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Astronomers measure the angular separation of two stars by imagining two lines through the centre of the Earth, each intersecting one of the stars.
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Astronomers and measure
Astronomers also measure the apparent size of objects as an angular diameter.
Astronomers had believed for some time that parallax would provide the first accurate measurement of interstellar distances — in fact, in the 1830s there was a fierce competition between astronomers to be the first to measure a stellar parallax accurately.
Astronomers use the principle of parallax to measure distances to celestial objects including to the Moon, the Sun, and to stars beyond the Solar System.
Astronomers typically measure the distances between neighbouring galaxies and galaxy clusters in megaparsecs.
Astronomers typically use gigaparsecs to measure large-scale structures such as the size of, and distance to, the CfA2 Great Wall ; the distances between galaxy clusters ; and the distance to quasars.
Astronomers have used the Bortle Dark-Sky Scale to measure skyglow ever since it was published in Sky & Telescope magazine in February 2001.
Astronomers can now measure differences as small as one-hundredth of a magnitude.
Astronomers and separation
Astronomers of the era expected that changes over time in the apparent separation and relative location of these stars would provide evidence for both the proper motion of stars and, by means of parallax shifts in their separation, for the distance of stars from the Earth ( a method first suggested by Galileo Galilei ).
Astronomers and two
Astronomers estimated that the visible fragments of SL9 ranged in size from a few hundred metres to two kilometres across, suggesting that the original comet may have had a nucleus up to acrosssomewhat larger than Comet Hyakutake, which became very bright when it passed close to the Earth in 1996.
Astronomers do not know if the collision was simply a glancing blow or a prelude to a full-on merger, which would end with the two galaxies incorporated into one larger, probably elliptical galaxy.
However, two Astronomers Royal had recently died in quick succession and Maskelyne was appointed to the position soon after his return to England.
Astronomers were able to discover that IRS2 is in fact a twin system composed of two almost equally massive stars.
On March 22, 2005, Astronomers using NASA's Spitzer Space Telescope took advantage of this fact to directly capture the infrared light of two previously detected planets orbiting outside our solar system.
* October 31 – Astronomers announce the discovery of two additional moons orbiting Pluto, Nix and Hydra.
" Astronomers have noted that the observation may have been of a reflection of a bright star which lies two degrees to the north of NGC 56's location.
Astronomers and stars
Astronomers were surprised by these " hot Jupiters ," since theories of planetary formation had indicated that giant planets should only form at large distances from stars.
Astronomers preferentially use the HD designation of a star, as that catalogue also gives spectroscopic information, but as the Durchmusterungs cover more stars they occasionally fall back on the older designations when dealing with one not found in Draper.
Astronomers found that it was more accurate to establish time by observing stars as they crossed a meridian rather than by observing the position of the Sun in the sky.
Astronomers have directly observed protoplanetary disks, brown dwarfs, intense and turbulent motions of the gas, and the photo-ionizing effects of massive nearby stars in the nebula.
Astronomers have long thought it was quite likely that many undiscovered dwarf stars exist within 20 light years of Earth, as stellar population surveys show the count of known nearby dwarf stars to be lower than otherwise expected and these stars are dim and easily overlooked.
Astronomers theorize that they may be a rare type of x-ray emitting binary stars or intermediate-mass black holes.
Astronomers using the Hale Telescope have discovered distant objects at the edges of the known universe called quasars and have given us the first direct evidence of stars in distant galaxies.
Astronomers had made careful photometric measurements of several stars known to be orbited by planets, in the hope that they might observe a dip in brightness caused by the transit of the planet across the star's face.
Astronomers observe a wide range of astronomical sources, including high-redshift galaxies, AGNs, the afterglow from the Big Bang and many different types of stars and protostars.
Astronomers have been discovering " extrasolar " planets ( planets that orbit stars other than the Sun ) the last few years.
Astronomers had made careful photometric measurements of several stars known to be orbited by planets, in the hope that they might observe a dip in brightness caused by the transit of the planet across the star's face.
Astronomers study the actual stars and planets, but have found no evidence supporting astrological theories.
Astronomers divide these stars into classes 0, I, II and III, according to how much infrared radiation the stars give off.
Astronomers at the Space Telescope Science Institute in Baltimore, Maryland and the European Space Agency in discerned the distance by observing Cepheid variable stars within I Zwicky 18.
Astronomers took careful note of " guest stars ", which suddenly appeared among the fixed stars.
Astronomers and by
Astronomers use the Julian calendar for years before 1582, including this year 0, and the Gregorian calendar for years after 1582 as exemplified by Jacques Cassini ( 1740 ), Simon Newcomb ( 1898 ) and Fred Espenak ( 2007 ).
* Star with Midriff Bulge Eyed by Astronomers, JPL press release, July 25, 2001.
Astronomers believe that the matter composing the Oort cloud formed closer to the Sun and was scattered far out into space by the gravitational effects of the giant planets early in the Solar System's evolution.
Astronomers speculate that this phenomenon is caused by the shock wave from a supernova.
Astronomers can determine the mass, age, chemical composition and many other properties of a star by observing its spectrum, luminosity and motion through space.
* Astronomers have reported that spectral class T brown dwarves ( the ones with the coolest temperatures ) are colored magenta because of absorption by sodium and potassium atoms of light in the green portion of the spectrum.
Astronomers responded by introducing the deferent and epicycle, which caused a planet to vary its distance.
From " Dante and the Early Astronomers " by M. A. Orr, 1913.
The Jalali calendar was introduced by Omar Khayyám alongside other Mathematicians and Astronomers in Nishapur, today it is one of the oldest calendars in the world as well as the most accurate solar calendar in use today.
On Monday 14 April 2008, Cheshire's 106. 9 Silk FM unveiled to its listeners their own campaign song to save Jodrell Bank, entitled " The Jodrell Bank Song " and sung by a group dubbed " The Astronomers ".
Astronomers have been conducting surveys to locate the NEOs, many ( as of early 2007 ) funded by NASA's Near Earth Object ( NEO ) program office as part of their Spaceguard program.
In Astronomers, Scribes, and Priests: Intellectual Interchange between the Northern Maya Lowlands and Highland Mexico in the Late Postclassic Period, edited by Gabrielle Vail and Christine Hernandez, pp. 77 – 114.
Astronomers first began to suspect that the Milky Way is a barred spiral galaxy in the 1990s .< ref > Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005 which showed the galaxy's central bar to be larger than previously suspected.
Astronomers who believed quasars were not at cosmological distances argued that the Eddington luminosity set limits on how distant the quasars could be since the energy output required to explain the apparent brightness of cosmologically-distant quasars was far too high to be explainable by nuclear fusion alone.
Astronomers anticipate an increase of activity in the region of the black hole, giving opportunity for further study, in mid-2013, as it is expected that a large gas cloud will be disrupted by close approach.
These productions include the official International Year of Astronomy ( IYA2009 ) planetarium show " We are Astronomers " which was funded by the UK Science and Technology Facilities Council ( STFC )
Astronomers announce this as evidence that the theory of the cosmological constant proposed, but later discarded, by Einstein may have been right after all.
Astronomers observe the sky for X-rays emitted by infalling matter to detect black holes.
Astronomers were able to distinguish the warmest parts of the gas heated by the violent shocks and found that they form a complex double-bubble shape.
0.287 seconds.