次世代宇宙望遠鏡、初の天体撮影　「セルフィー」も

【ワシントンＡＦＰ＝時事】米航空宇宙局（ＮＡＳＡ）は１１日、同局の次世代宇宙望遠鏡「ジェームズ・ウェッブ宇宙望遠鏡」が、打ち上げ後初となる天体画像とセルフィー（自撮り写真）を撮影したと発表した。（写真はジェームズ・ウェッブ宇宙望遠鏡がおおぐま座にある恒星を撮影した画像。複数の画像を組み合わせて作成。米航空宇宙局＜ＮＡＳＡ＞提供）
　撮影は、ウェッブ宇宙望遠鏡が搭載した巨大な黄金色の主鏡を調整する作業の一環として行われた。鏡の調整は数か月間にわたり行われる。
　初となる画像に捉えられたのは、おおぐま座に位置し、他の天体から離れて輝く恒星「ＨＤ ８４４０６」。黒の背景に、主鏡を構成するセグメント１８枚がそれぞれ捉えた１８個のぼやけた白い点が写されている。決して見事な写りとは言えないが、正式運用に向けた一歩としては重要な成果だ。
　同望遠鏡の主要観測機器の主任研究員で、米アリゾナ大学天文学部教授のマーシャ・リーケ氏は、「画像撮影と望遠鏡の調整の初期段階がこれほど順調に進んでいることに、ウェッブのチーム全員が感激している」と表明した。
　調整の一環として、望遠鏡外部のカメラではなく、主要観測機器に搭載された特殊レンズで「セルフィー」も撮影された。ＮＡＳＡは以前、自撮りは不可能だと説明していたことから、宇宙ファンにとってはうれしいニュースだ。カメラ機器を担当するチームの責任者は電話会見で、星の光だけでこのような画像を撮れるか確証が取れなかったことから、撮影成功は驚きだったと語った。
　ウェッブ望遠鏡は今年夏までに科学調査ミッションを開始する予定。高解像度の観測装置を用いて、１３５億年前の宇宙誕生初期の様子を調べるため、ビッグバン直後に誕生した銀河を観測することを目指している。【翻訳編集ＡＦＰＢＢＮｅｗｓ】

〔ＡＦＰ＝時事〕（2022/02/15-11:13）

Star light, star bright, the James Webb Space Telescope has seen its first star (though it wasn't quite tonight) -- and even taken a selfie, NASA announced Friday.
The steps are part of the months-long process of aligning the observatory's enormous golden mirror that astronomers hope will begin unraveling the mysteries of the early Universe by this summer.
The first picture sent back of the cosmos is far from stunning: 18 blurry white dots on a black background, all showing the same object: HD 84406 a bright, isolated star in the constellation Ursa Major.
But in fact it represents a major milestone. The 18 dots were captured by the primary mirror's 18 individual segments -- and the image is now the basis for aligning and focusing those hexagonal pieces.
The light bounced off the segments to Webb's secondary mirror, a round object located at the end of long booms, and then to the Near Infrared Camera (NIRCam) instrument -- Webb's main imaging device.
The entire Webb team is ecstatic at how well the first steps of taking images and aligning the telescope are proceeding, said Marcia Rieke, principal investigator for the NIRCam instrument and regents professor of astronomy, University of Arizona, in a statement.
We were so happy to see that light make its way into NIRCam.
The image capturing process began on February 2, with Webb pointing at different positions around the predicted location of the star.
Though Webb's initial search covered an area of the sky about equal to the size of the full Moon, the dots were all located near the center portion, meaning the observatory is already relatively well positioned for final alignment.
To aid the process, the team also captured a selfie taken not through an externally mounted camera but through a special lens on board NIRCam.
NASA had previously said a selfie wasn't possible, so the news comes as a welcome bonus for space fans.
I think pretty much the reaction was holy cow, Lee Feinberg, Webb optical telescope element manager, told reporters in a call, explaining that the team wasn't sure it was possible to obtain such an image using starlight alone.
The $10 billion observatory launched from French Guiana on December 25 and is now in an orbit that is aligned with the Earth's around the Sun, one million miles (1.5 million kilometers away) from our planet, in a region of space called the second Lagrange point.
Webb will begin its science mission by summer, which includes using its high resolution instruments to peer back in time 13.5 billion years to the first generation of galaxies that formed after the Big Bang.
Visible and ultraviolet light emitted by the very first luminous objects has been stretched by the Universe's expansion, and arrives today in the form of infrared, which Webb is equipped to detect with unprecedented clarity.
Its mission also includes the study of distant planets, known as exoplanets, to determine their origin, evolution and habitability.