... Bad Astronomy . ... I think I will break from my usual format of Bad Astronomy/ Good Astronomy by saying that the way we define seasons currently is not strictly bad, but I feel (in my opinion!) that it could be better. The definition of when the seasons begin is at the moment of solstice or equinox; that is, winter (in the north) starts on December 22 nd and summer starts on June 22 nd . ... Now imagine breaking up the Sun's 46 degree up-and-down yearly swing into 1 day intervals. ...

We present new images of the reflection nebula surrounding the R Coronae Borealis Star, UW Centauri. ... Instead, the morphology of the nebula appears to change as different parts are illuminated by light from the central star that is modulated by shifting thick dust clouds near its surface. ... In this way, the central star acts like a lighthouse shining through holes in the dust clouds and lighting up different portions of the nebula. ... ADS Citation Query . citations = 21 . ...

... 4a. Electric Fluid . ... Field Lines . ... EM Waves . ... One could then define the unit of current, as the current which, when flowing in a straight wire, attracts a similar current in a parallel wire 1 meter away with a force of unit strength, for every meter of the wires' length. ... Faraday also showed that a magnetic field which varied in time--like the one produced by an alternating current (AC)--could drive electric currents, if (say) copper wires were placed in it in the appropriate way. ...

... 24sep08: long recovery vs alfa rotation angle. ... On 23sep08 around 14:00 hours data was taken with alfa on the sky to see how long the recovery took. ... 2 172 MHz Bands per beam . ... On 24sep08 around 17:00 data was taken with alfa and the pdev spectrometer to measure the long recovery time versus the rotation angle of alfa. ... As alfa rotates, different beams have larger/smaller recovery times. ... This is the same data as the total power plots above. beam 0 alfa rotation= 0 deg . ... page up ...

... 4a. Electric Fluid . ... Field Lines . ... EM Waves . ... One could then define the unit of current, as the current which, when flowing in a straight wire, attracts a similar current in a parallel wire 1 meter away with a force of unit strength, for every meter of the wires' length. ... Faraday also showed that a magnetic field which varied in time--like the one produced by an alternating current (AC)--could drive electric currents, if (say) copper wires were placed in it in the appropriate way. ...

... An Erupting Solar Prominence from SOHO . ... Still Life with NGC 2170 . ... Get out your red/blue glasses and gaze across Burns Cliff along the inner wall of Endurance crater on Mars! ... Methane Rain Possible on Titan . ... Recent analyses of measurements taken by the Huygen's probe that landed on Titan in 2005 January indicate that the atmosphere is actually saturated with methane at a height of about 8 kilometers. ... The largest canyon in the Solar System cuts a wide swath across the face of...

Next: The stage and Up: The ESO Red Sky Previous: Artefacts . Fig. 3 shows the distribution of stars. The most striking feature is the rapid steepening of the density gradient towards the Milky Way region at the right and left hand edges of the total field, apparent from the dramatic change in colour in this false colour presentation. Noticable changes in star density across even short distances are indicated by colour changes within individual plates. ... Fig. ...

Next: Release of 1 Dec. ... Fixed 04Jan98 RCW. Fix translation of VLA bandwidth code into an actual bandwidth. ... Fixed bug in SETFCAT, the routine that chooses the frequency catalog entry to use. ... Cleaning up code relating to setting scan times (before optimization). 17feb99 RCW. Count the number of times the tape stops. ... MINPAUSE causes the use of continuous tape motion if the tape stop time would between 2 scans would be less than MINPAUSE times the speed up factor. ... 26Feb99 RCW . ...

An Ancient Universe: How Astronomers Know the Vast Scale of Cosmic Time . THE CHANGING UNIVERSE: EVOLUTION HAPPENS! . b) Changes in Stars . One of the great discoveries of modern science is that stars (like people) live only a measurable life-time and then die. Although the lives of the stars are enormously longer than the span of a human life, we can learn about the life story of the stars by studying them at many different stages in their life cycle, from birth to death. ...

... April 13, 1998 . The Sun Changes . ... Explanation: Our Sun changes every day. This recent picture was taken in a very specific red color called Hydrogen-Alpha . Dark spots that might appear on the image are usually sunspots , dark magnetic depressions that are slightly cooler than the rest of the Sun's surface. Bright spots that might appear are usually plages , active regions that are slightly hotter than the rest of the Sun's surface. ... About APOD > . ...