Dr. Liang Wang Profile

Dr. Liang Wang

at Nanjing Institute of Astro. Optics and Technology

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Author

Publications (9)

Proceedings Article | 13 September 2024 Paper

Hough transform-based correction method for CCD external interference of AST3-II telescope

Jingjian Chen, Liang Wang, Jie Zheng, Xiaoyan Li, Zhengyang Li

Proceedings Volume 13254, 132541W (2024) https://doi.org/10.1117/12.3039106

KEYWORDS: Charge-coupled devices, Electromagnetic interference, Telescopes, Hough transforms, Astronomy, Astronomical imaging, Quantum reading, Image processing, Astronomical telescopes, Stars

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Proceedings Article | 9 September 2019 Paper

First results of the 4-fiber upgrade of the high-resolution comb calibrated spectrograph FOCES

Hanna Kellermann, Liang Wang, Vanessa Fahrenschon, Frank Grupp, Ulrich Hopp, Ralf Bender

Proceedings Volume 11117, 111171O (2019) https://doi.org/10.1117/12.2529283

KEYWORDS: Calibration, Spectrographs, Spectral calibration, Observatories, Frequency combs, Optical fibers, CCD cameras, Multimode fibers

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Proceedings Article | 12 September 2017 Paper

Line profile analysis of the laser frequency comb in FOCES

Liang Wang, Frank Grupp, Hanna Kellermann, Ulrich Hopp, Ralf Bender

Proceedings Volume 10400, 104001V (2017) https://doi.org/10.1117/12.2273706

KEYWORDS: Charge-coupled devices, Frequency combs, Spectrographs, Telescopes, Signal to noise ratio, Observatories, Laser optics, Space telescopes, Calibration, Mode locking

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Proceedings Article | 9 August 2016 Paper

Multi-fiber coupling through a miniature lens system into the FOCES spectrograph

Hanna Kellermann, Frank Grupp, Anna Brucalassi, Liang Wang, Nils Baisert, Florian Lang-Bardl, Ulrich Hopp, Ralf Bender

Proceedings Volume 9908, 990863 (2016) https://doi.org/10.1117/12.2231389

KEYWORDS: Observatories, Spectrographs, Calibration, Telescopes, Zemax, Velocity measurements, Frequency combs, Lens design, Image quality, Microscopes

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Proceedings Article | 9 August 2016 Paper

Stability of the FOCES spectrograph using an astro-frequency comb as calibrator

Anna Brucalassi, Frank Grupp, Hanna Kellermann, Liang Wang, Florian Lang-Bardl, Nils Baisert, Shao Ming Hu, Ulrich Hopp, Ralf Bender

Proceedings Volume 9908, 99085W (2016) https://doi.org/10.1117/12.2231395

KEYWORDS: Calibration, Spectrographs, Observatories, Frequency combs, Frequency combs, Telescopes, Laser stabilization, Charge-coupled devices, Precision calibration, Astronomical telescopes, Astronomy

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Proceedings Article | 9 August 2016 Paper

A new generation of spectral extraction and analysis package for Fibre Optics Cassegrain Echelle Spectrograph (FOCES)

Liang Wang, Frank Grupp, Hanna Kellermann, Anna Brucalassi, Jörg Schlichter, Ulrich Hopp, Ralf Bender

Proceedings Volume 9913, 99133O (2016) https://doi.org/10.1117/12.2231393

KEYWORDS: Spectrographs, Fiber optics, Telescopes, Observatories, Fiber optics, Telescopes, Charge-coupled devices, Calibration, CCD image sensors, Sensors, Spectral calibration, Lamps

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Proceedings Article | 28 July 2014 Paper

Study on a multi-delay spectral interferometry for stellar radial velocity measurement

Kai Zhang, Haijiao Jiang, Jin Tang, Hangxin Ji, Yongtian Zhu, Liang Wang

Proceedings Volume 9147, 914757 (2014) https://doi.org/10.1117/12.2055562

KEYWORDS: Interferometry, Interferometers, Spectrographs, Velocity measurements, Calibration, Doppler effect, Astronomy, Telescopes, Astronomical imaging, Optical interferometry

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High accuracy radial velocity measurement isn’t only one of the most important methods for detecting earth-like Exoplanets, but also one of the main developing fields of astronomical observation technologies in future. Externally dispersed interferometry (EDI) generates a kind of particular interference spectrum through combining a fixed-delay interferometer with a medium-resolution spectrograph. It effectively enhances radial velocity measuring accuracy by several times. Another further study on multi-delay interferometry was gradually developed after observation success with only a fixed-delay, and its relative instrumentation makes more impressive performance in near Infrared band. Multi-delay is capable of giving wider coverage from low to high frequency in Fourier field so that gives a higher accuracy in radial velocity measurement. To study on this new technology and verify its feasibility at Guo Shoujing telescope (LAMOST), an experimental instrumentation with single fixed-delay named MESSI has been built and tested at our lab. Another experimental study on multi-delay spectral interferometry given here is being done as well. Basically, this multi-delay experimental system is designed in according to the similar instrument named TEDI at Palomar observatory and the preliminary test result of MESSI. Due to existence of LAMOST spectrograph at lab, a multi-delay interferometer design actually dominates our work. It’s generally composed of three parts, respectively science optics, phase-stabilizing optics and delay-calibrating optics. To switch different fixed delays smoothly during observation, the delay-calibrating optics is possibly useful to get high repeatability during switching motion through polychromatic interferometry. Although this metrology is based on white light interferometry in theory, it’s different that integrates all of interference signals independently obtained by different monochromatic light in order to avoid dispersion error caused by broad band in big optical path difference (OPD).

Proceedings Article | 24 July 2014 Paper

Test of multi-object exoplanet search spectral interferometer

Kai Zhang, Liang Wang, Haijiao Jiang, Yongtian Zhu, Yonghui Hou, Songxin Dai, Jin Tang, Zhen Tang, Yizhong Zeng, Yi Chen, Lei Wang, Zhongwen Hu

Proceedings Volume 9147, 914758 (2014) https://doi.org/10.1117/12.2055566

KEYWORDS: Spectrographs, Interferometers, Astronomical imaging, Telescopes, Optical fibers, Astronomy, Exoplanetary science, Exoplanets, Iodine cells, Spectral resolution

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Exoplanet detection, a highlight in the current astronomy, will be part of puzzle in astronomical and astrophysical future, which contains dark energy, dark matter, early universe, black hole, galactic evolution and so on. At present, most of the detected Exoplanets are confirmed through methods of radial velocity and transit. Guo shoujing Telescope well known as LAMOST is an advanced multi-object spectral survey telescope equipped with 4000 fibers and 16 low resolution fiber spectrographs. To explore its potential in different astronomical activities, a new radial velocity method named Externally Dispersed Interferometry (EDI) is applied to serve Exoplanet detection through combining a fixed-delay interferometer with the existing spectrograph in medium spectral resolution mode (R=5,000-10,000). This new technology has an impressive feature to enhance radial velocity measuring accuracy of the existing spectrograph through installing a fixed-delay interferometer in front of spectrograph. This way produces an interference spectrum with higher sensitivity to Doppler Effect by interference phase and fixed delay. This relative system named Multi-object Exoplanet Search Spectral Interferometer (MESSI) is composed of a few parts, including a pair of multi-fiber coupling sockets, a remote control iodine subsystem, a multi-object fixed delay interferometer and the existing spectrograph. It covers from 500 to 550 nm and simultaneously observes up to 21 stars. Even if it’s an experimental instrument at present, it’s still well demonstrated in paper that how MESSI does explore an effective way to build its own system under the existing condition of LAMOST and get its expected performance for multi-object Exoplanet detection, especially instrument stability and its special data reduction. As a result of test at lab, inside temperature of its instrumental chamber is stable in a range of ±0.5degree Celsius within 12 hours, and the direct instrumental stability without further observation correction is equivalent to be ±50m/s every 20mins.

Proceedings Article | 26 September 2013 Paper

Pressure and temperature stabilization of an existing Échelle spectrograph IV

Anna Brucalassi, Frank Grupp, Florian Lang, Liang Wang, Christian Franik, Hanna Kellerm, Shao Ming Hu, Ulrich Hopp, Ralf Bender

Proceedings Volume 8864, 88641H (2013) https://doi.org/10.1117/12.2023274

KEYWORDS: Charge-coupled devices, Spectrographs, Temperature metrology, Observatories, Telescopes, Environmental sensing, Spectroscopy, Exoplanets, Photovoltaics, Motion analysis

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Showing 5 of 9 publications

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