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An online star chart; Monthly sky maps for every location on Earth Archived 2007-09-13 at the Wayback Machine; The Evening Sky Map – Free monthly star charts and calendar for northern hemisphere, southern hemisphere, and equatorial sky watchers. Sky Map Online – Free interactive star chart (showing over 1.2 million stars up to magnitude 12)
Celestial cartography, [1] uranography, [2] [3] astrography or star cartography [citation needed] is the aspect of astronomy and branch of cartography concerned with mapping stars, galaxies, and other astronomical objects on the celestial sphere. Measuring the position and light of charted objects requires a variety of instruments and techniques.
An occulting light is a rhythmic light in which the duration of light in each period is longer than the total duration of darkness. In other words, it is the opposite to a flashing light where the total duration of darkness is longer than the duration of light. It has the appearance of flashing off, rather than flashing on.
A-type star In the Harvard spectral classification system, a class of main-sequence star having spectra dominated by Balmer absorption lines of hydrogen. Stars of spectral class A are typically blue-white or white in color, measure between 1.4 and 2.1 times the mass of the Sun, and have surface temperatures of 7,600–10,000 kelvin.
Arcturus is the brightest star in the constellation of Boötes. With an apparent visual magnitude of −0.05, Arcturus is the brightest star in the northern celestial hemisphere and the fourth-brightest star in the night sky, [14] after Sirius (−1.46 apparent magnitude), Canopus (−0.72) and α Centauri (combined
While light from stars and other astronomical objects is likely to twinkle, [10] twinkling usually does not cause images of planets to flicker appreciably. [ 11 ] [ 12 ] Stars twinkle because they are so far from Earth that they appear as point sources of light easily disturbed by Earth's atmospheric turbulence, which acts like lenses and ...
Like the other stars in the group, it is a main sequence star, as the Sun is, although somewhat hotter, brighter and larger. Phecda is located in relatively close physical proximity to the prominent Mizar–Alcor star system. The two are separated by an estimated distance of 8.55 ly (2.62 pc); much closer than the two are from the Sun.
The other two cover the equatorial region of the celestial sphere, from the declination of 30° south to 30° north. The two equatorial charts are mercator projections, one for the eastern hemisphere of the celestial sphere and one for the western hemisphere. Note that unlike familiar maps, east is shown to the left and west is shown to the right.