... In temperate latitudes, this is a good time to see halos formed by clouds of ice crystals high in the atmosphere where the temperature is always well down below -30 deg. ... The most prominent halos, however, appear quite close to the sun where it can be uncomfortably bright to look. ... In a sense, halos are like rainbows, glories and coronae in that they require the presence of a bright source of light, the Sun or the Moon, and water floating in the air. ...

... Because of the Earth 's gravity, atmosphere is horizontally stratified (see, e.g., Kelley, 1989). Its structure can be organized by using the neutral gas temperature, as shown in the figure from mid-latitudes (note the logarithmic altitude scale). When going upward from the ground within the lowermost atmospheric region, troposphere, the temperature decreases up to about 10 km altitude (tropopause). ... Here the radiation also ionizes the neutral atmosphere, creating the ionosphere . ... 1989. ...

... The related observations clearly evidence both global motions and turbulence in the upper Jovian atmosphere. Keywords: solar system, giant planets, atmospheres, Jupiter . To explain both an upper atmospheric thermal excess observed in the Jupiter atmosphere by the Voyager missions and a permanent enhancement of the H Ly- brightness observed near the equator (Clarke et al. ... These Doppler shifts appear as being the signature of global H motions in the upper atmosphere of Jupiter. ...

... The Armagh Observatory (see http://star.arm.ac.uk/ ) is the oldest continuously functioning astronomical research institute in the UK and Ireland, having been in existence for more than 210 years. ... The Astropark, which is managed by the Observatory, includes two sundials, a number of outdoor exhibits and interpretation panels (see http://star.arm.ac.uk/astropark/ ), and scale models of the solar system and the larger Universe, constructed to linear and exponential scales respectively. ... Staff ....

Next: Photometric Corrections Up: Long-Slit and 1D Previous: Long-Slit and 1D . This chapter describes the long-slit љ reduction package in a general way. ... The package provides about 50 basic commands to perform the calibration and to display the results, defined in the context LONG . ... The context SPEC is a low-level context including general utility commands required by the different spectroscopy packages ECHELLE , IRSPEC and LONG . ... This interface is described in the Appendix . ...

Next: CCD Operation Up: Charge Coupled Devices (CCDs) Previous: Charge Coupled Devices (CCDs) . ... However it is only now that a number of important X-ray astronomical applications of CCDs have reached critical development stages, so that this is an appropriate time to review the application of space-borne CCD instruments to cosmic X-ray astronomy, and highlight the particular concerns which are being addressed for X-ray instruments, as distinct from optical applications. ...

Getting To Know Layers . ... Layers in an image can be any size. ... You have the ability to toggle the visibility of a layer, so that it does not contribute to the final image. ... The layers dialog, with the Ops menu expanded . The primary tool for working with layers in GIMP is the Layers dialog. This gives you an overview of all the layers in an image, and provides the toggled areas for linking and visibility. ... You can also toggle a layer's Preserve Transparency option. ... Step 1 | ...

... ATNF Home . About ATNF . ... About ATNF overview . ... Australia Telescope Steering Committee . ... Australia Telescope User Committee . ... Astrophysics graduate student programs . ... Australian Square Kilometre Array Pathfinder . Murchison Radio-astronomy Observatory . ... Parkes radio telescope . Australia Telescope Compact Array . Mopra radio telescope . ... Visiting Parkes radio telescope . Visiting Australia Telescope Compact Array . ... Parkes radio telescope webcam . ...

Next: The course and unit level Up: Ceilidh - On Line C Tutoring System Previous: Introduction . ... To enter the system at the general level, the appropriate command (which should have been set up by your computer systems administrator) is . ... q quit this session fs find student | ... text ceilidh only) in X the courses available appear on main window.This command tells you which courses are available and supported by the Ceilidh system, their full title and their abbreviation. vp . ...

... Sagittarius Dwarf Irregular Galaxy . ... How old is this galaxy? The nearby Local Group galaxy dubbed the Sagittarius Dwarf Irregular Galaxy (SagDIG) is not only very small but also has relatively few elements more massive than helium. ... Moon Over Shiraz . ... Early morning risers around the world have enjoyed the sight of bright planets in this week's predawn skies - further enhanced by the celestial spectacle of the waning crescent Moon. ... Leo A: Nearby Dwarf Irregular Galaxy . ...

... The eleven years cycle of Sun's activity is approaching its maximum! From August 24th to 29th a team of astronomers, engineers and astro-photographers will travel to southern Greenland to observe the Northern Lights (Aurora Borealis), a phenomenon expected to be particularly spectacular during this period. ... Auroras . The wonderful celestial spectacle of the aurora occurs when very energetic particles from the Sun reach the Earth's atmosphere via the solar wind. ... About GLORIA . ...