... In principle, two observers on the ground can tell, by comparing the position of the same auroral arc against the background stars. ... The display stretches across Canada; just below it, in the middle of the picture, are the lights of Chicago, next to Lake Michigan. ... The Canadian scientific satellite Isis-2 (1971) carried an auroral imaging camera and discovered the diffuse aurora, a broad ribbon around the auroral oval, too spread-out to be noticed from the ground. ... Auroral Acceleration . ...

... Spacecraft . 29b. Satellites looking down . ... 29e. Explorers of distant space . ... The Hubble orbiting telescope. ... The Hubble telescope , in low Earth orbit, overcomes such limitations, in the visible range and in part of the UV. ... So fruitful was this observation that a second "deep field" exposure of such length, near the southern pole of the heavens, was recently conducted. ... Some satellites specialize in observing the Sun, such as the Japanese Yohkoh and NASA's SOHO . ...

... Orion's Horsehead Nebula . ... It is visible as the black indentation to the red emission nebula seen just to the right of center of the above photograph. The bright star near the center is located in the belt of the familiar constellation of Orion. ... The Year of Distant Supernovae . ... Supernova 1994D and the Unexpected Universe . ... Supernova 1994D, visible as the bright spot on the lower left, occurred in the outskirts of disk galaxy NGC 4526. ... NEAR to Asteroid Eros . ...

Astronomers at Armagh Observatory observed the partial eclipse of the Sun on 29 March under unusually good conditions. ... The images, taken by astronomer Miruna Popescu, shows the eclipse as seen from the Armagh Observatory at around 11:30 (Summer Time) on 29th March, and the way it was observed by astronomer Apostolos Christou with a small portable telescope equipped with a filter to protect against the Sun's dangerous radiation. ... For more images from Armagh see: Miruna Popescu's Pages . ...

... Tonight's Sky . ... The Magazine . ... Observing . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... Bright planets meet at dusk . ... Astronomy magazine subscribers can read the full article for free. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

It is possible to piece together the processes that have shaped the observed characteristics of a galaxy by studying its stars in detail. The Large Magellanic Cloud (LMC) is an excellent candidate for this type of study because of its favourable viewing angle and ongoing star formation. I present the results of high-resolution VLT/FLAMES observations of ~80 red giant stars around star cluster NGC 1846, located in the disc of the LMC. ...

... Fitting the observed dependence includes calculations of the polarization cross-sections averaged over particles orientation and size distribution, their normalization and the comparison of obtained dependencies with Serkowski's curve representing observational data for a chosen star. ... Variations of the polarization factors with wavelength are shown in Fig. 16 for homogeneous spheroidal particles with PF orientation. ... The distinction between prolate and oblate spheroids is also clearly seen. ...

... Actual stars are expected to be more complicated than these simulations. ... The spot may be entirely visible most of the time (one would observe a prolonged flux minimum low), and then part of it may disappear over the horizon briefly and then return (slow rise and then fall back to constant level). ... With the set of observations taken here, I have information available from several comparison stars and color information. ... The period found must be consistent with the data from any given night....

... Information about a variety of different calendars for different cultures (e.g., Christian, Jewish, Muslim, Chinese, Hindu etc.) ... In addition, the Chinese had two different ways of interpreting and observing celestial events. One way the Chinese used astronomy was known as lifa; it was a discipline that aimed to understand the regularities and the predictable events in the celestial system through careful, observations, measurements and records. ... back to Teachers' Newsletter Main Page ...