... Tonight's Sky . ... The Magazine . ... Observing . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... Bright planets meet at dusk . ... Astronomy magazine subscribers can read the full article for free. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

... Landsat 7 Views Planet Earth . ... Spiral disks are loose conglomerations of billions of stars and diffuse gas all gravitationally orbiting a galaxy center. ... Where did all the stars go? ... Here, a high concentration of dust and molecular gas absorb practically all the visible light emitted from background stars. Polar Ring Galaxy NGC 4650A . ... A rare type of galaxy known as a Polar Ring, NGC 4650A is composed of an old central group of stars and a young ring of stars rotating farther out. ...

Armagh, 2nd May 2002. Saturn and Mars are at the top left, Venus is the very bright object and Mercury appears through the clouds. ... All five planets visible to ancient astronomers can now be seen in alignment in the western sky. ... Next is Venus, the brightest planet or "Evening Star", followed by Mars, a much fainter red planet, then Saturn (near the red star Aldebaran, the brightest star in Taurus), and finally, slightly higher in the sky, the largest planet Jupiter. ...

Discover the cosmos! ... 2003 July 9 . HD70642: A Star with Similar Planets . ... Explanation: Astronomers have discovered a planetary system more similar to our own Solar System than any known previously . The bright star HD70642 , visible with binoculars toward the constellation of Puppis , was already known to be a star like our Sun. ... At only 90 light years distant , extremely faint early radio broadcasts from Earth are now passing this planetary system. ... About APOD | ...

Astronotes Armagh Planetarium's Stellar Blog! ... Planets . ... Monthly Sky Notes . ... October . ... By admin October 8, 2010 Posted in: Monthly Sky Notes . A giant from close up: an image made using data from the Cassini probe which flew past Jupiter in 2000. ... As it is so far from us, it takes JupiterтАЩs light a significant time to reach us тАУso when you see Jupiter tonight you are seeing it as it was 35€а minutes in the past. ... Posted October 12, 2010 at 11:15 PM . ... Astronotes . ...

3) Planets and Brown Dwarfs . ... By its nature, this method is most sensitive to massive planets orbiting close to their stars. ... That means that some of the more massive extrasolar planets could actually be brown dwarfs (although the statistics of the finds suggest that most of them are not). ... Another possible difference between brown dwarfs and massive planets is how they are born. ... They would base the fundamental definition on the mode of formation: a planet is built from planetesimals. ...

... Earth is the tiny spot between Jupiter and the Sun). ... Distance Radius Mass Name Orbits (000 km) (km) (kg) --------- ------- -------- ------- ------- Sun 697000 1.99e30 Jupiter Sun 778000 71492 1.90e27 Saturn Sun 1429000 60268 5.69e26 Uranus Sun 2870990 25559 8.69e25 * Neptune Sun 4504300 24764 1.02e26 * Earth Sun 149600 6378 5.98e24 Venus Sun 108200 6052 4.87e24 Mars Sun 227940 3398 6.42e23 Ganymede Jupiter 1070 2631 1.48e23 + Titan ... Extrema .. ...

. Mars is "behind" the sun from the earth's point of view and is therefore not visible in the nighttime sky (i.e. its up in the daytime). Venus it at greatest elongation and appears in the western sky as a bright object for 2-3 hours after sunset .

Saturn: The beauty of the rings. Saturn . ... Belongs to the giant planets . It has no definite solid surface. ... The free fall acceleration at the Saturn surface near equator is 9,06 m/s^2 . ... In the centre of the planet the temperature is about 20000K. The satellites . ... The rings of Saturn . ... It is proved that Saturn's rings (as well as the other planet's) are the fragments of the great cloud being near the planet with million kilometres length (see how the rings were formed ). ...

I was wondering what conditions should be met to have the "darkest" sky .. ... Upon the above publication of the Southern Galactic hemisphere, TunГ Tezel started seeking opportunities to create the Northern counterpart image. ... So, the initial quest of having the darkest possible sky have delivered us these two all-sky images of the two galactic hemispheres as seen from Planet Earth. Zoomable and 'full-screenable' fisheye view of the "darkest sky" Southern Galactic Hemisphere image. ...

... Search . ... Astrophysics Group . Research . ... Research and Instrumentation . ... While this seems an extraordinary endeavour, in light of what we have learnt about Solar System planets, only a handful of key ingredients are required to start characterising an exoplanet. ... The NGTS project is a partnership between the University of Cambridge, Queen?s University Belfast, University of Warwick, University of Leicester, Observatoire de Geneve, DLR (Berlin) and Universidad Catolica de Chile. ...

Now that well over 100 planets have been discovered, we no longer need to ask the question "Are there planets out there?" ... The objective of XO is to find additional hot-Jupiters (like HD 209458b) that transit stars bright enough for detailed follow-up studies to be done with existing telescopes such as HST, Keck, and the VLT. ... Transit observations by themselves provide no information about the mass of the planet and radial velocity studies can yield only minimum masses. ...

... Bad Astronomy . ... Bitesize Astronomy . ... Bad Astro Store . ... Slacker Astronomy . ... Keep Bad Astronomy close to your heart, and help make me filthy rich. ... Life Under the Moon . ... Seeing Jupiter's Moons . ... Time Zones and the Spherical Earth . A Companion to the Earth? ... December 19, 1999) . ... Big Moon, Little Moon . ... How Big is the Moon? ... 14, 2000) . ... 2008 Phil Plait. ... Subscribe to the Bad Astronomy Newsletter! Talk about Bad Astronomy on the BA Bulletin Board! ...

Finding Himalia, The Fifth Brightest Moon Of Jupiter . Articles | ... Himalia is the only moon other than the Galilean moons of Jupiter that is visible in an amateur size telescope. ... I normally use “The Sky” from Software Bisque for planning my observing sessions and in helping me find objects, but it only has the Galilean moons for Jupiter so I used Red Shift (version 3 at the time) which I also had on my computer. ... www.astronomy.net . ... dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

New Moons of Uranus . Brent Gladman's Home Page . ... The discovery of two probable distant satellites of Uranus was reported by B. Gladman, P. Nicholson, J. Burns and J. Kavelaars. ... This discovery was reported in the IAU Circular 6764 . ... Discovery image of S/1997 U 2 . This shows the discovery image of brighter of the two new moons of Uranus. ... This shows the discovery image of faint new moons of Uranus. ... This shows another discovery image of faint new moons of Uranus. ... Uranus . ...

ARCSAT ID NUMBER: AS01 DESCRIPTIVE TITLE: Search for Short-Period Planets Orbiting Bright White Dwarfs PI: Brett Morris (UW) OBSERVER(S): Brett Morris (UW), Doug Branton (UW) UNCERTIFIED/UNTRAINED OBSERVERS: Undetermined Pre-MAP students ... In addition, since typical white dwarfs are roughly Earth-sized, the transit of an Earth-sized planet can cause changes in brightness on the order of several tens of percent for durations on the order of one minute (Agol 2011). ...

... An Automated Search for Extrasolar Planet Transits M. G. Hidas, J. K. Webb, M. C. B. Ashley, C. H. Lineweaver University of New South Wales, Sydney 2052 NSW, Australia J. Anderson University of California, Berkeley, USA arXiv:astro-ph/0209388 v1 19 Sep 2002 M. Irwin Institute of Astronomy, Cambridge, UK Abstract. We are setting up a new search for transiting extra-solar planets using the 0.5m Automated Patrol Telescop e at Siding Spring Observatory, Australia. ... 2002; Mayor et al. 2002). ...

... This glossary is not meant to be an exhaustive list of techno-definitions. ... Is there a term you don't see here? ... Do you know how to pronounce the CONSTELLATIONS , STARS , or the PLANETS and their MOONS ? ... First Law - the orbit of each planet is an ellipse with the sun at a focus . ... LIGHT BUCKET: A common slang term for a large apertures . ... LIGHT POLLUTION: The illumination of the night sky caused by artificial light sources on the ground (streetlights, billboards, etc.) ...

Microsymposium 38, MS083, 2003 (A4 format) MERCURY: LOCAL VARIATIONS OF THE PHOTOMETRIC RELIEF. ... Because of trajectory and pointing angle constraints the planet could be observed from Mariner 10 only over a small range of phase angles between about 75o and 110o. Therefore the photometric investigations are restricted to measuring the distribution of brightness on the Mercurian disk. ... Raw versions of real-time processing pictures FDS 0000984 and FDS 0000986 were used (images 196 and 202). ...

... Magnetic Storms . ... Cosmic Rays . ... Energetic Particles . ... Solar fast Particles . We cannot observe the way the distant universe accelerates cosmic rays or produces energetic photons, but acceleration processes also occur on our Sun , though on a much more moderate scale. ... That is why such events are often missed by cosmic ray detectors near the equator, where the lowest energies are excluded by the Earth's magnetic field. ... Should we be concerned about solar energetic radiation? ...