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Mount Moran 慕銳山 (1/9/2003)
又是風景相一張，沒什麼好說的了。這裏是美國西部懷俄明州的大特頓國家公園，當中的慕銳山。其實到美國來一次自助旅行，就可以暢遊去各不同的國家公園，一想到這裏，就不其然興奮起來。

Caption:: This is another nature scene picture. It is the Mount Moran, Grand Tetons, Wyoming, USA. If we have time, do try to walk through the national parks of US and we will see a lot of wonderful scenes.

Credit:: Sharon Gerig

Nebula around AB7 圍繞AB7之星雲 (31/8/2003)
一直以來，都介紹過不少星雲，如果大家平時有看的話，應該知道其中一種星雲叫發射星雲，是一些自己懂得發光的星雲來的。而這些星雲會懂得發光，是因為星雲當中的粒子都因為經常被撞到而掉失電子，變成離子，跟著這些離子重新捕捉到電子而放出光。但宇宙中也有另人費解的星雲，圖中是其中一個暫時天文學家未了解成因的星雲。這個星雲是沒有名字的，它的電離程度異常的高，跟正常的星雲不同，相信是由裏頭的雙星AB7而造成，令星雲的電離程度異常的高。

Caption::
The photo is a reproduction of a "near-true" three-colour composite image of the highly excited nebula around the hot double star AB7 in the Small Magellanic Cloud (SMC), obtained in January 2002 with the FORS1 multi-mode instrument at the 8.2-m VLT MELIPAL telescope at the Paranal Observatory (Chile). It is based on three exposures through narrow-band optical (interference) filters that isolate the light from specific atoms and ions. In this rendering, the blue colour represents the light from single ionized Helium (He II; wavelength 468.6 nm; exposure time 30 min), green corresponds to doubly ionized oxygen ([O III]; 495.7 + 500.7 nm; 5 min) and red to hydrogen atoms (H; H-alpha line at 656.2 nm; 5 min). Of these three ions, He II is the tracer of high excitation, i.e. the bluest areas of the nebula are the hottest. The sky field measures 400 x 400 sq. arcsec; the original pixel size on the 2k x 2k CCD is 0.23 arcsec. North is up and east to the left. Before combination, the CCD frames were flat-fielded and cleaned of cosmic-rays. Moreover, the stars in the blue (He II) image were removed in order to provide a clearer view of the surrounding nebular emission. The reproduced brightness is proportional to the square-root of the actual intensity; this increases the "dynamical range" of the image, i.e. it shows better areas of very different brightness.

Credit:: European Southern Observatoty

Zebra 斑馬 (30/8/2003)
平時有否看生物的紀錄片？很多時候會看到非洲大草原的描寫，而斑馬就是其中一個很常見的動物。斑馬是群居的動物，主因是跟身上的斑紋一樣，為了保護自己，由於草原上的捕獵者太多了，牠們要靠數量多來分散捕獵者的注意力。但在群體的生活中，少不免也要社交，原來互相擦頸就是牠們的社交禮儀。

Caption:: Do you watch wildlife documentaries? Very often, there is some related to African wildlife, which would include zebra, our pic of the day. Zebras live together can protect themselves against predators. In the would nuzzle each other as part of a greeting and identification ritual in the community.

Credit:: Anup and Manoj Shah

Sunset on Mars 火星日落 (29/8/2003)
難得火星這麼近，所以都忍不住再貼上火星的圖來，請不要見怪呢。最近，火星都成了大家的焦點，我想大家都一定有想過將來人類移民到火星時會變成怎樣，雖然始終覺得人類拋棄地球不是太對，但這應該也是無可避免。到時人類在火星將會看到另一片星空，不是因為火星上的星座變了樣，而是火星的天空的顏色不同了，火星的天空是橙褐色的，日落時的顏色會變色藍色，就好像火星探路者號在火星上拍回來的相一樣，上圖的顏色是真色來的的。那麼，看來，還是地球的日落比較美麗。

Caption:: The brownish gray sky as it would be seen by an observer on Mars in this four-frame, true color mosaic taken on sol 24 (at approximately 1610 LST). The twin peaks can be seen on the horizon. The sky near the sun is a pale blue color. Azimuth extent is 60° and elevation extent is approximately 12°degrees.

Credit:: NASA / JPL

Mars V 火星 V (28/8/2003)
火星，你今日看左未？(跟昨天的開場白一樣呢)今天是火星大衝的日子，不能不看的六萬年一次的大大粒火星呢，不過聽到太空館有三千人排隊，感覺真奇怪(心想，香港真喜歡排隊)。今天也是，詳細的解釋在英文解說有了，所以不重覆了。

Caption:: NASA's Hubble Space Telescope took this close-up of the red planet Mars when it was just 34,648,840 miles (55,760,220 km) away. This color image was assembled from a series of exposures taken between 6:20 p.m. and 7:12 p.m. EDT Aug. 26 with Hubble's Wide Field and Planetary Camera 2. The picture was taken just 11 hours before the planet made its closest approach to Earth in 60,000 years.

Many small, dark, circular impact craters can be seen, attesting to the Hubble telescope's ability to reveal fine detail on the planet's surface. One of the most striking is the 270-mile- (450-km-) diameter Huygens crater, seen near the centerof the image.

The two dominant dark swatches seen on this part of the planet are classical regions labeled by early Mars observers. The "shark-fin" shape to the right is Syrtis Major. The horizontal lane to the left is Sinus Meridani. One of NASA's Mars Exploration Rovers, named "Opportunity," will land at the western end of this region in January 2004.

The picture shows that it is a relatively warm summer on Mars, as evident in the lack of water-ice clouds at mid-latitude, and the receding southern polar cap. Ice on the rugged topography gives a somewhat ragged, scalloped look. Up north, at the top of the disk where it is Martian winter, a frigid polar hood of clouds covers the northern polar cap and surrounding region.

Even in the relatively balmy Southern Hemisphere, daytime highs are just above freezing in the Hellas impact basin, the circular feature near the image center. Hellas is nearly 5 miles deep (8 km). Hellas is like Death Valley – except that Mars is much drier than even Death Valley. Having a diameter of 1,100 miles (1,760 km), Hellas was formed when an asteroid slammed into Mars billions of years ago. Many summer dust storms originate in this basin, though it is remarkably clear of dust in this Hubble image.

Mars and Earth have a "close encounter" about every 26 months. These periodic encounters are due to the differences in the two planets' orbits. Earth goes around the Sun twice as fast as Mars, lapping the red planet about every two years. Both planets have elliptical orbits, so their close encounters are not always at the same distance. In its close encounter with Earth in 2001, for example, Mars was about 9 million miles farther away. Because Mars will be much closer during this year's close approach, the planet appears 23 percent bigger in the sky.

This photograph is a color composite generated from observations taken with blue, green, and red filters. The resolution is 8 miles (12 km) per pixel.

Credit:: NASA, J. Bell (Cornell U.) and M. Wolff (SSI)

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