... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Risks Comparable to NEOs . ... The Increasing Rate of Discovery of Asteroids . ... Comet and Asteroid Collision Probabilities . ... Extreme albedo comets and the impact hazard (PDF Format) . ... Asteroid Impact Animations . ... Workshop on Scientific Requirements for Mitigation of Hazardous Comets and Asteroids - 2002 . ... The Spaceguard Survey Report, 1992 (PDF) . Tsunami from Asteroid/Comet Impacts . ...

The OTA spherical aberration produces a Point Spread Function (PSF-the apparent surface brightness profile of a point source), as presented to the instruments, with broad wings. ... Figure 5.2 shows the encircled energy (EE), the proportion of the total energy from a point source within a given radius of the image center, for the same three cases. ... Encircled energy curves for other filters are shown in Figure 5.3 and Figure 5.4 ; note that these curves are normalized to unity at 1.0 " radius. ...

Plasma phenomena occuring at one place in the magnetosphere also affect other locations This linkage is most pronounced between points that share the same field line, since field lines guide the motion of ions and electrons. ... It follows that the places on Earth most sensitive to distant magnetic effects are the "polar caps" , the regions around the magnetic poles. A good example is the polar aurora . ... way polar field lines . ... and to the Sun . ... Next Stop: #26H. Polar Cap--History . ...

... In the first page of this chapter, Eddington computes an effective temperature of 3.18 K, but this has nothing to do with the 2.725 K blackbody spectrum of the Cosmic Microwave Background (CMB) . Here is a quote of what Eddington actually said: . ... We shall first calculate the energy density of this radiation. ... It is clear that Eddington's model fits the optical data, but that Eddington did not anticipate either the CMB (red curve) or the interstellar dust (ISD, green curve). ...

... How much energy is there in a 20 mph wind? . 20 mph wind =10 m/s .0006 * 10 3 = .0006 * 1000 = .6 KILO watts per square meter . ... In your back yard the average wind speed is 10 mph which yields 100 watts per square meter. ... 4 3 = 64 if a 10 mph wind gives you 100 watts per square meter then a 40 mph wind gives you 64 times more power per square meter 6400 watts per square meter . total power = 6400 watts per square meter * 2 square meters = 12800 watts = 12.8 Kilowatts this is a lot! ...

Astronomy Picture of the Day . ... Our Milky Way galaxy appears to be surrounded by a halo of gamma rays. ... Blue Stagglers in Globular Clusters . ... Irregular Moons Discovered Around Uranus . ... Where did these two irregular moons of Uranus originate? Last week two previously undiscovered moons of the distant gas planet were confirmed, the first in irregular orbits. ... Most of these were discovered by the passing Voyager 2 spacecraft in 1986. ... M31: The Andromeda Galaxy . ...

The Star called the Sun. The Sun as the star . ... The visible star value . ... Spectrum class . ... 149 597 870 km . ... The Solar energy sourse is the core transformation of the Sun, where temperature is 15 000 000 K. The energy from inside is carried by irradiation and then in the external layer with 0,2 Ra of thikness - by convection. ... The Earth, situating far from the Sun (149 mil km), receives about 2.1017 W of the Solar beam energy (see item "The Solar constant" ). ...

Main Sections LabIR main page . ... On January 23, 1998 the space probe NEAR was on its way to its closest approach to Earth. ... However, we were able to record a series of images of the space probe shortly before the sunglint event, and we have assembled them into a movie. At the TIRGO observatory, an observation of the space probe NEAR was organized for the night of January 22-23, 1998. ... We show here a preliminary movie (MPEG format, 412kb) made from 74 frames, each lasting 5 seconds. ...

Next: Rapidly Rotating Stars Up: Discussion Previous: Relations . ... They attributed this to a mechanism which regulated stellar angular momentum through the accretion disk. ... While some of this may be due to sampling effects, the data seem to indicate that after a star loses its disk, either it continues its slow rotation for a period of time and then a rapid increase in rotation rate commences or spin up does not necessarily follow the loss of the disk. ...

... Bad Astronomy . ... Every few months, one of a series of questions comes up on the USENET group sci.astro involving tides, or the rotation of the Moon, or the recession of the Moon from the Earth. ... Why the Moon's rotation period is the same as the length of time it takes to orbit the Earth (same as number 1, but phrased differently). ... But when this happens, the time it takes for the Earth to rotate once will be slowed to exactly the same time it takes for the Moon to go around the Earth once! ...

... We have developed an integrated system that performs astronomical observations in Near Infrared bands operating two-dimensional instruments at the Italian National Infrared Facility's ARNICA and LONGSP . ... The user interface is organized as widget-based X11 client. ... 1993; Di Giacomo et al. 1993). ... Moreover, if the interprocess communication interface includes support for networking, the software immediately becomes network distributed software. ... DESQview/X User Guide 1993, Quarterdeck . ...

... November 7, 1997 . Evidence for Frame Dragging Black Holes . ... According to recent measurements of a star system thought to contain a black hole , it can spin you too. ... Now, a team led by W. Cui ( MIT ) has used the orbiting Rossi X-ray Timing Explorer to search for it near a system thought to contain a black hole . Cui's team claim that matter in this system gets caught up and spun around the black hole at just the rate expected from frame-dragging. ... About APOD > . ...

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. ...

... The Sun gives us light and heat, sustaining life on Earth. ... This uneven rotation, coupled with the churning of the upper layers, might well be what produces (by a "dynamo mechanism", described in a later section) regions of intense magnetic field, seen by observers on Earth as dark sunspots. ... Near sunspots those streamers seem to be shaped by the Sun's magnetic field lines, and above the Sun's poles they suggest field lines rising from twin magnetic poles like those of the Earth. ...

The program "Pioneer" . Pioneer - 10", the first space vehicle started in March, 1972 to the Jove, has reached . ... This photo of the Jove was received December, 1, 1973 when space probe " pioneer - 10 " has come nearer to a planet on distance 2,5 million km. ... This photo was received by "Pioneer - 11" December, 6, 1974 from distance 1,1 million km from a planet. ... The picture is received in December, 12, 1974 when "Pioneer - 11" was on distance of 1207 thousand kms from the Jove. ...

... The general term for these waves is "Electromagnetic Waves". ... ASTR1001 Wavelengths · Electromagnetic waves, while all travelling at the same speed, can have different wavelengths (the distance between the crest of one wave and the next). ... Red Light: Wavelength 700nm Green Light: Wavelength 550nm Blue Light: Wavelength 400nm Ultra-Violet Light: Wavelength 300nm ASTR1001 The Electromagnetic Spectrum · Electromagnetic waves can have any wavelengths at all: anywhere from picometres to light-years....

... The current MOS procedure envisages a less complicated correction mechanism than for the PN. ... The CTI correction applies a scalar correction to the event list set, on an event by event basis, in order to correct for loss of charge which has occurred in reading out the CCD array. ... We expect to correct for a fixed amount of charge loss, and a fractional amount of charge loss, which depends on the number of row and column transfers completed. ... http://xmm.vilspa.esa.es/ xmmdoc/MOS/mos_cti.html ...

... Science User Portal . ... ESO, the European Southern Observatory . ... Travel and Contacts . Travel to ESO Headquarters . ... Travel to Guesthouse . ... Survey Telescopes . ... This video fades back and forth between views of the stellar nursery Monoceros R2 in visible and infrared light. The visible-light view was created from digitised photographs through red and blue filters forming part of the Digitized Sky Survey 2 (DSS) and the new infrared view comes from the VISTA telescope at Paranal. ...

... COMPUTER SIMULATION OF RADIOWAVE MULTIPLE SCATTERING EFFECTS IN IONOSPHERE USING MONTE-CARLO METHOD . ... Distribution of reflected radiation on the ground is computed. ... Such influence can be remarkable if the scattering is multiple, i.e. the optical thickness for the scattering process is considerably greater than a unit. ... Radiation energy transfer in the slab is modeled by distribution of some particles carring small portions of radiation energy. ... The isotropic plasma approximation is...