国立天文台

• 科学・IT

For an observatory which observes the night-sky day after day, it is important to have good weather throughout the entire night. This is an all-sky scene of a clear spring night as seen by the Okayama Astrophysical Observatory sky monitor. As stars make their daily rotation around the north celestial pole, their light-trails stretch from east to west. The lights that run in straight lines with different directions from the stars and appear for only short periods of time are airplanes flying across the sky. The light surrounding the image low in the sky is the bright glow of artificial illumination from the Setouchi industrial district and extensive urban development. This light pollution creeps into even leading-edge domestic astronomy observations which peer into the abyss of outer space.


日々夜空の観測を続ける観測所にとって、一晩中天候に恵まれる夜は貴重なもの。岡山天体観測所のスカイモニターが見つめた、ある晴れた春の一夜の全天の情景です。天の北極を中心に日周運動する星の光跡が、東から西へと伸びていきます。星の動きとはまったく違う方向に短い時間で直線的に走る光は、夜空を飛び交う航空機。画面周囲の低い空は瀬戸内工業地帯や大規模な市街地からの人工照明によって明るく照らされています。宇宙の深淵をのぞき込む天体観測の国内最前線にも、光害が忍び寄っています。