星空故事：你見過人造衛星？

放大圖片

　一艘在離地面200至350千米高空運行的飛船，比如說只長9米的神舟七號，你看得見嗎？答案是否定的。不過，當衛星或飛船於剛入黑後或日出前飛掠香港的上空，我們還是有機會憑藉它反射的太陽光線和移動速度，在黑暗的星空中把它認出來。至於國際太空站和穿梭機這類巨大的軌道飛行器，更可使用天文望遠鏡觀測並辨別其形狀。附圖是我於2006年使用直徑12厘米望遠鏡拍得國際太空站橫過太陽面的連續過程，影像顯示太空站的太陽能電池板及起居艙的外形。注意：肉眼觀測太陽可導致失明，千萬不可嘗試！

Have you ever seen a satellite?

　Do you think you can spot a satellite, such as the nine-metre Shenzhou spacecraft, that is flying 200 km high above? As a matter of fact, you can, taken that it happens to transit your local sky within an hour or two after sunset or before sunrise. You can identify it by the sunlight it reflects. For huge objects such as the International Space Station (ISS) and the Space Shuttle, their shapes can even be discerned through an astronomical telescope. The above picture is one I took in 2006 when the ISS happened to transit the face of the sun. However, peeping the sun through a telescope can cause permanent damage to your eyes! 　■甄枝強　資深天文愛好者