Project of the Large Solar Telescope with mirror 3 m in diameter

One of the most important problems of modern solar physics is the observation of the small-scale structure of the solar atmosphere at various heights (including the chromosphere and corona) in different spectral lines. Such observations can be made only with large solar telescopes whose main mirror has a diameter of at least 3 m. Currently, several large solar telescopes are under construction or development in the world. In 2013 in Russia, the work began on the development of a national large solar telescope with a mirror 3 m in diameter (LST-3), which is a part (subproject) of the National Heliogeophysical Complex of the Russian Academy of Sciences. The telescope is planned to be located in the Sayan Solar Observatory at an altitude of more than 2000 m. The choice was made in favor of the classic axisymmetric Gregory optical layout on an alt-azimuth mount. The scientific equipment of LST-3 will consist of several systems of narrow-band tunable filters and spectrographs for various wave ranges. The equipment will be placed both in the main coude focus on a rotating platform and in the Nasmyth focus. To achieve a diffraction resolution, high-order adaptive optics (AO) will be used. It is assumed that with a certain modification of the optical configuration, LST-3 will work as a 0.7 m mirror coronograph in near infrared lines and can also be used for observing astrophysical objects in the nighttime.

Download Full-text

Atomic physics and solar polarimetry

Canadian Journal of Physics ◽

10.1139/cjp-2016-0836 ◽

2017 ◽

Vol 95 (9) ◽

pp. 847-854 ◽

Cited By ~ 4

Author(s):

P.G. Judge

Keyword(s):

Adaptive Optics ◽

Atomic Physics ◽

Solar Physics ◽

Polarized Light ◽

Initial Study ◽

Spectral Lines ◽

Calibration Data ◽

Science Data ◽

On Line ◽

Singly Charged

Major outstanding problems in solar physics relate to solar magnetism. Spectropolarimetry offers the best, and sometimes only, method of obtaining accurate measurements of the Sun’s magnetic field. New 1.5–2 m class telescopes with adaptive optics have come on line, and the Daniel K. Inouye 4 m Solar Telescope (DKIST) will begin observing in 2019. The calibration of polarized light entering such a large and polarizing ground-based telescope represents difficult challenges. This paper explores how special polarization properties of particular atomic transitions may provide calibration data, augmenting or even avoiding time-consuming calibration observations, as well as science data. This initial study concludes that solar spectral lines exist with special polarization properties, allowing the telescope calibration to be determined. The Sun’s visible and infrared spectrum is dominated by lines of neutral atoms and singly charged ions of iron and other complex atoms. Both solar and atomic physics should jointly benefit from telescopic advances, as observers explore regimes of broader wavelength ranges, and higher spatial resolutions and polarimetric sensitivities, than they have reached in the past. Further work is in progress to identify particular transitions of practical use to aid in calibrations.

Download Full-text

Low-order adaptive optics for the meter aperture solar telescope of Udaipur Solar Observatory

10.1117/12.509230 ◽

2004 ◽

Author(s):

Rengaswamy Sridharan ◽

A. R. Bayanna

Keyword(s):

Adaptive Optics ◽

Solar Observatory ◽

Solar Telescope ◽

Low Order

Download Full-text

The potential of many-line inversions of photospheric spectropolarimetric data in the visible and near UV

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833379 ◽

2019 ◽

Vol 622 ◽

pp. A36 ◽

Cited By ~ 6

Author(s):

T. L. Riethmüller ◽

S. K. Solanki

Keyword(s):

Wavelength Range ◽

Solar Physics ◽

Solar Observatory ◽

Spectral Lines ◽

Resolving Power ◽

Short Wavelength Range ◽

Photon Noise ◽

Infrared Spectral ◽

The Many

Our knowledge of the lower solar atmosphere is mainly obtained from spectropolarimetric observations, which are often carried out in the red or infrared spectral range and almost always cover only a single or a few spectral lines. Here we compare the quality of Stokes inversions of only a few spectral lines with many-line inversions. In connection with this, we have also investigated the feasibility of spectropolarimetry in the short-wavelength range, 3000 Å−4300 Å, where the line density but also the photon noise are considerably higher than in the red, so that many-line inversions could be particularly attractive in that wavelength range. This is also timely because this wavelength range will be the focus of a new spectropolarimeter in the third science flight of the balloon-borne solar observatory SUNRISE. For an ensemble of state-of-the-art magneto-hydrodynamical atmospheres we synthesize exemplarily spectral regions around 3140 Å (containing 371 identified spectral lines), around 4080 Å (328 lines), and around 6302 Å (110 lines). The spectral coverage is chosen such that at a spectral resolving power of 150 000 the spectra can be recorded by a 2K × 2K detector. The synthetic Stokes profiles are degraded with a typical photon noise and afterward inverted. The atmospheric parameters of the inversion of noisy profiles are compared with the inversion of noise-free spectra. We find that significantly more information can be obtained from many-line inversions than from a traditionally used inversion of only a few spectral lines. We further find that information on the upper photosphere can be significantly more reliably obtained at short wavelengths. In the mid and lower photosphere, the many-line approach at 4080 Å provides equally good results as the many-line approach at 6302 Å for the magnetic field strength and the line-of-sight (LOS) velocity, while the temperature determination is even more precise by a factor of three. We conclude from our results that many-line spectropolarimetry should be the preferred option in the future, and in particular at short wavelengths it offers a high potential in solar physics.

Download Full-text

Two-telescope-based solar seeing profile measurement simulation

Research in Astronomy and Astrophysics ◽

10.1088/1674-4527/21/12/298 ◽

2022 ◽

Vol 21 (12) ◽

pp. 298

Author(s):

Zi-Yue Wang ◽

De-Qing Ren ◽

Raffi Saadetian

Keyword(s):

Numerical Simulations ◽

Atmospheric Turbulence ◽

Adaptive Optics ◽

Solar Observatory ◽

Performance Estimation ◽

Image Motion ◽

Profile Measurement ◽

Solar Telescope ◽

National Solar Observatory ◽

Bear Lake

Abstract Measurements of the daytime seeing profile of the atmospheric turbulence are crucial for evaluating a solar astronomical site so that research on the profile of the atmospheric turbulence as a function of altitude C n 2 ( h n ) becomes more and more critical for performance estimation and optimization of future adaptive optics (AO) including the multi-conjugate adaptive optics (MCAO) systems. Recently, the S-DIMM+ method has been successfully used to measure daytime turbulence profiles above the New Solar Telescope (NST) on Big Bear Lake. However, such techniques are limited by the requirement of using a large solar telescope which is not realistic for a new potential astronomical site. Meanwhile, the A-MASP (advanced multiple-aperture seeing profiler) method is more portable and has been proved that can reliably retrieve the seeing profile up to 16 km with the Dunn Solar Telescope (DST) on the National Solar Observatory (Townson, Kellerer et al.). But the turbulence of the ground layer is calculated by combining A-MASP and S-DIMM+ (Solar Differential Image Motion Monitor+) due to the limitation of the two-individual-telescopes structure. To solve these problems, we introduce the two-telescope seeing profiler (TTSP) which consists of two portable individual telescopes. Numerical simulations have been conducted to evaluate the performance of TTSP. We find our TTSP can effectively retrieve seeing profiles of four turbulence layers with a relative error of less than 4% and is dependable for actual seeing measurement.

Download Full-text

Second generation solar adaptive optics for 1-m New Vacuum Solar Telescope at the Fuxian Solar Observatory

Chinese Optics Letters ◽

10.3788/col201513.120101 ◽

2015 ◽

Vol 13 (12) ◽

pp. 120101-120103 ◽

Cited By ~ 6

Author(s):

Changhui Rao Changhui Rao ◽

Lei Zhu Lei Zhu ◽

Xuejun Rao Xuejun Rao ◽

Lanqiang Zhang Lanqiang Zhang ◽

Hua Bao Hua Bao ◽

...

Keyword(s):

Adaptive Optics ◽

Second Generation ◽

Solar Observatory ◽

Solar Telescope

Download Full-text

An updated 37-element low-order solar adaptive optics system for 1-m new vacuum solar telescope at Full-Shine Lake Solar Observatory

10.1117/12.924338 ◽

2012 ◽

Cited By ~ 2

Author(s):

Changhui Rao ◽

Lei Zhu ◽

Naiting Gu ◽

Xuejun Rao ◽

Lanqiang Zhang ◽

...

Keyword(s):

Adaptive Optics ◽

Solar Observatory ◽

Solar Telescope ◽

Adaptive Optics System ◽

Low Order

Download Full-text

Scientific Programmes with India's National Large Solar Telescope and their contribution to Prominence Research

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313011198 ◽

2013 ◽

Vol 8 (S300) ◽

pp. 355-361

Author(s):

S. S. Hasan

Keyword(s):

High Resolution ◽

Adaptive Optics ◽

High Spatial Resolution ◽

Optical Design ◽

Primary Objective ◽

Spectral Lines ◽

Solar Telescope ◽

Optical Elements ◽

Scientific Questions ◽

Adaptive Optics System

AbstractThe primary objective of the 2-m National Large Solar Telescope (NLST) is to study the solar atmosphere with high spatial and spectral resolution. With an innovative optical design, NLST is an on-axis Gregorian telescope with a low number of optical elements and a high throughput. In addition, it is equipped with a high order adaptive optics system to produce close to diffraction limited performance.NLST will address a large number of scientific questions with a focus on high resolution observations. With NLST, high spatial resolution observations of prominences will be possible in multiple spectral lines. Studies of magnetic fields, filament eruptions as a whole, and the dynamics of filaments on fine scales using high resolution observations will be some of the major areas of focus.

Download Full-text

ASTROCLIMATIC STATISTICS AT THE SAYAN SOLAR OBSERVATORY

Solnechno-Zemnaya Fizika ◽

10.12737/szf-61202012 ◽

2020 ◽

Vol 6 (1) ◽

pp. 126-133

Author(s):

Artem Shikhovtsev ◽

Pavel Kovadlo ◽

Aleksandr Kiselev

Keyword(s):

Adaptive Optics ◽

Solar Observatory ◽

Line Of Sight ◽

Solar Telescope ◽

Vertical Profiles ◽

Minimum Level ◽

Optical Turbulence ◽

Low Intensity ◽

Spatial Features ◽

Adaptive Optics System

The paper analyzes meteorological and optical characteristics of the atmosphere at the Sayan Solar Observatory (SSO) and the future 3 m Large Solar Telescope (LST-3). We examine spatial features of changes in astroclimatic characteristics for the Sayan Solar Observatory and Baikal Astrophysical Observatory (BAO). We have obtained a vertical profile of the structural characteristic of air refractive index fluctuations for a low intensity optical turbulence along the line of sight. This profile is an important result because it will allow us to adjust the adaptive optics system of LST-3 to the best astroclimatic conditions when the correction efficiency is maximal. In order to analyze vertical profiles of optical turbulence characteristics and to assess the contribution of individual atmospheric layers to the isoplanatic angle for a minimum level of total turbulence, we give recommendations for the design of multi-conjugated adaptive optics in general and for LST-3 in particular.

Download Full-text