DECaPS2 contains 3.32 billion objects built from 34 billion detections. The detections are in 21,400 exposures which added up to 260 hours of open shutter time with the Dark Energy Camera (DECam) at the Cerro Tololo observatory. Of the 3.32 billion objects, about 2 billion are stars. It took two years and produced over 10 terabytes of data. The first data set was released in 2017, and it contained 2 billion objects, most of which were also stars
https://www.universetoday.com/159724/a-new-survey-of-the-milky-way-reveals-billions-of-objects-helping-to-map-our-surroundings-in-three-dimensions/https://tech.news.am/eng/news/686/scientists-create-milky-way-stars-new-map-on-which-there-are-33-billion-objects.htmlScientists create Milky Way stars’ new map on which there are 3.3 billion objects
最新銀河系星圖出爐! 科學家公布「巨大」銀河系星圖 可識別33億顆恆星
https://tw.news.yahoo.com/%E6%9C%80%E6%96%B0%E9%8A%80%E6%B2%B3%E7%B3%BB%E6%98%9F%E5%9C%96%E5%87%BA%E7%88%90-%E7%A7%91%E5%AD%B8%E5%AE%B6%E5%85%AC%E5%B8%83-%E5%B7%A8%E5%A4%A7-%E9%8A%80%E6%B2%B3%E7%B3%BB%E6%98%9F%E5%9C%96-%E5%8F%AF%E8%AD%98%E5%88%A533%E5%84%84%E9%A1%86%E6%81%86%E6%98%9F-091756996.html據最新一期《天體物理學雜誌增刊》刊發的論文，天文學家日前發佈了一張 33 億多顆恆星的巨大銀河系星圖，該照片是由智利一間天文台望遠鏡上的暗能量相機（DECam）所拍攝，這份星圖耗時兩年完成，對銀河系 21,400 次單獨曝光產生了超過 10TB 的數據，儘管其規模龐大，該調查仍然只覆蓋了夜空的 6.5％。
由於氣體和塵埃構成的黑暗卷鬚吸收星光遮住了微弱的恆星、星雲的光則阻礙了測量物體的亮度、加上龐大的恆星數量出現重疊現象等因素讓這項調查困難重重，但研究人員還是透過近紅外光下觀察銀河平面來應對此問題。
對此，美國國家科學基金會天文科學部主任費舍爾（Debra Fischer）表示，天文學家們將「在未來的幾十年裏仔細研究銀河系中 30 多億顆恆星的這幅詳細畫像」，他認為這是一項技術壯舉，「想像一下，一張超過 30 億人的合影，而每一個人都是可以被識別的。」
