... The Round Earth . ... Aristarchus around 270 BC derived the Moon's distance from the duration of a lunar eclipse (Hipparchus later found an independent method). ... Let R be the radius of that circle and T the time it takes the Moon to go around once, about one month. ... Viewed from Earth, a "new Moon" (occuring between the time a thin crescent is last seen before sunrise and the time one is seen shortly after sunset) happens when the Moon in its apparent motion around the sky overtakes the Sun. ...

... Hubble Detects Faster-Than-Light Motion in Galaxy M87 . ... Click on image for larger version. (100kB GIF) Sequence of Hubble images showing apparent motion at six times the speed of light in the galaxy M87. ... The slanting lines track the moving features, and the speeds are given in units of the velocity of light ``c." The images were made between 1994 and 1998 with the Faint Object Camera on the Hubble Space Telescope. ... PHOTO CREDIT: John Biretta, Space Telescope Science Institute. ...

Compilation of distance measurements . HyperLeda home | Documentation | Search by name | Search near a position | ... SQL Search | Search an object in the distance catalogue . This catalog (table a007 in the database) presents the compilation of published distance mesurements using photometric distance indicators. Photometric modulus. Error of modulus measurement. The method used to determine the distance is coded for each measurement as follow: . HyperLeda . ...

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... This distance is equivalent to 3.26 light years. ... The Universe was now a large place and the intrinsic energy output of the stars had to be huge in order that their light could reach us. ... Newton implicitly assumes space is flat . ... An Orbit in Curved Space This is a prediction made by General Relativity and confirmed by direct observation of Mercury. The Ant Universe in Flat Space . ... Hubble noticed a correlation between recessional velocity and distance. ...

... Posts tagged ?Mahalanobis distance? ... It bears the name of its inventor, Prasanta Chandra Mahalanobis. ... Therefore, under different names, I believe that the Mahalanobis distance is frequently applied in exploring and analyzing astronomical data. ... MADS] Mahalanobis distance? Tags: LDA , MADS , Mahalanobis , Mahalanobis distance , multivariate , outliers , PCA . ... 6 Comments . ... Entries RSS . ... vlk on [MADS] Parallel Coordinates . ... Entries (RSS) and Comments (RSS) . ...

... In 1930, Trumpler noticed that linear diameters (LD) of open clusters increase with distance (D) from the Sun. ... Since that time, the interstellar absorption has become one of the best studied factor in astrophysics, and we may hope that current OCL distance scales are free from this LD-D correlation. To verify if this is the case we have chosen several modern OCL distance scales and test them with the same clusters and the same angular diameters that Trumpler had used back in 1930. ...

. Winds speeds on the platform. Polarized power from the panels. Rfi . Standing waves created by moving the tiedowns. standing waves can ruin observations but they are great tools for measuring distance (if you can generate an artificial src). Oscillations in the platform. previous first

... Home Education Classes AAA Winter Astronomy Class: Measuring Distances in Space тАУ Dec 2015 тАУ Feb 2016 . ... Classes . AAA Fall Astronomy Class: Astronomy Basics тАУ October-November 2015 . AAA Winter Astronomy Class: Measuring Distances in Space тАУ Dec 2015 тАУ Feb 2016 . AAA Spring Astronomy Class: The Physics of Astronomy тАУ February - March 2016 . ... This MonthтАЩs Sky тАУ April 2016 . ... Dec. ... Observing Resources for Amateur Astronomers - Part 1: Beginning Observers . ...

Hipparchus (and possibly Aristarchus before him) also derived the Moon's distance from the duration of a lunar eclipse . Because the Earth casts a much larger shadow than the Moon, such an eclipse usually darkens the entire Moon, for several hours. ... If the Sun is assumed to be very distant, and if the Moon crosses the middle of the shadow (if not, corrections must be made), the width of the shadow is expected to be about 2r , twice the Earth's radius r . ... Last updated 4 February 1999 Moon. ...

. Next: Diameters Up: Derived parameters Previous: Absolute magnitudes Contents . d_stars Compute distance D from parallax, absolute magnitude, or both. Christian Hummel 2015-04-28

. Next: Distribution in size of Up: The Interstellar medium Previous: Refractive scintillation . љ . Fresnel diffraction close to thin screen . Fraunhoffer diffraction far from thin screen . Fresnel distance - transition occurs . Jon Bell . Thu Dec 19 15:15:11 GMT 1996

... Ciel Espace, le magazine qui vous guide toujours plus loin . ... des actualitГїs . ... des interviews, des portraits . les plus belles images de l'Univers dГїcryptГїes pour vous . ... des pages consacrГїes Г la publication de vos photos Mais c'est aussi une vraie communautГї avec laquelle partager votre passion et nourrir votre curiositГї. Accueil Г? la une A quelle distance sont les Гїtoiles ? ... A quelle distance sont les Гїtoiles ? ... 23/05/2014 - Les cratГЕres de Mars sont-ils Г vendre ? ...

... In this paper we present the results of detailed B, V, R, I, and H study of the isolated nearby blue compact dwarf (BCD) galaxy NGC6789. Judging from the literature the observed galaxy has not been resolved into stars up to now. ... The distance of the galaxy, estimated from the tip of the red giant branch (TRGB) is 2.1 Mpc which places NGC6789 close to the Local Group. ... Key words: nearby galaxies: dwarf galaxies (NGC 6789): distance moduli: star content . ... Distance. ...

Kepler's Laws Kepler was an assistant to Tycho Brahe. Brahe had made extensive observations of the known planets and had accurately mapped the motion of these planets as they passed across the sky for a number of years. ... The orbits of the planets are ellipses with the sun at one of the foci. ... Look at the distance between the discs. ... Kepler's Laws All bodies sweep out equal areas in equal times If we look at the planets we have already seen that the planets change speed in their orbit. ...

... Bad Astronomy . Misconceptions . ... Bad Astronomy : "We're light years more advanced than our competition!" ... Even the closest astronomical object, the Moon, is 400,000 kilometers away! ... A beam of light will travel 9,500,000,000,000 kilometers in one year. This distance is defined as a light year ; the distance light travels in a year. ... This is another example of Bad Astronomy; like a light year, a parsec is a unit of distance, not time (to be specific, it equals 3.26 light years) . ...

... Tonight's Sky . ... The Magazine . ... Observing . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... space flight . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Imaging Basics . ... Observing Basics . ... Observing Basics: Distances in Space . ... Expand your observing at Astronomy.com . ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

The AstroGuide . ... AstroGuide | ... AstroGuide Listing . Login . See many more Astronomy Listings by: Category or Alphabet . ... Last Update July 27, 2006 . Listed Since July 15, 1998 . ... Web Site . http://janus.astro.umd.edu/astro/distance/ . ... Web . www.astronomy.net . ... Unless otherwise specified, web site content Copyright 1994-2016 John Huggins All Rights Reserved . dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . are trademarks of John Huggins ...