Next: Estimating the angle Up: Wavelength Calibration Previous: General Description . The wavelength calibration involves a physical equation, the echelle relation and regression analysis to achieve estimates of the dispersion relation. Provided that the echelle dispersion is performed with a grating, any echelle spectrum can be calibrated usually with four lines used as pre-identifications and a catalog of laboratory wavelengths associated to the calibration lamp. ... Echelle Relation) . ...

Hide Zen home . ... Index . ... Do we really need them for database indexing ? ... We need simple numbering scheme, so that for any given point we could easily calculate the number of "pixel", this is what HealPix provides and lacks HTM. ... During Rtree queries the number of index blocks read is several times greater than during Q3C queries. ... But in Q3C scheme, as we showed before, the circle is segmented, so we extract from the database only a few percents more data than occur in the circle. ...

... Bad Astronomy . ... Bad Astronomy : The Moon appears larger on the horizon than overhead because you are comparing it to foreground objects. Good astronomy : The Moon does appear larger on the horizon, but it is because of the way we perceive the sky. ... The most common misconception is that it is because you are unconsciously comparing the Moon to foreground objects like trees and houses, or even the horizon itself, and that makes the Moon look bigger than when it is all alone in the sky. ...

Click here for links to download all of "The Exploration of the Earth's Magnetosphere " in a variety of compressed formats. ... A basic chronology of key dates in the exploration of the magnetosphere. ... The Answer Man (#1) Questions from users and answers. The Answer Man (#2) More questions and answers. Parts are internally linked) . References, links and resources about the magnetosphere (not updated). Exploration" home page .. ... Official GSFC Home Page .. NASA WWW Home Page . ...

... Natalya V. Raguzova and Sergei B. Popov . ... We present a compilative catalogue of Be/X-ray binaries and candidates in the Galaxy and in the Large and Small Magellanic Clouds. This catalogue contains 160 sources and provides information on names and spectral types of optical components, distances, on spin characteristics of neutron stars, and on orbital and X-ray properties of binary systems. ... Be/X-Ray Binaries and candidates in the Galaxy . Galactic sources: comments to the Table 1 . ...

Free Space Optical Communication Systems . ... Airplane - geostationary satellite laser communication. ... Air ( space) optical communication systems ( AO ) . ... The Optical ground station was constructed at Teide observatory, Tenerife, Canary Islands for laser communication experiments from ground to geostationary (GEO) satellites. ... Laser communication experiments between ARTEMIS satellite and optical ground station (OGS) ESA at Canary Islands are performing also. ... CW laser test experiments . ...

Photon Scattering: Basic Principle of Photon Scattering . Audio Narration is available . No Scattering: Photon Source and Detector . ... For optical photons, scattering goes as wavelength to the -4 power. In the case of blue photons compared to red photons, this means that blue photons are about 10 times more likely to get scattered than red photons. ... Watch the blue photons scatter away from the detector . ... Interstellar dust make stars appear redder than they really are . ...

Title : MAKEITSO.WAD Version # If Any : 1.0 Date Finished : 5.Jan.96 Author : Marcus Malden Email Address : rp11910@online-club.de marcus.malden@uni-essen.de http : http://online-club.de/m3/rp11910 Other Files By Author : See MALWAD.TXT for a complete description of my PWAD-Levels compared to its filedate. ... Title : NORBERT.WAD Version # If Any : 1.0 Date Finished : 31.DEC.95 Author : Marcus Malden Difficulty Settings : Yes Base : New levels from scratch Build Time : 48 min. ...

... Starburst Galaxy Messier 94 . ... Beautiful island universe Messier 94 lies a mere 15 million light-years distant in the northern constellation of the hunting dogs, Canes Venatici. A popular target for earth-based astronomers, the face-on spiral galaxy is about 30,000 light-years across, with spiral arms sweeping through the outskirts of its broad disk. ... Bright Spiral Galaxy M81 . ... The grand spiral galaxy can be found toward the northern constellation of the Great Bear (Ursa Major). ...

... Launch Date: 1966-08-10 . ... The Lunar Orbiter 1 spacecraft was designed primarily to photograph smooth areas of the lunar surface for selection and verification of safe landing sites for the Surveyor and Apollo missions. ... The spacecraft was placed in a cislunar trajectory and injected into an elliptical lunar orbit for data acquisition. ... An 80-millimeter lens system was used to obtain Medium-Resolution (MR) photos, and a 610-millimeter lens system was used for High-Resolution (HR) photos. ...

To the IUM main page . Our Web site is written for the most part in Russian. ... Those who cannot read Russian are referred to the English version of our page, but they should be warned that nothing but general information on IUM is to be found there. ... The rest of this text is for those who can read Russian but cannot make their Web browser show Cyrillic letters to them. An immense part of our Web page is lists of titles of courses read (or being read) at the Independent University. ...

Optical Observatories . ... National Optical Astronomy Observatories . ... Adam Mickiewicz University - Astronomical Observatory . ... Astronomical Institute and National Observatory of Athens . ... Jagiellonian University Astronomical Observatory - Scientific research here comprises radio and extragalactic astronomy, solar radio emission, active galactic nuclei, interstellar matter, galaxies, cosmology, variable stars and comets. ... National Radio Astronomy Observatory Home Page . ...

... Observing . ... Solar Observing . ... April 3 (SUN) - Solar Observing, Central Park , Manhattan . ... APRIL'S SKY . ... Lecture Series at the American Museum of Natural History The Amateur Astronomers Association is proud to present an astronomy lecture series from October through May each year for our members and the .. ... The€аAmateur Astronomers Association of New York€аwas organized in 1927 to promote the study of Astronomy, emphasizing its cultural and inspirational value. ...

RSSI is interconnected with : . NASA Integrated Services Network (NISN) , via 512 Kbps link. NASA Internet provides connectivity to global Internet for RSSI users. Leading Russian science networks via Moscow Fiberoptic Backbone: . ... MSU-Net provided by Moscow State University . RUNNet provided by Moscow State University . Radio-MSU provided by Skobeltsyn Institute of Nuclear Physics Moscow State University . ... Primary Russian ISPs via M9 interconnect exchange in Moscow: . ...

... Main mirror assembly consists of: . mirror cell structure . ... relief mechanisms . ... central bed Main mirror is fixed in the mirror cell in axial direction by three rigid supports. ... The butt relief of main mirror is implemented according to Lassel and involves 18 relief mechanisms, three of which are replaced by rigid fixing supports after the adjustment. The side relief is similar with the relief mechanisms working in both directions since mounting points are glued to the mirror. ...

... Armagh Goes Digital . ... Hotels . ... This four star hotel provides the largest hotel conference facility in Northern Ireland. The hotel overlooks the County Armagh Golf Club and the picturesque grounds of a 13th century Franciscan friary. Tel: +44 (0) 28 3751 8888 . ... Family-run hotel located in the Armagh City Centre, close to all the tourist amenities. Tel: 028 3752 2028 . ... Saint Patrick's Cathedral (Church of Ireland) . ... Tel: 028 3752 3142 . ... Tel: 028 3752 2802 . ...

NMW survey overview . Access image archive . ... The New Milky Way survey aims to detect bright (V<13.5) optical transients near the Galactic plane using an automated wide-field (8x6 deg.) system capable of surveying the whole Milky Way area visible from the observing site in one night. ... All images obtained during the transient search survey are available online (please use the image archive access form ). ... Images per field: . ... Images per night: . ... Milky Way imaging time: . ...

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... Tonight's Sky . ... The Magazine . News . Observing . ... Advertiser Links . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Open cluster NGC 2818, spiral galaxy NGC 2964, and spiral galaxy NGC 2976 . ... Astronomy for Kids . ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ... Astronomy Magazine . ...

... The European HST Archive has been moved to ESA's European Space Astronomy Centre ( ESAC ), Spain, where most of ESA's Space Science Archives are located and operated from. ... The Space Telescope European Coordinating Facility (ST-ECF), jointly operated by ESA and the European Southern Observatory ( ESO ) was, until the end of 2010, the European HST science facility, supporting the European astronomy community in exploiting the research opportunities provided by the Hubble Space Telescope. ...