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 had expected to see the fireballs from the impacts, but did not have any idea in advance how visible the atmospheric effects of the impacts would be from Earth.

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 before Eddy had also named the period after the solar astronomer Edward W. Maunder ( 1851 – 1928 ) who studied how sunspot latitudes changed with time.

However, two Astronomers Royal had recently died in quick succession and Maskelyne was appointed to the position soon after his return to England.

Astronomers think that the sun had about 70 – 75 % of the present luminosity, yet temperatures appear to have been near modern levels even within 500 Ma of Earth's formation, which is puzzling ( the faint young sun paradox ).

Astronomers analysing old data found that Ulysses ' instruments had detected a large drop in the number of protons passing, as well as a change in the direction and strength of the local magnetic field.

Astronomers assumed that there was only one body in that orbit, and accordingly had difficulty determining their orbital characteristics.

" Astronomers in Bochum, West Germany, had observed a bright glow on the lunar surface — the same sort of eerie luminescence that has intrigued moon watchers for centuries.

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 who had been studying the planet Venus chose Rittenhouse to study the transit path of Venus in 1769 and its atmosphere.

Astronomers had to stare for hours through their telescopes, waiting for a moment of still air when the image was clear, and then draw a picture of what they had seen.

Norman Sperling is a recipient of the National Service Award by the Western Amateur Astronomers, and had been recognized " For special and meritorious service for his unusual dedication and service to the astronomical community in all areas of astronomy " by the Astronomical Association of Northern California.

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 had long wished for a way to photograph large swathes of the sky quickly for the purpose of surveying the visible contents of the universe and seeing large-scale structures.

Astronomers had to make thousands of such calculations, and because the best method of multiplication available was long multiplication, most of this time was spent taxingly multiplying out products.

Astronomers inferred that the star had been a red supergiant, and had shed a large amount of matter into space, before evolving into a blue supergiant and exploding.

When Pluto was first discovered, it was initially known as Planet X. Astronomers had been searching for another planet past Neptune, hoping to solve the dilemma of its rather irregular orbit.

Astronomers have long believed that the Magellanic Clouds have orbited the Milky Way at approximately their current distances, but evidence suggests that it is rare for them to come as close to the Milky Way as they are now.

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 have dubbed this object as the Twin Jet Nebula because of the polar jets believed to cause the shape of the lobes.

Astronomers at that time believed in the Kant-Laplace hypothesis, which stated that the farthest planets from the sun are the oldest — therefore Mars was more likely to have advanced civilizations than Venus.

Astronomers of his time believed the universe to be heliocentric, a belief they held until the 1920s.

Astronomers originally supposed that the entire trans-Neptunian population would show a similar red surface colour, as they were believed to have originated in the same region and subjected to the same physical processes.

Astronomers use astrometric techniques for the tracking of near-Earth objects.

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 ).

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 never preposed seriously to replace our era with their astronomical era ( which for that matter coincides exactly with the Christian era where it concerns the calendar years after the year 4 ).

Astronomers estimate that the cluster will survive for about another 250 million years, after which it will disperse due to gravitational interactions with its galactic neighborhood.

* Adventures in Deep Space: Challenging Observing Projects for Amateur Astronomers.

* 2002 — Astronomers at the Max Planck Institute for Extraterrestrial Physics present evidence for the hypothesis that Sagittarius A * is a supermassive black hole at the center of the Milky Way galaxy

Astronomers have speculated that either intense star formation regions or active galactic nuclei ( which contain supermassive black holes ) may be responsible for the intense dust heating that produces this emission, although the general consensus is that both may be present in most ULIRGs.

The Amateur Astronomers Association of New York meets there one night a month from May to December for observing.

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.

Dobson optimized the design for visual observation of faint objects such as star clusters, nebulae, and galaxies ( what Amateur Astronomers call deep sky objects ).

Astronomers observe the sky for X-rays emitted by infalling matter to detect black holes.

Astronomers submit proposals for peer review to gain access to the telescopes which are scheduled every night of the year for observations ( with the exception of Christmas and New Year's Eve ).

Astronomers in societies which have alternate traditional names for the planets may use those names in scientific discourse.

Astronomers follow the same calendar conventions that are accepted in the world community: They use the Gregorian calendar for events since its introduction on ( or later, depending on country ), and the Julian calendar for events before that date.

Astronomers now see elliptical galaxies as some of the most evolved systems in the universe.

Astronomers initially ruled out the possibility that some of the point-like objects are white dwarfs, because they are too blue to be consistent with theories of white dwarf evolution prevalent at the time.

Astronomers theorize that the gravity of one star pulls some of the gas from the surface of the other and flings it into a thin, dense disk extending into space.

And even among those Stars which are reckoned of the brightest Class, there appears a Variety of Magnitude ; for Sirius or Arcturus are each of them brighter than Aldebaran or the Bull's Eye, or even than the Star in Spica ; and yet all these Stars are reckoned among the Stars of the first Order: And there are some Stars of such an intermedial Order, that the Astronomers have differed in classing of them ; some putting the same Stars in one Class, others in another.