... Here, $\lambda = {-180^{\circ}} \ldots {+180^{\circ}}$ is the longitude and $\varphi = {-90^{\circ}} \ldots {+90^{\circ}}$ the latitude in the original coordinate system. ... begin{equation*} \tan(l_{0} - l) = \frac{\cos(\delta) \sin(\alpha - \alpha_{0})}{\sin(\delta) \cos(\delta_{0}) - \cos(\delta) \sin(\delta_{0}) \cos(\alpha - \alpha_{0})} \end{equation*} . ... begin{equation*} \sin(b) = \sin(\delta) \sin(\delta_{0}) + \cos(\delta) \cos(\delta_{0}) \cos(\alpha - \alpha_{0}) \end{equation*} . ...

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• PRECDATE

... We can help students grasp the significance of Hubble's extremely keen eye, and learn a bit about angles and math in the process, with the following in-class activity. ... Looking through binoculars or telescopes allows us to magnify a small section of the sky. To measure sizes or distances in that small section, astronomers divide a degree into 60 smaller pieces called arcminutes, and further subdivide minutes into 60 smaller sections called arcseconds. ... 30 feet = . ... 36 seconds . ...

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... sin f = y / r . cos f = x / r . ... They are now viewed as new definitions of the sine and cosine, for the polar angle f given by x and y ( a slightly different way of formulating this definition is described further below ). ... sin 2 f + cos 2 f = 1 . ... Angle . ... Many trigonometry texts define the sine and cosine slightly differently, using the so-called unit circle . ... Then the distance AB ("the sine line") equals sin a , and the distance OA ("the cosine line") equals cos a . ...

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... In polar coordinates, the point P is defined by its distance r from the origin O (see drawing) and by its polar angle ("azimuth" on a map) between the x-axis and the "radius" r = OA, measured counter-clockwise. ... When one or both are negative , the angle f is larger than 90 degrees, and such angles never appears in any right-angled triangle. ... There is a simple solution , though: use the above equations to re-define sin f and cos f for such larger angles! ... But it also works for larger angles....

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... Abstract This routine computes the Jacobian of the transformation from spherical to rectangular coordinates. ... dx/dr dx/dcolat dx/dlon | ... Given a state in spherical coordinates ( r, colat, lon, dr, dcolat, dlon ) the velocity in rectangular coordinates is given by the matrix equation: t | ... Determine the Jacobian of the transformation from cylindrical to rectangular at the coordinates at the given cylindrical coordinates at time t./ drdsph_c ( r(t), colat(t), lon(t), jacobi ); /. ...

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• CSPICE Routines: SPHREC_C
• CSPICE Routines: DRDLAT_C
• CSPICE Routines: SPHLAT_C

Next: *wcscoord* all Up: Celestial Coordinates from Image Previous: *tvlabel, xexamine* . ... Type pixel coords in skypix . xr xspatial xs skypix .oformat = ``hours'' # to reset the default which is ``degrees''. xs skypix input coordinate system ( J2000 ): xdata$rh110267_img # the image file name output coordinate system ( J2000 ): image # to use coord conversion # in image file header or B1950 or J2000 # epoch of output can be specified input file list (STDIN): cr ...

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• zhtools
• *wcscoord* -- all purpose coordinate conversion
• Spatial Region Coordinates

The azimuth encoder rack gear is mounted on the inside of the azimuth ring girder. The azimuth encoder turns on this gear as the azimuth moves 0 to 720 degrees. ... The software assumes that this arc length along the encoder rack gear is correct (at a constant radius of 127/2 feet). The error in the radius of the rack gear becomes an azimuth error. To measure the error in the azimuth encoder rack gear, jon hagen built a proximity sensor. ... To compute the az encoder runout error: . ...

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... SqDegToSterad . ... Square degrees to steradian . ... SqDegToSterad /3600.0 . Square arcminutes to steradians . ... Square arcseconds to steradian . SteradToSqDeg . ... Steradian to square degrees . ... SteradToSqDeg *3600.0 . Steradian to square arcminutes . ... Steradian to square arcseconds . ...

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• Angle conversion factors

lsst.coordConv љ unknown . ... Classes . ... All љ Classes љ Namespaces љ Files љ Functions љ Variables љ Typedefs љ Enumerations љ Enumerator љ Pages . coordConv: Astronomical Coordinate Conversions . The coordConv package provides the following classes and functions. ... Coord : represents a position on the sky, with proper motion and radial velocity; provides easy access to spherical and cartesian position. ... Position conversion functions: . ... Time conversion functions: . ...

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• lsst.coordConv: coordConv::Coord Class Reference
• Rotation range
• lsst.coordConv: coordConv::PVTCoord Class Reference

... Contents . ... Sidereal time . ... Mean longitude of the Moon, mean elements of the Moon's orbit and equator . ... Ephemeris for physical observations of the Sun . ... Ephemeris for physical observations of the Moon . ... Matrix elements for conversion to CIRS . ... Conversion of mean time to sidereal time (with accuracy 0.01 s ) . ... Conversion of sidereal time to mean time (with accuracy 0.01 s ) . ... Conversion of mean time to sidereal time (with accuracy 0.001 s and 0.0001 s ) . ...

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• AY2014 (contents)
• AY2012 (contents)
• AY2015 (contents)

From Herschel's catalog, the first accurate stellar parallax measurement of 0.32 seconds of arc for the star 61 Cygni was published by the F.W. Bessel in 1838. ... 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. ... An Orbit in Curved Space This is a prediction made by General Relativity and confirmed by direct observation of Mercury. ...

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... Tonight's Sky . тАФ . ... RISE тАФ . ... Observing . ... Star Atlas . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... What exactly is a degree in terms of the distance between stars? ... A measurement in degrees has nothing to do with the true distances between celestial objects. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ...

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• How do astronomers determine the ages of stars? | Astronomy.com
• First direct distance to Andromeda | Astronomy.com
• What determines the length of totality during a solar eclipse? | Astronomy.com

Aristarch is Copernic of Classic World. ... First Aristarch determined the fact for how many times the Sun was father then the Moon and then he compared the Sun and the Moon with the Earth. ... Only the Moon rotates around the Earth. ... Gipparch suggested that the Sun turned around the Earth steady and in circumference but the Earth is displaced according its centre. ... The orbit point in which the Sun is nearer to the Earth Gipparch called perigee and the most remote one he called apogee . ...

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. Distance Conversion Calculator . by Matt Oltersdorf 2000 04 02 2225 UTC . Type the known value into the appropriate units field, click the . calculate button and the program will show all values for . related unit properties. Kilometers . Meters . mm . Inches . Feet . Yards . Miles . Astronomical Units (A.U.) . Light Year (LY) . Parsec (pc) . Kilometers . Miles .

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... The described algorithm is suitable for measurements of complex images of stars. ... a) the zero-based number of stars in the complex (multicentric) image, . b) set of preliminary coordinates - x i , y i , for all stars, index i is number of a star, . ... i - index of a star in the complex image; . ... These parameters are calculated by a nonlinear method of a least squares.The main output parameters of this algorithm are x i , y i ; where the index i is number of a star in the multicentric image. ...

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... Returns UT1 in seconds, with UTC input in seconds. ut12gst ( utc _real [, ut1 _real ]) Function. Returns GST in hours, inputs are in seconds. hourangle ( gst _real , ra _real ) Function. Return hourangle in hours, with inputs also in hours. zenithangle ( ha _real , dec _real ) Function. Return zenithangle in degrees with inputs ha in hours and dec in degrees. mirrorangle ( ha _real , dec _real ) Function. ... Return horizon coordinates for input azimuth and elevation angle in degrees. ...

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• POLIMODEL (V2.00) --- November00 --- POLIMODEL (V2.00)
• VST image of the star-forming region Messier 17 | ESO
• POLIMPLOT (V2.00) --- November00 --- POLIMPLOT (V2.00)

... After all we cannot send a probe to the star Altair to confirm that it is 17 light years away. ... The "Bessel determined that the star 61 Cygni was about ten light years away" Earth goes around the Sun in one year, so in six month it is in the opposite position in its orbit. ... In 1838 Bessel determined that the star 61 Cygni had a parallax of 0.314 arcseconds and therefore the star was about ten light years away (today the distance is more precisely measured to be 11.4 light years). ...

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... SQL | ... Tutorial: determine H0 using SQL queries to LEDA . ... We select in the database all galaxies with known velocity and magnitude and similar to a given template for which we know the distance, the magnitude and the radial velocity. ... We simply have to choose a property which does not depend on the distance, as for example the rotation velocity ( log(vrot) ) and select the galaxies having log(vrot) in a very narrow range around the value for the template galaxy. ... leda@univ-lyon1.fr ...

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• WCS(3)
• Column label: OBSE
• What was measured?

... Cooling and thermal control system (CTCS):an angle between normal of thermal radiator plane (Z-axis) and vector "SC-Sun" must exceed 90 deg.. ... The axes of the first two sensors are in the plane YOZ; they have an angle of 35 degrees with Y and -Y axis being inclined to the direction of -Z axis. ... 30 degrees for Sun; . ... An angle between +Z-axis and direction to the Sun center must exceed 90 degrees. ... An angle between direction "SA-Sun(center)" and XOZ plane must not exceed 30 degrees. ...

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• Description of the RadioAstron project, english version

... This paper describes IRSA's new generation query support in which the Informix server has domain-specific embedded query support, e.g., datablades modules with astronomical functionality. The first IRSA Astronomical datablade developed supports coordinate conversions. ... Coordinate conversion is a complicated process. ... The embedded astronomical query which combines a data searching engine with coordinate conversion capability is an efficient tool for the astronomical community. ...

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• Representations of Celestial Coordinates in FITS
• How to Piece Together Diffracted Grating Arms for AXAF Flight Data
• Modeling Scattered Light in the HST Faint Object Spectrograph