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Astronomy On Mercury
Astronomy on Mercury is the sky as viewed from the planet Mercury (planet), Mercury. Because Mercury only has Atmosphere of Mercury, a thin atmosphere, the sky will be black. Sun Due to the proximity of Mercury to the Sun, Mercury on average receives an energy flux from the Sun that is about 7 times the solar constant, but may reach nearly 11 times at maximum and about 4.5 times at minimum. The Sun will have an angular diameter of 1.733 to 1.142°. From perihelion to aphelion, the size of the Sun increases almost 66%, as does the brightness. This is due to the high Orbital eccentricity, eccentricity of Mercury's orbit around the Sun. Due to tidal locking, three rotations of Mercury, is equal to two revolutions around the Sun. Because of this, the method of plotting the Sun's position at the same time each day would yield only a single point. However, the equation of time can still be calculated for any time of the year, so an analemma can be graphed with this information. The res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (planet)
Mercury is the first planet from the Sun. It is a rocky planet with a trace atmosphere. While it is the List of Solar System objects by size, smallest and least massive planet of the Solar System, its surface gravity is slightly higher than that of Mars. The surface of Mercury is similar to Earth's Moon, heavily Impact crater, cratered, with expansive rupes system, generated from thrust faults, and bright ray systems, formed by ejecta. Its largest crater, Caloris Planitia, has a diameter of , which is about one-third the diameter of the planet (). Being the most inferior planet, inferior orbiting planet it appears in Earth's sky, always close to the Sun, either as a "morning star" or an "evening star". It stays most of the time the closest to all other planets and is the planet with the highest delta-v needed to travel to from all other planets of the Solar System. Mercury's sidereal year (88.0 Earth days) and sidereal day (58.65 Earth days) are in a 3:2 ratio. This relation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transit (astronomy)
In astronomy, a transit (or astronomical transit) is the passage of a astronomical object, celestial body directly between a larger body and the observer. As viewed from a particular vantage point, the transiting body appears to move across the face of the larger body, eclipse, covering a small portion of it. The word "transit" refers to cases where the nearer object apparent size, appears smaller than the more distant object. Cases where the nearer object appears larger and completely hides the more distant object are known as occultation, ''occultations''. However, the probability of seeing a transiting planet is low because it is dependent on the alignment of the three objects in a nearly perfectly straight line. Many parameters of a planet and its parent star can be determined based on the transit. In the Solar System One type of transit involves the motion of a planet between a Earth, terrestrial observer and the Sun. This can happen only with inferior and superior pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Culmination
In observational astronomy, culmination is the passage of a celestial object (such as the Sun, the Moon, a planet, a star, constellation or a deep-sky object) across the observer's local meridian. These events are also known as meridian transits, used in timekeeping and navigation, and measured precisely using a transit telescope. During each day, every celestial object appears to move along a circular path on the celestial sphere due to the Earth's rotation creating two moments when it crosses the meridian. Except at the geographic poles, any celestial object passing through the meridian has an upper culmination, when it reaches its highest point (the moment when it is nearest to the zenith), and nearly twelve hours later, is followed by a lower culmination, when it reaches its lowest point (nearest to the nadir). The time of ''culmination'' (when the object culminates) is often used to mean upper culmination. An object's altitude (''A'') in degrees at its upper culmin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidereal Time
Sidereal time ("sidereal" pronounced ) is a system of timekeeping used especially by astronomers. Using sidereal time and the celestial coordinate system, it is easy to locate the positions of celestial objects in the night sky. Sidereal time is a "time scale that is based on Earth's rate of rotation measured relative to the fixed stars". A sidereal day (also known as the sidereal rotation period) represents the time for one rotation about the planet axis relative to the stars. Viewed from the same location, a star seen at one position in the sky will be seen at the same position on another night at the same time of day (or night), if the day is defined as a sidereal day. This is similar to how the time kept by a sundial (Solar time) can be used to find the location of the Sun. Just as the Sun and Moon appear to rise in the east and set in the west due to the rotation of Earth, so do the stars. Both solar time and sidereal time make use of the regularity of Earth's rot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imaginova
Imaginova Corporation is a U.S. digital commerce company based in Watsonville, California. The company, which was started in 1999 as "Space.com" by CNN business anchor Lou Dobbs, later became known as Space Holdings Corp. Dan Stone became president, chief executive officer and a board member in 2002 and renamed the company to Imaginova in 2004. The company sold its consumer businesses to TechMediaNetwork, formally TopTenReviews, in 2009. ''Imaginova'' promotes itself as the preeminent destination for the “intellectually curious.” It comprises the following E-Commerce retailer: space * LiveScienceStore.com LiveScienceStore.com ''Imaginova'' previously owned Orion Telescopes & Binoculars until Orion was repurchased by its employees in November 2017. ''Imaginova'' previously owned SpaceNews until it was sold to Pocket Ventures, LLC. in 2012. ''Imaginova'' is a news provider, via the Imaginova Network of media properties, and syndicates its original content to the followi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Omicron Draconis
Omicron Draconis (Latinised as ο Draconis, abbreviated to ο Dra) is a giant star in the constellation Draco (constellation), Draco located 322.93 light years from the Earth. Its path in the night sky is circumpolar star, circumpolar for latitudes greater than 31o north, meaning the star never rises or sets when viewed in the night sky. This is a single-lined spectroscopic binary system, but the secondary has been detected using interferometry. It is an RS Canum Venaticorum variable system with eclipses. The total amplitude of variation is only a few hundredths of a magnitude. The secondary star is similar to the Sun, presumably a main sequence star, while the primary is a giant star 25 times larger than the Sun and two hundred times more luminous. Identities as pole star Omicron Draconis can be considered the north pole star of Mercury (planet), Mercury, as it is the closest star to Mercury's north celestial pole. In addition to that, this star is currently the M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polaris
Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris (Latinisation of names, Latinized to ''Alpha Ursae Minoris'') and is commonly called the North Star or Pole Star. With an apparent magnitude that fluctuates around 1.98, it is the brightest star in the constellation and is readily visible to the naked eye at night. The position of the star lies less than angular distance, 1° away from the north celestial pole, making it the current northern pole star. The stable position of the star in the northern celestial hemisphere, Northern Sky makes it useful for celestial navigation, navigation. As the closest Cepheid variable its distance is used as part of the cosmic distance ladder. The revised ''Hipparcos'' stellar parallax gives a distance to Polaris of about , while the successor mission Gaia (spacecraft), ''Gaia'' gives a distance of about . Although appearing to the naked eye as a single point of light, Polar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Pictoris
Alpha Pictoris (α Pic, α Pictoris) is the brightest star in the southern constellation of Pictor. It has an apparent visual magnitude of 3.27, which is bright enough to be viewed from urban areas in the southern hemisphere. This is actually a binary star system, whose components complete an orbit every three years and seven months. It is close enough for its distance to be measured using parallax shifts, which yields a value of roughly from the Sun, with a 5% margin of error. Alpha Pictoris has the distinction of being the south pole star of the planet Mercury. Properties With an estimated age of 660 million years, the primary component is a relatively young Lambda Boötis star. The stellar classification of shows this peculiarity, with the kA6 notation indicating weaker than normal calcium K-lines in the spectrum. The 'n' following the main sequence luminosity class of V indicates the absorption lines in the spectrum are broad and nebulous. This is caused by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pole Star
A pole star is a visible star that is approximately aligned with the axis of rotation of an astronomical body; that is, a star whose apparent position is close to one of the celestial poles. On Earth, a pole star would lie directly overhead when viewed from the North or the South Pole. Currently, Earth's pole stars are Polaris (Alpha Ursae Minoris), a bright magnitude 2 star aligned approximately with its northern axis that serves as a pre-eminent star in celestial navigation, and a much dimmer magnitude 5.5 star on its southern axis, Polaris Australis (Sigma Octantis). From around 1700 BC until just after 300 AD, Kochab (Beta Ursae Minoris) and Pherkad (Gamma Ursae Minoris) were twin northern pole stars, though neither was as close to the pole as Polaris is now. History In classical antiquity, Beta Ursae Minoris (Kochab) was closer to the celestial north pole than Alpha Ursae Minoris. While there was no naked-eye star close to the pole, the midpoint between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zodiacal Light
The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direction in a roughly triangular shape along the zodiac, and appears with less intensity and visibility along the whole ecliptic as the zodiacal band. Zodiacal light spans the entire sky and contributes to the natural light of a clear and moonless night sky. A related phenomenon is ''gegenschein'' (or ''counterglow''), sunlight backscattered from the interplanetary dust, which appears directly opposite to the Sun as a faint but slightly brighter oval glow. Zodiacal light contributes to the natural light of the sky, though since zodiacal light is very faint, it is often outshone and rendered invisible by moonlight or light pollution. The interplanetary dust in the Solar System forms a thick, pancake-shaped cloud called the zodiacal cloud wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
