"A joint project has been proposed by the Chinese and Spanish astronomy communities, to develop a high-resolution, ultra- stable spectrograph for the Gran Telescopio Canarias (GTC) at La Palma. Being expected to conduct precise radial velocity (PRV) measurement with extreme precision of up to 10 cm s−1, the instrument would promote the very high, present interest in the astronomical community to detect and characterize exoplanets. The project successfully passed the conceptual design review (CoDR) in 2019. The instrument is composed of a near-UV band spectrograph (UVS) and a visible band spectrograph (VIS). They provide a spectral resolving power of R ≥100,000 in the visible band (420 nm – 780 nm), and R≥25,000 in the UV band (310 nm – 420 nm). The VIS subsystem will be enclosed in an ultra-stable environment in the Coudé room for the stellar precise radial velocity (PRV) measurements. T he UVS subsystem will be located near the Nasmyth focus to improve the total throughput at the wavelength shorter than 400 nm, to ensure various additional science cases ranging from stellar evolution to the measurement of fundamental constants. This paper gives an overview of the project background, science cases, and technical considerations during the conceptual design phase."
The study of supermassive black hole (SMBH) is one of the most confusing astronomical topics. However, little is known about the co-evolution of SMBH and galaxies, and also the formation process of SMBH. SMBH is considered to be a celestial body on the cosmic scale. As a probe, SMBH plays an irreplaceable key role in the study of the structure and evolution of the universe. The above-mentioned scientific researches requires 10 micro arcsecond astrometry precision. Based on the differential delay interferometry, we plan to develop a prototype long baseline optical interferometry facility to achieve high precision astrometry. The planned prototype facility includes three 500mm siderostats, and the detection waveband covers both near infrared and short wave infrared (J, H). The astrometry precision of the prototype facility is expected to be at the level of ten micro arcseconds.
The non-redundant aperture masking techniques transforms telescope into a Fizeau interferometer by a simple action of placing an aperture mask over the pupil, the limited resolution set by atmospheric fluctuations can be overcome by closure phase techniques to obtain diffraction-limited images. For binary stars, the closure phases can not only eliminate the influence of atmospheric fluctuations on ground-based optical telescope, but also have a functional relationship with contrast and angular separation of binary stars. In this paper, basing on the mathematical model of non-redundant aperture masking detecting binary stars, we carry out the computer simulation and laboratory experiment by using the Golay-6 mask.
The Coronal Solar Magnetism Observatory Large Coronagraph (COSMO-LC) is a 1.5 meter Lyot coronagraph dedicated to measuring magnetic fields and plasma properties in the solar corona. The COSMO-LC will be able to observe coronal emissions lines from 530-1100 nm using a filtergraph instrument. COSMO-LC will have a 1 degree field of view to observe the full solar corona out to 1 solar radius beyond the limb of the sun. This presented challenges due to the large Etendue of the system. The COSMO-LC spatial resolution is 2 arc-seconds per pixel (4k X 4k). The most critical part of the coronagraph is the objective lens that is exposed to direct sunlight that is five orders of magnitude brighter than the corona. Therefore, it is key to the operation of a coronagraph that the objective lens (O1) scatter as little light as possible, on order a few parts per million. The selection of the material and the polish applied to the O1 are critical in reducing scattered light. In this paper we discuss the design of the COSMO-LC and the detailed design of the O1 and other key parts of the COSMO-LC that keep stray light to a minimum. The result is an instrument with stray light below 5 millionths the brightness of the sun 50 arc-seconds from the sun. The COSMO-LC has just had a Preliminary Design Review (PDR) and the PDR design is presented.
ASO-S is a mission proposed for the 25th solar maximum by the Chinese solar community. The scientific objectives are to study the relationships among solar magnetic field, solar flares, and coronal mass ejections (CMEs). ASO-S consists of three payloads: Full-disk Magnetograph (FMG), Lyman-alpha Solar Telescope (LST), and Hard X-ray Imager (HXI), to measure solar magnetic field, to observe CMEs and solar flares, respectively. ASO-S is now under the phase-B studies. This paper makes a brief introduction to the mission.
We have developed a portable solar and stellar adaptive optics (PSSAO) system, which is optimized for solar and stellar high-resolution imaging in the near infrared wavelength range. Our PSSAO features compact physical size, low cost and high performance. The AO software is based on LabVIEW programing and the mechanical and optical components are based on off-the-shelf commercial components, which make a high quality, duplicable and rapid developed AO system possible. In addition, our AO software is flexible, and can be used with different telescopes with or without central obstruction. We discuss our portable AO design philosophy, and present our recent on-site observation results. According to our knowledge, this is the first portable adaptive optics in the world that is able to work for solar and stellar high-resolution imaging with good performances.
This article is focused on the two-level control system of ODL, which are divided into bottom layer control of linear
motor and upper layer control of Piezoelectric Transducer(PZT).This ODL are designed to compensate geometrical
optical path difference, which results from the earth rotation, and other disturbances, with high-accuracy and real time.
Based on the PLC of PMAC controller, the linear motor tracks the trajectory of the simulated optical path difference to
compensate roughly. PZT then compensates the rest error measured by ZLM almost real time. A detailed fulfillment of
this method is shown in the article, and the first result data is produced. The result implies that this method is efficient.
This article offers the reference for the ODL development with the practical high accuracy of compensation.
An optical delay line system for NIAOT Prototype long baseline stellar optical interferometer is being developed. The
delay line system consists of optics part, machine part and control part.
The optics part is a cat's-eye system which includes a paraboloidal mirror and a flat mirror. The flat mirror is placed at
the focus, and is driven by a piezoelectric actuator for real-time compensation of the tracking error. The defocus of the
flat mirror caused by this compensating is considered in optical design; and that the aberration of the optical system
design and the manufacture precision of optical components should not cause the decline in visibility of the fringe is
The machinel part includes precision rails and delay line carriage. The rails require high stability and parallelism. The
cart should be quakeproof when it is moved continuously in the observation process, so the rolling friction drive mode is
selected as the suitable link method between the carriage and the rails.
The control part includes delay line carriage device control and laser metrology system device control. During an
observation, an astrometric model provides a demand cart position and velocity to control computer, the control
computer send them to the device controllers. The metrology system produces tracking error fed back to the cart device
controller via the control system. This feedback servo loop controls the tracking error.
An optical aperture synthesis telescope such as the LBT will suffer from phase errors unless the apertures are aligned to
within a small fraction of a wavelength. A phase diversity wave-front sensor can measure phase errors brought by a
misaligned aperture synthesis telescope. The Phase Diversity is formulated in the context of nonlinear programming
where a metric is developed and then minimized. We here introduce a novel Genetic Algorithms (GAs), evaluate the
different Zernike coefficients to obtain the wave-front error. The results of the computer simulations performed with
simulated data including the effects of noise are shown for the case of random misalignment phase errors on each of
A large Schmitt reflector telescope, Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST), is being
built in China, which has effective aperture of 4 meters and can observe the spectra of as many as 4000 objects
simultaneously. To fit such a large amount of observational objects, the dispersion part is composed of a set of 16
multipurpose fiber-fed double-beam Schmidt spectrographs, of which each has about ten of moveable components realtimely
accommodated and manipulated by a controller. An industrial Ethernet network connects those 16 spectrograph
controllers. The light from stars is fed to the entrance slits of the spectrographs with optical fibers.
In this paper, we mainly introduce the design and realization of our real-time controller for the spectrograph, our design
using the technique of System On Programmable Chip (SOPC) based on Field Programmable Gate Array (FPGA) and
then realizing the control of the spectrographs through NIOSII Soft Core Embedded Processor. We seal the stepper
motor controller as intellectual property (IP) cores and reuse it, greatly simplifying the design process and then
shortening the development time. Under the embedded operating system μC/OS-II, a multi-tasks control program
has been well written to realize the real-time control of the moveable parts of the spectrographs. At present, a number of
such controllers have been applied in the spectrograph of LAMOST.