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

Abstract

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.

Modified Method to Detect the Turbulent Layers in the Atmospheric Boundary Layer for the Large Solar Vacuum Telescope

“…where i, j-indices of the subapertures, t-time, s [1] i,j -local slopes of the wavefront on the subaperture i, j of the first Shack-Hartmann wavefront sensor (1), s [2] i+δi,j+δjlocal slopes of the wavefront on the subaperture i + δi, j + δj of the second Shack-Hartmann wavefront sensor (2), O(δi, δj)-the number of crossed subapertures; (v) The turbulence characteristics are estimated using cross-correlation functions and autocovariance function; (vi) Recovering the profiles of turbulent characteristics up to the maximum height is determined by the geometry of light beams from spaced light sources. Heights of crossing beams is estimated using relation (3) [15]:…”

“…The paper is aimed at the development of the method to detect the turbulence layers. This is important for the study of the structure of optical turbulence at the sites of the Large Solar Vacuum Telescope of the Baikal Astrophysical Observatory as well as Sayan Solar Observatory [1,2].…”

Application of Neural Networks to Estimation and Prediction of Seeing at the Large Solar Telescope Site

“…In Russia, the Large Solar Telescope (LST-3) with a mirror diameter of 3 m (  ¢  51 37 18 N,  ¢  100 55 07 E) is being designed (Grigoryev et al 2020). Together with the EST and DKIST telescopes (Sánchez-Capuchino et al 2010;Rimmele et al 2020), the LST-3 will be one of the largest solar telescopes in the world.…”

The Daniel K. Inouye Solar Telescope – Observatory Overview

“…When operated in coordination, DKIST and EST will provide extended temporal coverage that would, for example, enable tracking of an active region in order to study its evolution and enhance the probability to capture observations of flares. Other projects include the Russian 3 m-aperture Large Solar Telescope planned to be located in the Sayan Solar Observatory at an altitude of more than 2000 m (Grigoryev et al, 2020), India's National Large Solar Telescope with aperture 2.5 m (Hasan, 2012), and the Chinese Giant Solar Telescope with a planned aperture of 8 m (Deng et al, 2016). It is conceivable that a network of largeaperture, ground-based solar telescopes could eventually be implemented and provide close to 24 hour temporal coverage of observations of the highest resolution.…”