... Dione's icy surface includes heavily cratered terrain, moderately cratered plains, lightly cratered plains, and whispy material. The heavily cratered terrain has numerous craters greater than 100 kilometers in diameter. ... Much of the heavily cratered terrain is located on the trailing hemisphere , with the less cratered plains area existing on the leading hemisphere . ... Because Dione is relatively small, an impact causing a 35 kilometer (21 mile) crater could have spun the satellite. ...

Understanding Europa's Radiation Environment and How it Influences Landing Site Characterization G.W. Patterson, L.M. Prockter, C. Paranicas Applied Physics Laboratory Introduction · The surface of Europa is weathered by charged and neutral particles, micrometeroids, and photons. ... Background · Criteria for characterizing potential landing sites [e.g., Figueredo et al., ... 2004) Background · Criteria for characterizing potential landing sites [e.g., Figueredo et al., ... Figueredo et al., ...

... Impact craters and associated concentric rings are about the only features to be found on Callisto. ... It has a bright central region that is 600 kilometers in diameter, and its rings extend to 3000 kilometers in diameter. ... This image shows the heavily cratered surface of Callisto. ... Also visible is a fresh, sharp-rimmed crater some 90 km (56 miles) across named Igaluk (center left third of picture), and a bright zone in the south polar area (bottom of image) which could be an impact scar. ...

... The Porpoise Galaxy from Hubble . ... Just a few hundred million years ago, NGC 2936, the upper of the two large galaxies shown, was likely a normal spiral galaxy -- spinning, creating stars -- and minding its own business. ... Its exact full phase (June 23, 11:32 UT) will occur shortly before it reaches perigee, the closest point to Earth in the Moon's orbit, and make it the largest Full Moon of 2013. ... APOD Turns Eighteen . ... The first APOD appeared eighteen years ago today, on 1995 June 16. ...

... Bad Astronomy . ... Bitesize Astronomy . ... Bad Astro Store . ... Site Info . ... It is from from Voyager 1 and shows a whopping big impact crater dominating the profile of the moon. Note that Mimas is about 400 kilometers across (about 250 miles). ... The wall around the crater is 5 kilometers high, and that central peak rises 6 kilometers above the surface (many impact craters have a large central peak which is caused by a pressure rebound from the impact). ... 2008 Phil Plait. ...

... Astronomers once thought Pluto's atmosphere would condense down to the surface as it moved away from the Sun. Can that still be true, and if so, is that causing the surface features we now see? ... This is almost certainly because the atmosphere which is nitrogen, like Earth s atmosphere is also frozen as ice on the surface. ... Get instant access to subscriber content on Astronomy.com! ... If you are already registered on Astronomy.com, please log in below. ...

The coordinates, diameters, altitudes and morphological features of all the craters of Mars exceeding 10 km in diameter, totaling 19 308, are compiled. ... The catalogue is intended for use by investigators of Mars, students, in comparative planetology and in the selection of craters for naming. ... 1 one terrace . 2 many terraces . ... 6 many hills and one ridge . 7 one hill and many ridges . ... 1 one crater . 2 many craters . ... Sample craters of different morphological categories . ...

... The plug-plates of SDSS project are responsible for locating the optical-fiber plugs spatially and for defining the plug tilt with respect to the surface of best focus. ... Previous attempts to match the SDSS plug-plates to the surface of best focus were conducted using only the bending fixture. The analyses performed indicated that by adding a central constraint to the plug-plate deformation process, the plates could be made to match the surface of best focus within an acceptable range of error. ...

Astronotes Armagh Planetarium's Stellar Blog! ... This image combines orbital imagery with 3-D modelling to show flows that appear in spring and summer on a slope inside Mars' Newton crater. ... Warm season flows on a slope in Newton Crater, possible evidence of salty liquid water active on Mars today. Image credit: NASA) . ... Frozen water is common on and under the surface of Mars but these images are the best evidence to date for the presence of liquid water on the Martian surface today. ...

... LOCATION . ... The administrative centre, the library, scientific laboratories, computer center, hotel and apartment houses of an observatory are located in the settlement Nizhnij Arkhiz , which is situated in 25 kms to the south from a village Zelenchukskaya. ... It is desirable to come on conference by the following types of transport: . ... During the conference period it is supposed to conduct a public meeting of the section "Sun" with discussion of results of the researches made in 2005. ...