The Daniel K. Inouye Solar Telescope – Observatory Overview

Abstract

We present an overview of the National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST), its instruments, and support facilities. The 4 m aperture DKIST provides the highest-resolution observations of the Sun ever achieved. The large aperture of DKIST combined with state-of-the-art instrumentation provide the sensitivity to measure the vector magnetic field in the chromosphere and in the faint corona, i.e. for the first time with DKIST we will be able to measure and study the most important free-energy source in the outer solar atmosphere – the coronal magnetic field. Over its operational lifetime DKIST will advance our knowledge of fundamental astronomical processes, including highly dynamic solar eruptions that are at the source of space-weather events that impact our technological society. Design and construction of DKIST took over two decades. DKIST implements a fast (f/2), off-axis Gregorian optical design. The maximum available field-of-view is 5 arcmin. A complex thermal-control system was implemented in order to remove at prime focus the majority of the 13 kW collected by the primary mirror and to keep optical surfaces and structures at ambient temperature, thus avoiding self-induced local seeing. A high-order adaptive-optics system with 1600 actuators corrects atmospheric seeing enabling diffraction limited imaging and spectroscopy. Five instruments, four of which are polarimeters, provide powerful diagnostic capability over a broad wavelength range covering the visible, near-infrared, and mid-infrared spectrum. New polarization-calibration strategies were developed to achieve the stringent polarization accuracy requirement of 5×10−4. Instruments can be combined and operated simultaneously in order to obtain a maximum of observational information. Observing time on DKIST is allocated through an open, merit-based proposal process. DKIST will be operated primarily in “service mode” and is expected to on average produce 3 PB of raw data per year. A newly developed data center located at the NSO Headquarters in Boulder will initially serve fully calibrated data to the international users community. Higher-level data products, such as physical parameters obtained from inversions of spectro-polarimetric data will be added as resources allow.

Polarization modeling and predictions for Daniel K. Inouye Solar Telescope, part 7: preliminary NCSP system calibration and model fitting

“…We refer the reader to recent papers outlining the various capabilities of the first-light instruments. 1,2,2,4,6,8,9 Complex polarization modulation and calibration strategies are required for multi-instrument astronomical systems. 8,9,12,13,32,33 The planned 4-m on-axis European Solar Telescope will also require similar calibration considerations.…”

Magnetohydrodynamic Simulations of Spicular Jet Propagation Applied to Lower Solar Atmosphere Model

“…Here, for the first time in solar jets, the possible presence of internal substructures in these jets are highlighted, which can provide important insights into the generation mechanisms of chromospheric jets (pulse-, reconnection-, convection-, solar global oscillation-, or vortexdriven, etc.). Furthermore, the (simulated) substructures found in these highly localized chromospheric jets may give a new window and impetus to investigate the jet behavior at the highest possible resolution available by using data, e.g., from the Daniel K. Inouye Solar Telescope (DKIST) (Rast et al 2019;Rimmele et al 2020) and, in the future, the upcoming European Solar Telescope (EST) (Collados et al 2010;Jurčák et al 2019;Schlichenmaier et al 2019)…”

Polarization modeling and predictions for DKIST, part 8: calibration polarizer spatial variation impacts

“…We use the normalized form for the polarizer Mueller matrix from Eq. (29) and multiply by the same matrix form for a crossed polarizer with reversed signs in the [0,1] and [1,0] elements. We get the Mueller matrix for crossed polarizers per Eq.…”