The Discovery of the Galilean Satellites . ... Probably the most significent contribution that Galileo Galilei made to science was the discovery of the four satellites around Jupiter that are now named in his honor. Galileo first observed the moons of Jupiter on January 7, 1610 through a homemade telescope. He originally thought he saw three stars near Jupiter, strung out in a line through the planet. ... Galileo's Observations of Jupiter's Moons . ... Jupiter . ...

Supernova 2009js in NGC 918 . This page is devoted to information on Supernova 2009js in NGC 918 . Basic information on this SN, including the last reported brightness, on this Supernova can be found on the main page . Information on the original web pages for many of these images can be found on the updates and links web pages. Discovered independently by Lick Observatory Supernova Search (USA) and Koichi Itagaki (Japan). ... 2009/10/11.44 . 17.2 . ... Joseph Brimacombe . ...

... Tonight's Sky . ... Observing . ... Sky this Month . ... Astronomy for Kids . ... Can you explain Mercury's retrograde motion? Do other planets appear to do this also? ... When astronomers talk about retrograde motion, generally they refer to the apparent motion outer planets make as Earth passes them while orbiting the Sun. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2014 October 15 . Mysterious Changing feature on Titan . Image Credit: Cassini Radar Mapper , Cornell , JPL , ESA , NASA . Explanation: What is that changing object in a cold hydrocarbon sea of Titan? ... Subsequent observations in 2014 found the object remained -- but had changed! ... About APOD | ... A service of: ASD at NASA / GSFC . ...

... In 1610, Galileo turned his telescope to the heavens and discovered that the planet Jupiter had four bright moons. ... Jupiter's Rings . ... Unlike Saturn's bright rings which are composed of chunks of rock and ice, Jupiter's rings appear to consist of fine particles of dust. ... Exploring Saturn's Rings . ... Saturn's spectacular system of bright rings has been the subject of study and wonder since Galileo first turned his telescope on the ringed planet in 1610. ... M57: The Ring Nebula . ...

home publications > mercury . ... Astronomy Beat . ... Nearly four centuries ago, Galileo's simple observations of Earth's planetary sibling, Venus, buoyed the proponents of a Copernican universe. ... The Italian astronomer had settled into a new house in Florence and had begun to observe Venus, which in November 1610 would have appeared as an evening star, bright in the western sky after dusk. ... From these two observations, Galileo inferred that Venus must orbit closer to the Sun than does Earth. ...

A team of U.S. and German astrophysicists have made the first ever detection of X-rays coming from a comet. ... Following the initial detection, the team reported repeated X-ray emissions from the comet over the next 24 hours. ... One preliminary theory is that X-ray emission from the Sun was absorbed by a cloud of gaseous water molecules surrounding the nucleus of the comet, and then were re-emitted by the molecules in a process physicists call "fluorescence." ... Comets . ...

... Any water on Mars is locked up in the ice caps. ... The most recent successful mission to Mars is the Mars Science Laboratory better known as the Curiosity rover. ... CuriosityтАЩs primary role is to search for conditions that may have once been able to harbour any sort of bacterial life concealed beneath the Martian surface. ... Using what we know about life on Earth, where there is water, there is life, signs of water may help us understand what Mars was like billions of years ago. €а . ...

ASTRONOMY . ASTRONOMY is a science, which studies solids and occurrences in the sky. ... They built the picture of the world according to their knowledge. With the course of time the world picture was being changed because there appeared new facts and information and new theories on the celestial occurrences and what is more impotant there appeared an opportunity to check up the correctness of ideas through the observation and measuring using the new achievements of the sciences. ...

... Changed time to 08:00-14:00 (AT, HO, MP, SH, HH) V125a Nov 01 Cancel 3C380 (VLBA, GO) VS07u Nov 03 Changed observing times (KA, HO, HH) V053c3 Nov 05 Changed observing times (VLBA) VS09q Nov 20 Cancel (GB, AR) V019b Nov 25 Changed observing times (AT, HH, MP, UD) V001a Dec 02 Removed AT VS03j Dec 03 Cancel (KA, MP, UD) V029a Dec 10 Changed times (MK, TI, AT, HH, MP) V035a1 Dec 21 Changed stop time (VLBA, GO, RO) Modified on Sep 26: Most changes are related to VSOP survey source additions. ...

M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Color CCD Picture Very Deep M57 Image . ... M81 image More About M81 M81 Supernova Ultraviolet Image of M81 More about Ultraviolet Imaging . M82 image More About M82 M82 False Color M82 True Color . ...

Image credit: Michael Nolan, Arecibo Observatory. These radar images of near-Earth asteroid 2001 SN263 were obtained on 2008 Feb 12 and 13. ... Image from Feb 12 . ... First near-Earth triple asteroid discovered by Arecibo Observatory . ... was discovered this week by astronomers at the sensitive radar telescope at Cornell University?s Arecibo Observatory in Puerto Rico. ... For example, Arecibo has discovered more than half of the near-Earth binary asteroid systems discovered since 1999. ...

... To be read in conjunction with Section 4.11 of the WFPC2 Instrument Handbook , -Version 4.0. ... 1 The second study found evidence that CTE loss for faint stars has increased with time (Whitmore, 1998). The primary observational consequence of CTE loss is that a point source at the top of the chip appears to be fainter than if observed at the bottom of the chip, due to the loss of electrons as the star is read out down the chip (see Figure 1 ). ... Last updated: 06/16/98 10:38:00 . ...

... This will be similar to otherб IAA events, except that there will be an optional supper first at the LNDC cafe - see details below. ... Neptune soon joined the planet club while Pluto had a brief membership during the 20th century. б б б  Astronomers have found though that the outer solar system is a far more dynamic place than was originally thought with various classes of asteroid-sized bodies now catalogued, while Pluto itself is just one of a collection of similar sized objects. ...

... Science Users Information > Observing Facilities > La Silla Facilities > La Silla Science Operations . ... La Silla News . ... Internal Pages . La Silla Science Operations Department (LSO) is part of the La Silla Paranal Observatory and is in charge of the operations of the telescopes on La Silla. ... In the La Silla Science Operation pages, you should find all the information you need for your observations from the time you have an idea of observations until when you finish processing your data. ...

XMM­Newton CCF Release Note XMM­CCF­REL­32 EPIC Bad Pixels D Lumb October 31, 2000 1 CCF components Name of CCF VALDATE List of Blocks changed CAL VERSION XSCS flag EMOS1 BADPIX 0007 1999­01­01T00:00:00 BADPIX YES EMOS2 BADPIX 0007 1999­01­01T00:00:00 BADPIX YES 2 Changes It was discovered that for early operations, an incorrect set of up­linked bad pixel tables was used on­board. ... 5 Expected Updates Whenever there is a new release of badpixels for on­board the CCF file will be updated. ...

Next: Scattering properties Up: Polarization properties (transmitted radiation) Previous: Linear polarization: wavelength dependence . Traditionally, the main problem considered in connection with circular interstellar polarization is the meaning of the wavelength where changes the sign . ... This is also demonstrated by Fig. 19 (lower panel) which shows the wavelength dependence of the factors of linear and circular polarization for particles of magnetite as was done by Shapiro ([ 1975 ]). ...

To change your password: passwd Old password: enter your current password New password: enter your new password Retype new password: re-enter your new password . Enter the command passwd and then respond to the prompts by entering your old password followed by your new one. ... The passwords will not appear on the screen as you type, to prevent other people from seeing them. If you make a mistake, the message Mismatch - password unchanged. is displayed and your password remains unchanged. ...

... 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. ...

Follow-up astrometry and recoveries are made with the ANU 40 inch (1.0-m) f/8 reflector at Siding Spring Observatory (IAU code 413). ... A routine follow-up of 2003 WY153 on 2003 Dec 15 became much more than routine when a faint object with unusual motion vector was found close to the target asteroid. ... During routine astrometry with the 1.0-m to improve the orbit of the Apollo asteroid 2004 CB, the asteroid was found on March 30 to have a short tail! ... Siding Spring Survey Main Page . ...