... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

... HST . What is the offset in the U2 direction that can be taken before a gap appears? ... HST Peer Review Process . ... HST Overview . Overview . ... Retrieving HST Data . ... HST Science Year in Review . ... What is the offset in the U2 direction that can be taken before a gap appears in the coverage of the sky between the two pointings? ... Same question for a U3 offset. ... This should allow you to accurately address the issue of optimal offsets in the mosaic. ...

Next: Sky background definition Up: Background Definition Previous: Smoothing spline interpolation . The command BACKGROUND/SMOOTH enables to define the background without previous order definition. This feature is useful for example to correct for the background the image required for the order definition. ... All above methods are implemented in command BACKGROUND/ECHELLE and selected by the echelle keyword BKGMTD . ...

... Primordial theory review : Dick Bond . Defects and the CMB review : Andy Albrecht . ... Gravitational wave contribution to CMB anisotropies : V.B. Lukash and E.V. Mikheeva . C_l from cosmic strings : Lloyd Knox . Some aspects of CMB anisotropies induced from topological defects : Mairi Sakellariadou . ... CMB anisotropies from scaling sources : Ruth Durrer . ... SZ observations I : Sarah Church . ... Holes in the microwave sky? ... Detecting cosmic strings in the CMB : James Robinson . ...

... SGML . The text/html content type . In this section, we begin the specification of HTML 4.0, starting with the contract between authors, documents, users, and user agents. ... These recommendations are not normative and conformance with this specification does not depend on their realization. ... An HTML document is an SGML document that meets the constraints of this specification. ... A user is a person who interacts with a user agent to view, hear, or otherwise use a rendered HTML document. ...

... self-absorption - the absorption of light shining on an object by a process similar to that which produced the light originally; if a cloud emits less light than it absorbs from other clouds behind it, this net loss of light, termed self-absorption , causes the foreground cloud to appear darker than the background field (the term is from spectroscopy, where small absorption dips sometimes occur in larger emission lines, making the latter look as if it is absorbing part of itself) . ... HISA Main ...

... March 8, 1999 . A Jupiter-Venus Conjunction . ... Explanation: Venus and Jupiter appeared unusually close together in the sky last month. The conjunction was easily visible to the unaided eye because Venus appears brighter than any background star. The two planets were not significantly closer in space - Venus just passed nearly in front of Jupiter as seen from the Earth . ... Perhaps the hardest to see is Mercury , visible below Venus but above the foreground Earth . ... About APOD > . ...

Astronomy Picture of the Day . A Jupiter Venus Conjunction . ... 8.03.1999 . ... The conjunction was easily visible to the unaided eye because Venus appears brighter than any background star. The two planets were not significantly closer in space - Venus just passed nearly in front of Jupiter as seen from the Earth . ... U. Based on Astronomy Picture Of the Day . Publications with keywords: Jupiter - Venus - conjunction . Publications with words: Jupiter - Venus - conjunction . ...

... There has been a heated public discussion in the past few years about whether our ninth planet is really deserving of the name. Since Pluto orbits a star, and is much less luminous, it certainly satisfies the definition we have above. The problem is actually not with Pluto, but with a very large number of other bodies in our Solar System which also satisfy this definition, but which are not called planets. Perhaps the most notable of these is Ceres, the largest asteroid. ... Planet . ...

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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 . ...

... Judged by their instrumental profiles, spectrometers fall into two basic classes---Lorentzian and Gaussian---with many other line profile functions (sinc functions, Voigt functions, Airy functions, etc.) falling into one of these two categories in some limit. We demonstrate that the Rayleigh, Sparrow, and Houston resolution criteria are of limited use compared to the ``equivalent width'' of the line profile. ... Rayleigh criterion. ... All of these functions have continuous higher derivatives. ...

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... Though Flint knows the interface definitions (i.e. number, type and intent of each argument) of standard FORTRAN functions, it is desirable for users to build and use a file (or files) describing the interfaces to their own library. ... The format is: flint -o file .. ... While these interface definitions could be input along with normal source files, preceding the interface file with the -l (library) switch has the advantage that the source of this file does not appear in the listing file. ...

An image of the grand design of spiral galaxy M100 obtained with NASA's Hubble Space Telescope resolves individual stars within the majestic spiral arms. ... Hubble has the ability to resolve individual stars in other galaxies and measure accurately the light from very faint stars. This makes space telescope invaluable for identifying a rare class of pulsating stars, called Cepheid Variable stars embedded within M100's spiral arms. ... 617) 495-7062 . Fax: (617) 495-7356 . ...

... The aim of this workshop is to get together theorists, who develop models leading to such cosmic polarization rotation (CPR), and experimentalists, who search for CPR using a variety of complementary methods, in order to discuss current results and future directions. The workshop will take place at the Villa Il Gioiello on the Arcetri hill near Florence, where Galileo, the first scientists to test the equivalence principle, spent the last 10 years of his life. ... Home . ... cpr@arcetri.astro.it . ...

spaceweb@oulu.fi - last update: 1 July 1998, 1200 UT (RR) . ... Relates the wave number k to the wave frequency. ... From the equation of motion , m d v /dt = q( v x B ) one can calculate that, in a presence of magnetic field B , a charged particle is accelerated in direction perpendicular to both v (perp) and B . ... The angle a between magnetic field B and velocity vector of a charged particle, v ., i.e., sin a = v(perp) / v(total), where v(perp) refers to the velocity component perpendicular to B . ...

Blackholes2 Forum Message . Forums: . ... Brilliant! Thanks . ... My interpretation of the MM experiment was that it did not prove the speed of light was constant in all directions because it could not see direction. ... People assume that the space containing the experiment is rigid (or 4-D grid space-time with fixed scale. ... www.astronomy.net . ... Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

... Temp_2-10.)/100. ,0.9); # declare Cblu_2 = min( Temp_2 /30. , 1.0 ); #end # declare Color_1 = Cred_1, Cgrn_1, Cblu_1 ; # declare Color_2 = Cred_2, Cgrn_2, Cblu_2 ; # declare Spot_1 = Cred_1-0.1, Cgrn_1-0.1, Cblu_1-0.1 ; /* Ultimately need to define the surface of each star - in close binaries ... Roche equipotential */ /* Primary star (with spots) */ union { sphere { 0,1 texture { bozo scale 0.3 turbulence 0.9 texture_map { [ 0.0 ...

Each Apache configuration directive is described using a common format that looks like this: . ... This indicates the format of the directive as it would appear in a configuration file. This syntax is extremely directive-specific, and is described in detail in the directive's definition. ... If the directive has a default value ( i.e. , if you omit it from your configuration entirely, the Apache Web server will behave as though you set it to a particular value), it is described here. ...