... 2007 December 30 . Mammatus Clouds Over Mexico . ... Explanation: Normal cloud bottoms are flat because moist warm air that rises and cools will condense into water droplets at a very specific temperature, which usually corresponds to a very specific height. After water droplets form that air becomes an opaque cloud. Under some conditions, however, cloud pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate. ... About APOD | ...

Our group includes both theoreticians and observers working on problems related to many different aspects of star formation. You can learn more about us by following the links provided here below. We will try to keep these pages updated as frequently as possible, however do not hesitate to contact us directly if you encounter problems while browsing or do not find the specific information that you are looking for. Click on the following for more information . Our Group . ...

... HST Overview . ... CONTENTS: -Update on STIS Situation -Calibration Close-out Highlights -Doppler Correction Errors -Cross-dispersion Plate Scale Corrections -CALSTIS V2.17 Release Notes -Support for STIS Imaging Data in Multidrizzle -Recently published Instrument Science Reports (ISRs) -Fix for CALHRS flux error +----------------------------------------------------------+ Update on STIS Situation We provide an update on the current status of STIS operations and future plans for the instrument. ...

... Magnetic storms online . ... Geomagnetic activity forecast . ... December : 2015 . ... No magnetic storm is expected . From 2 December 2015 to 28 December 2015 the following magnetic storms and disturbances are expected: . December 06, 2015 geomagnetic disturbances . ... December 08, 2015 geomagnetic storm of level G1 (minor) . ... December 21, 2015 geomagnetic storm of level G2 (moderate) . ... December 16, 2015 geomagnetic storm of level G1 (minor) 2 December 2015 - 28 December 2015 . ...

... In spite of the good potential possibilities, some of the station "Dnepr" design characteristics did not allow us to apply the usual special IS radar measurement methods. ... Thus for IS signal measurements at the "Dnepr" station, we have developed special methods for recording and processing IS signals in order to determine plasma ionospheric parameters. ... Equations (4-5) from the basis for data post processing to obtain ionosphere parameters. ...

Astronomy Picture of the Day . ... 20.01.1999 . ... January 1999 . ... 1999 2000 . ... NASA Web Site Statements, Warnings, and Disclaimers . NASA Official: Jay Norris. ... A service of: LHEA at NASA / GSFC . ... U. Based on Astronomy Picture Of the Day . Publications with keywords: extrasolar planet - dust - infrared - young stars . Publications with words: extrasolar planet - dust - infrared - young stars . ... A Giant Planet for Beta Pic . Young Star Cluster Westerlund 2 . ...