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  • richardmitnick 11:34 am on November 30, 2020 Permalink | Reply
    Tags: "LAMOST-Kepler/K2 Survey Announces the First Light Result", , , , , Kepler photometry, LAMOST-Kepler project, , , Spectrographs,   

    From National Astronomical Observatories of China (CN) and phys.org: “LAMOST-Kepler/K2 Survey Announces the First Light Result” 

    From National Astronomical Observatories of China (CN)

    at

    Chinese Academy of Sciences (CN)

    and


    From phys.org

    An international team led by Prof. Jian-Ning Fu and Dr. Weikai Zong, from Beijing Normal University, published the first light result of medium-resolution spectroscopic observations, which is undertaken by the LAMOST-Kepler/K2 Survey.

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    Phase II of the LAMOST-Kepler/K2 Survey.

    This result demonstrates that the medium-resolution spectrographs, equipped on LAMOST, perform to the designed expectation. The article is published this November online in the Astrophysical Journal Supplement Series.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018.

    The LAMOST-Kepler/K2 Survey [science paper above] was launched based on the success of the LAMOST-Kepler project [RAA], a low-resolution spectroscopic survey that consecutive performed since 2011.

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    From LAMOST-Kepler project. Targets of scientific interest in the field of view (FOV) of the Keplermission. The black dots refer to the centers of the 14 LK-fields that cover the KeplerFOV. The following color coding is used: green for standard targets, blue for KASC targets, and orange for planet targets. The LK-fields observed in 2011–2014 are indicated by the circles drawn with a full line going from thick to thin and from gray to black, respectively.

    Different from LAMOST-Kepler project, the LAMOST-Kepler/K2 Survey aims to collect time-series spectroscopies with medium-resolution on about 55,000 stars distributed on Kepler and K2 campaigns, with higher priority given to the targets with available Kepler photometry. Each of those input targets will be visited about 60 times during the period from September 2018 to June 2023. This project is allocated with one sixth of the entire time within the LAMOST medium-resolution observations.

    From May 2018 to June 2019, a total of thirteen LAMOST-Kepler/K2 Survey footprints have been visited by LAMOST, and obtained about 370,000 high-quality spectra of 28,000 stars. The internal uncertainties for the effective temperature, surface gravity, metallicity and radial velocity are 80 K,0.08 dex, 0.05 dex and 1km/s when the signal to noise ratio equals to 20, respectively, which suggests that the performance of LAMOST medium-resolution spectrographs meet the designed expectation. The external comparisons with GAIA and APOGEE show that LAMOST stellar atmospheric parameters have a good linear relationship, which indicates the quality of LAMOST medium-resolution spectra is reliable.

    The result demonstrated that the medium-resolution spectrographs on LAMOST performed to the designed expectation.

    The LAMOST-Kepler/K2 Survey was launched based on the success of the LAMOST-Kepler project, a low-resolution spectroscopic survey that consecutively performed since 2011.

    Different from LAMOST-Kepler project, the LAMOST-Kepler/K2 Survey aims to collect time-series spectroscopies with medium resolution on about 55,000 stars distributed on Kepler and K2 campaigns, with higher priority given to the targets with available Kepler photometry.

    Each of those input targets will be visited about 60 times during the period from September 2018 to June 2023. This project is allocated with one-sixth of the entire time within the LAMOST medium-resolution observations.

    From May 2018 to June 2019, a total of 13 LAMOST-Kepler/K2 Survey footprints have been visited by LAMOST, and obtained about 370,000 high-quality spectra of 28,000 stars.

    The internal uncertainties for the effective temperature, surface gravity, metallicity and radial velocity were 80 K,0.08 dex, 0.05 dex and 1km/s when the signal to noise ratio equals to 20, respectively, which suggested that the performance of LAMOST medium-resolution spectrographs meet the designed expectation.

    The external comparisons with GAIA and APOGEE showed that LAMOST stellar atmospheric parameters had a good linear relationship, which indicated the quality of LAMOST medium-resolution spectra is reliable.

    ESA (EU)/GAIA satellite .

    SDSS Apache Point Observatory Galactic Evolution Experiment – Apogee

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude2,788 meters (9,147 ft).

    Apache Point Observatory, near Sunspot, New Mexico Altitude 2,788 meters (9,147 ft).

    The LAMOST-Kepler/K2 Survey is the first project dedicated to obtaining time series of spectra by using the LAMOST medium-resolution spectrographs, pointing toward the Kepler/K2 fields. These spectra will be very important for many scientific goals, including the discovery of new binaries or even the brown dwarfs, the study of oscillation dynamics for large-amplitude pulsators and the investigation of the variability of stellar activity.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) (CN) was officially founded in April 2001 through the merger of four observatories, three observing stations and one research center, all under the Chinese Academy of Sciences (CAS).

    NAOC is headquartered in Beijing and has four subordinate units across the country: the Yunnan Observatory (YNAO), the Nanjing Institute of Astronomical Optics and Technology (NIAOT), the Xinjiang Astronomical Observatory (XAO) and the Changchun Observatory.

    The headquarters of NAOC, located in Beijing and formerly known as the Beijing Astronomical Observatory, is simply referred to as NAOC. Established in 1958 and aiming at the forefront of astronomical science, NAOC conducts cutting-edge astronomical studies, operates major national facilities and develops state-of the-art technological innovations. Applying astronomical methods and knowledge to fulfill national interests and needs is also an integral part of the mission of NAOC. NAOC hosts the Center for Astronomical Mega-Science of Chinese Academy of Sciences (CAMS), which is a new initiative to establish a mechanism for reaching consensus in the construction of major facilities, operations and technology developments among the CAS core observatories (NAOC; the Purple Mountain Observatory, PMO; and the Shanghai Astronomical Observatory, SHAO). CAMS will strive for the sharing of financial, personnel resources and technical expertise among the three core observatories of CAS.

    NAOC’s main research involves cosmological large-scale structures, the formation and evolution of galaxies and stars, high-energy astrophysics, solar magnetism and activity, lunar and deep space exploration, and astronomical instrumentation.

    NAOC has seven major research divisions in the areas of optical astronomy, radio astronomy, galaxies and cosmology, space science, solar physics, lunar and deep space exploration, and applications in astronomy. These divisions encompass more than 50 research groups and house the CAS Key Laboratories of Optical Astronomy, Solar Activity, Lunar and Deep-Space Exploration, Space Astronomical Science and Technology, and Computational Astrophysics.

    NAOC also has three major observing stations: Xinglong, for optical and infrared astronomy; Huairou, for solar magnetics; and Miyun, for radio astronomy and satellite data downlinks. NAOC has been deeply involved in the China Lunar Exploration Program, from designing and managing lunar exploration satellite payload systems, to receiving, storing and analyzing the data transmitted by these satellites from space. NAOC also has a GPU super-cluster computing facility with 85 nodes at a peak performance of up to 280 teraflops.

    NAOC also publishes Research in Astronomy and Astrophysics (RAA), a journal catalogued by SCI.

    The Chinese Academy of Sciences (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 4:38 pm on December 21, 2015 Permalink | Reply
    Tags: , , , Spectrographs   

    From SDSS: “Building the APOGEE-2S Spectrograph: Putting Together All the Little Pieces” 

    SDSS Science blog bloc

    Science Blog from the SDSS

    December 21, 2015
    David Whelan

    Building a spectrograph is no mean feat — and an instrument like the APOGEE spectrograph, with high expectations of precision to meet its mighty science goals, takes time and effort. Today we want to share with you some of the many highlights of the ongoing, and exciting, work being done to make the APOGEE-2S spectrograph, the “twin” spectrograph that is going to perform survey operations on the du Pont Telescope at Las Campanas Observatory in Chile.

    Las Campanas Dupont telescope exterior
    Las Campanas Dupont telescope interior
    Las Campanas duPont telescope

    Spectrographs have several key components. The light collected by the telescope from a star is collimated by a great big lens before it strikes the diffraction grating, which splits the light into its constituent colors (it’s a fancy prism). The “split” light then travels through a camera so that it can be refocused onto the infrared array, which records the spectrum of the star.

    With that in mind, here’s a picture of a part of the collimator known as the collimator positioning actuator, which is the little piece of metal seen at the center of the test dewar (the large cylinder). Its role is to precisely position the collimator lens, to ensure precise collimation at all times.

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    Josh Peebles from Johns Hopkins is seen here preparing the collimator positioning actuator inside of a dewar for cryogenic testing. No image credits.

    Next we have some fancy-looking lenses. Because APOGEE works with infrared wavelengths, the lenses have to be made out of substances that are transparent to infrared light, not visible light. As a result, they are actually opaque at visible wavelengths. In the picture below, the lens appears green to us, but this fused silicon lens would be see-through if we had infrared-sensitive eyes.

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    This is one of the APOGEE-2S spectrograph’s lenses (there are six of them in total) up close. It is made of fused silicon, and is transparent to infrared light.

    New England Optical Systems installed these lenses into the camera barrels — the black cylinders shown below — which will be attached to form the spectrograph’s camera (see further below).

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    In November, New England Optical Systems finished installing the lenses into the camera barrel.

    As of just a few days ago, the camera is now fully assembled, and is currently undergoing tests to ensure that it is working to specifications.

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    The spectrograph camera is fully assembled, and undergoing a test called laser unequal path interferometry (LUPI for short).

    This little photojournal makes building a multi-million dollar spectrograph look so neat and tidy! One final picture to disillusion you. Below is Matt Hall, one of the technicians at the University of Virginia assisting with the build. In this picture, he is testing springs that are used to hold some of the lenses in place. It sounds strange that springs are part of a lens system; but because the APOGEE-2S spectrograph is going to be cooled cryogenically, the lenses will all shrink a little. These springs apply pressure to the edges of the lenses so that they stay in place when they shrink.

    This picture illustrates the secret to building instruments like the APOGEE-2S spectrograph: every big piece, like the collimator or camera, is made up of dozens or even hundreds of small, interconnected and interdependent pieces. And each little piece has to be built and tested to ensure that it does its job properly. So here’s to the people, both in Chile and in the U.S., who are currently dedicating their time and effort to build the best spectrograph possible. We look forward to making good use of it!

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    Matt Hall (UVa) is seen here testing the spring constants of individual spring plungers. As with every small part of the build, it is dealt with meticulously and thoroughly so that the completed spectrograph works at the highest level possible.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    After nearly a decade of design and construction, the Sloan Digital Sky Survey saw first light on its giant mosaic camera in 1998 and entered routine operations in 2000. While the collaboration and scope of the SDSS have changed over the years, many of its key principles have stayed fixed: the use of highly efficient instruments and software to enable astronomical surveys of unprecedented scientific reach, a commitment to creating high quality public data sets, and investigations that draw on the full range of expertise in a large international collaboration. The generous support of the Alfred P. Sloan Foundation has been crucial in all phases of the SDSS, alongside support from the Participating Institutions and national funding agencies in the U.S. and other countries.

    The Sloan Digital Sky Survey has created the most detailed three-dimensional maps of the Universe ever made, with deep multi-color images of one third of the sky, and spectra for more than three million astronomical objects.

    In its first five years of operations, the SDSS carried out deep multi-color imaging over 8000 square degrees and measured spectra of more than 700,000 celestial objects. With an ever-growing collaboration, SDSS-II (2005-2008) completed the original survey goals of imaging half the northern sky and mapping the 3-dimensional clustering of one million galaxies and 100,000 quasars. SDSS-II carried out two additional surveys: the Supernova Survey, which discovered and monitored hundreds of supernovae to measure the expansion history of the universe, and the Sloan Extension for Galactic Understanding and Exploration (SEGUE), which extended SDSS imaging towards the plane of the Galaxy and mapped the motions and composition of more than a quarter million Milky Way stars.

    SDSS-III (2008-2014) undertook a major upgrade of the venerable SDSS spectrographs and added two powerful new instruments to execute an interweaved set of four surveys, mapping the clustering of galaxies and intergalactic gas in the distant universe (BOSS), the dynamics and chemical evolution of the Milky Way (SEGUE-2 and APOGEE), and the population of extra-solar giant planets (MARVELS).

    The latest generation of the SDSS (SDSS-IV, 2014-2020) is extending precision cosmological measurements to a critical early phase of cosmic history (eBOSS), expanding its revolutionary infrared spectroscopic survey of the Galaxy in the northern and southern hemispheres (APOGEE-2), and for the first time using the Sloan spectrographs to make spatially resolved maps of individual galaxies (MaNGA).

    This is the “Science blog” of the SDSS. Here you’ll find short descriptions of interesting scientific research and discoveries from the SDSS. We’ll also update on activities of the collaboration in public engagement and other arenas. We’d love to see your comments and questions about what you read here!

    You can explore more on the SDSS Website.

     
  • richardmitnick 8:18 pm on September 17, 2015 Permalink | Reply
    Tags: , , , Spectrographs   

    From ESO: “Spectroscopy” 


    European Southern Observatory

    If signs of life on another planet are ever discovered, they will be found with a spectrograph

    Spectroscopy is one of an astronomer’s favourite tools to help understand the Universe. Planets, stars and galaxies are just too far away to be analysed in a laboratory. Fortunately, very important information about these distant bodies is written in the light we detect with a telescope.

    But the light is not an open book. To be read, light must be split into its different colours (or wavelengths), in the same way that rain droplets disperse the light to form a rainbow. Newton called this rainbow of colours a spectrum, the Latin word for “image”.

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    A prism splits white light into its components: the colours of the rainbow.

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    A natural prism, familiar to everybody

    The first astronomical application of spectroscopy was in the analysis of sunlight by Fraunhofer and Kirchhoff, in the early 19th century. It was expected that the white light emitted from the Sun would produce a clean rainbow when passing through a prism. But, for the very first time, a pattern of dark lines was also noticed. These unexpected lines were the fingerprintsimprinted in the light by the different chemical elements interacting with it and are called absorption lines.

    The beauty of this interaction is that each chemical element or molecule produces a unique signature in the spectrum, a sort of barcode that unequivocally identifies one element from another. By decoding these barcodes, spectroscopy can reveal important properties of any body which emits or absorbs light.

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    The barcode of the Sun. A very long spectrum was chopped in small chunks and then displayed one on top of another.
    Credit: NOAO/AURA/NSF

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    A star emits light across the spectrum — a continuum. When white light goes through a prism, it forms a rainbow, its spectrum. In the same way, as light from a star goes through the gas of a nebula — or even just the atmosphere of the star — specific colours (or wavelengths) are absorbed by the elements contained in the gas, producing dark lines over the continuum. This is an absorption spectrum. The energy that is absorbed by the gas is then re-emitted in all directions, also at the specific colours characteristic of the elements present in the gas, producing bright lines at certain wavelengths; this is known as an emission spectrum.

    Spectrographs are fundamental pieces of astronomical instrumentation and they are far more sophisticated than a prism. Instead of a simple rainbow, the output is a spectrum in which the light is much more dispersed than in a rainbow. The spectra are recorded on a CCD detector and finally saved in computer files for further processing and analysis. The spectrum of a star or any astronomical object not only reveals the presence of certain chemical elements, but also informs about the prevailing physical conditions, such as temperature and density. Spectra can also tell us about motion: by using the Doppler effect, the speed of a star or a galaxy with respect to the Earth can be measured. This effect is used to discover extrasolar planets, and a similar effect allows astronomers to measure the distances to galaxies. Spectra also contain information on the magnetic field present in the object, the composition of the matter and much more.

    Most of the telescopes at ESO’s observatories have spectrographs or have a spectroscopic mode. They cover different ranges of wavelength (from the near-ultraviolet to the mid-infrared) and offer different spectral resolutions (the higher the spectral resolution, the stronger the dispersion of the light, and the smaller the details of the spectrum that can be detected).

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    Illustration of a spectrum taken by X-shooter. This instrument can take simultaneous spectra of an object over a broad range of colours (or wavelengths), from ultraviolet to infrared.

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    Most spectrographs select the light to be split using a slit, which can be long or very short, or even just a small hole. Only that light is sent to the spectrograph (not shown here), and produce a spectrum of that slit.

    Some spectrographs at the Very Large Telescope in Paranal produce high-resolution spectra like UVES and CRIRES; others obtain spectra of many objects at the same time like FLAMES and VIMOS; and a few, like KMOS, MUSE and SINFONI, can even take spectra over their whole field of view (see Integral Field Spectroscopy).

    ESO VLT UVES
    UVES

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    CRIRES

    At the La Silla Observatory, the instruments installed at the New Technology Telescope (NTT), EFOSC2 (and its predecessor EMMI) and SOFI are also spectrographs. But HARPS, installed on the ESO 3.6-metre telescope, is certainly one of the most famous for its leading role in the detection of exoplanets.

    ESO EFOSC2
    EFOSC2

    ESO SOFI
    SOFI

    ESO HARPS
    HARPS

    The next generation of spectrographs, like those planned for the European Extremely Large Telescope (E-ELT), will go beyond anything we can currently achieve. Among the things we cannot do today, astronomers expect to be able to look for possible traces of life in the atmospheres of exoplanets similar to Earth. If signs of life are ever discovered on another planet, it’s most likely that the instrument involved will be a spectrograph.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition
    Visit ESO in Social Media-

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO LaSilla
    LaSilla

    ESO VLT Interferometer
    VLT

    ESO Vista Telescope
    VISTA

    ESO VLT Survey telescope
    VLT Survey Telescope

    ALMA Array
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    ESO E-ELT
    E-ELT

    ESO APEX
    Atacama Pathfinder Experiment (APEX) Telescope

     
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