相关论文: Magnitude systems in old star catalogues
Historical star magnitudes from catalogues by Ptolemy (137 AD), as-Sufi (964) and Tycho Brahe (1602/27) are converted to the Johnson V-mag scale and compared to modern day values from the HIPPARCOS catalogue. The deviations (or "errors")…
In late antiquity and throughout the middle ages, the positions of stars on the celestial sphere were obtained from the star catalogue of Ptolemaios. A catalogue based on new measurements appeared in 1437, with positions by Ulugh Beg, and…
The comparison of visual magnitudes of stars compiled in old catalogues is expected to yield information about their long-term magnitude variations. In seven old catalogues whose historical data have been intensively compared, 2123 sampled…
Three pre-telescopic star catalogues contain about a thousand star magnitudes each (with magnitudes 1, 2, 3, 4, 5, and 6), with these reported brightnesses as the original basis for what has become the modern magnitude scale. These…
The catalogue by Johannes Hevelius with the positions and magnitudes of 1564 entries was published by his wife Elisabeth Koopman in 1690. We provide a machine-readable version of the catalogue, and briefly discuss its accuracy on the basis…
Magnitude is an isometric invariant for metric spaces that was introduced by Leinster around 2010, and is currently the object of intense research, since it has been shown to encode many known invariants of metric spaces. In recent work,…
The Copernican Principle (which says the Earth and sun are not unique) should have observational consequences and thus be testable. Galileo Galilei thought he could measure the true angular diameters of stars with his telescope; according…
We describe a modification of the usual definition of astronomical magnitudes, replacing the usual logarithm with an inverse hyperbolic sine function; we call these modified magnitudes `asinh magnitudes'. For objects detected at…
Tycho Brahe completed his catalogue with the positions and magnitudes of 1004 fixed stars in 1598. This catalogue circulated in manuscript form. Brahe edited a shorter version with 777 stars, printed in 1602, and Kepler edited the full…
The notion of the magnitude of a metric space was introduced by Leinster in [8] and developed in [10], [9], [11] and [16], but the magnitudes of familiar sets in Euclidean space are only understood in relatively few cases. In this paper we…
The physiology of the dark adaption process of the eye is revisited from an astronomical point of view. A new method for the magnitude estimation of a star is presented. It is based upon the timing of the physiological cycle of the…
The uncertainty about the relationships between the star catalogue contained in the Almagest (books VII-VIII) and the catalogue of Hipparchus dates back to the origins of modern astronomy. The fact that Hipparchus' catalogue was lost and…
Near the end of the 16th century Wilhelm IV, Landgraf von Hessen-Kassel, set up an observatory with the main goal to increase the accuracy of stellar positions primarily for use in astrology and for calendar purposes. A new star catalogue…
A new musical scale devised by the author, based on natural logarithms, is described. Most of the logarithmic pitches bear no correspondence to the twelve tones of the ancient tuning system attributed to Pythagoras, based on ratios of whole…
Current catalogues of open clusters are rather heterogeneous and incomplete lists of clusters than true catalogues. Before there has been no attempts of automatic search for open clusters in huge photometric catalogues using homogeneous…
A new version of the Catalog containing Sloan magnitudes for the brightest stars is presented. The accuracy of the data indicates that the Catalog is a reliable source of comparison star magnitudes for astronomical photometry. Version 2…
In 1785 astronomer William Herschel mapped out the shape of the Milky Way star system using measurements he called "star-gages." Herschel's star-gage method is described in detail, with particular attention given to the assumptions on which…
De Houtman in 1603, Kepler in 1627 and Halley in 1679 published the earliest modern catalogues of the southern sky. We provide machine-readable versions of these catalogues, make some comparisons between them, and briefly discuss their…
The origin and calibration of the maximum absolute magnitude relation with decline time (MMRD) for novae, first derived by Zwicky (1936) empirically validated by McLaughlin (1940) and widely used to estimate distances to classical novae and…
Magnitude is a real-valued invariant of metric spaces, analogous to the Euler characteristic of topological spaces and the cardinality of sets. The definition of magnitude is a special case of a general categorical definition that clarifies…