LAMOST 为什么放弃传统插板方式,改用并行控制的光纤定位单元来分配光谱仪光纤?
Why does LAMOST assign spectrograph fibers with parallel-controlled robotic positioners instead of traditional plug plates?
插板需要在白天人工钻孔并逐根插入光纤,一夜之内无法切换数千个观测目标。LAMOST 在五度直径的焦面上布设了4000个双轴微步进定位单元,由计算机按目标表并行驱动,几分钟内即可完成全焦面重构,单次曝光获得数千条低分辨率光谱。这一设计使其长期位居单次曝光获取光谱数最多的望远镜之列,支撑起千万量级的恒星光谱巡天。
Plug plates must be drilled and hand-plugged during daytime, so thousands of targets cannot be swapped within a single night. LAMOST instead deploys 4000 dual-axis micro-stepper units across its five-degree field of view, driven in parallel from a target catalog to reconfigure the whole focal surface within minutes and record several thousand low-resolution spectra per exposure. The design kept it among the telescopes capturing the most spectra per exposure, powering stellar surveys totaling tens of millions of spectra.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
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出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
Cui 等(LAMOST 团队),2012年,Research in Astronomy and Astrophysics,12卷1197页:LAMOST 先导试验观测报告
Cui et al. (LAMOST team) 2012, Research in Astronomy and Astrophysics, 12, 1197 - Preliminary LAMOST experiment
#光纤定位技术 #光谱巡天
巡天望远镜为什么普遍采用漂移扫描模式来覆盖大片天区？
Why do many survey telescopes use drift-scan mode to cover large areas of sky?
地球自转让所有天体以恒星日速率匀速掠过望远镜视场，漂移扫描让CCD以同一速率连续转移电荷读出，相当于让探测器与天空同速移动。这样不需要昂贵的跟踪转台和大视场拼接停顿，一条长条带可以整夜不间断地记录下来，占空比接近百分之百。斯隆数字巡天等大规模测光巡天正是靠这一模式高效积累了上亿个源的多波段测光。
Earth's rotation carries every source across the field at the sidereal rate, and drift scanning shifts CCD charge along at that same speed so the detector effectively tracks the sky electronically. This avoids costly precision tracking and stop-and-go mosaic pointing: one long strip can be recorded continuously all night at nearly full duty cycle. Large photometric surveys such as the Sloan Digital Sky Survey used exactly this mode to accumulate multi-band photometry for hundreds of millions of sources.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
SDSS 概念设计文档与 York et al. 2000年SDSS总述论文；Gunn et al. 1998年SDSS相机论文
York et al. 2000 SDSS overview paper; Gunn et al. 1998 paper on the SDSS imaging camera
#漂移扫描 #测光巡天
一位聋哑女计算员如何量出了整个宇宙的距离?造父变星的秘密
How did a deaf woman computer measure the universe? The secret of Cepheid stars.
1900年代哈佛天文台的计算员亨丽爱塔·勒维特研究麦哲伦云中的变星,在1777颗样本里确认了25颗造父变星,并发现关键规律:造父变星的光变周期越长,平均亮度越高——由于云内成员距离相近可视为同处一线,周期与光度的严格关系由此确立。这意味着造父变星是自带标尺的灯:测出周期得到真实亮度,再比观测亮度即可反推距离,几百万光年外也能丈量。哈勃正是用它确认仙女座在银河系之外,并进而发现宇宙膨胀。聋哑的她生前署名权寥寥,如今造父变星被称为宇宙距离阶梯的第一级横档。
Around 1908 the Harvard computer Henrietta Leavitt, working through a sample of 1,777 variable stars in the Magellanic Clouds and picking out 25 Cepheids among them, found the key law: longer-period Cepheids shine brighter on average, and since Cloud members share one distance the period-luminosity relation held strictly. Cepheids became lamps carrying their own rulers: read the period for true brightness, compare with apparent brightness, invert for distance millions of light-years away. Hubble used them to place Andromeda beyond our galaxy, then discovered cosmic expansion. Deaf and barely credited alive, Leavitt now names the first rung of the cosmic distance ladder.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Leavitt 与 Pickering,《Periods of 25 Variable Stars in the Small Magellanic Cloud»,Harvard College Observatory Circular 第173卷,1912
H. S. Leavitt and E. C. Pickering, Periods of 25 Variable Stars in the Small Magellanic Cloud, Harvard College Observatory Circular 173, 1912
独立核验依据 · Independent verification: 核验依据 1 INSPIRE 标识 inspire:1088524：Periods of 25 Variable Stars
#造父变星 #周光关系 #宇宙距离阶梯
什么是天文巡天？举一个例子。
What is an astronomical survey, and give an example.
巡天是用望远镜系统性地扫描大片天区、积累海量天体目录的工作，例如斯隆数字巡天（SDSS）绘制了数百万星系和类星体的图谱。
A survey systematically scans large sky areas to build vast catalogs of objects; the Sloan Digital Sky Survey (SDSS), for instance, mapped millions of galaxies and quasars.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Zeilik,《Astronomy: The Evolving Universe》第9版,Cambridge University Press,2002
M. Zeilik, Astronomy: The Evolving Universe, 9th ed., Cambridge University Press, 2002
#巡天 #目录 #星系