European Space Agency spacecraft launched
November 2005 and inserted into a 24-hour polar orbit around Venus in
April 2006. Expected to return data on atmosphere, clouds, plasma
environment, surface characteristics, and mapping through May 2009.
Voyager - Two space vehicles launched into space in 1977. Each
contained information about ourselves in various forms. The development
of the information placed on the space vehicles is documented by Carl
Sagan in his book Murmurs of Earth published in 1978.
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W28 - A program operated by AAVSO and Tom Krajci in New Mexico for time series exposures of selected stars using an 11" Celestron.
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zero point -
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