Technical challenges of the Advanced Technology Solar Telescope

Abstract

The 4m Advance Technology Solar Telescope (ATST) will be the most powerful solar telescope in the world, providing a unique scientific tool to study the Sun and possibly other astronomical objects, such as solar system planets. We briefly summarize the science drivers and observational requirements of ATST. The main focus of this paper is on the many technical challenges involved in designing a large aperture solar telescope. The ATST project has entered the design and development phase. Development of a 4-m solar telescope presents many technical challenges. Most existing highresolution solar telescopes are designed as vacuum telescopes to avoid internal seeing caused by the solar heat load. The large aperture drives the ATST to an open-air design, similar to night-time telescope designs, and makes thermal control of optics and telescope structure a paramount consideration. A heat stop must reject most of the energy (13 kW) at prime focus without introducing internal seeing. To achieve diffraction-limited observations at visible and infrared wavelengths, ATST will have a high order (order 1000 DoF) adaptive optics system using solar granulation as the wavefront sensing target. Coronal observations require occulting in prime focus, a Lyot stop and contamination control of the primary. An initial set of instruments will be designed as integral part of the telescope. First telescope design and instrument concepts will be presented.

The Daniel K. Inouye Solar Telescope – Observatory Overview

“…The scientific and technical drivers for the off-axis design are discussed by Rimmele et al (2003a) and are briefly summarized as follows. The unobstructed aperture provides the full 12.56 m 2 collecting area and is free from the diffraction effects of the secondary Figure 3 Optical design of DKIST.…”

“…the site characteristics needed to support both the high-resolution and the coronal science objectives. Conceptual, preliminary, and final design phases and reviews were conducted between 2003 and 2009 Rimmele et al, 2003aRimmele et al, ,b, 2005Keil et al, , 2004Oschmann et al, 2004;Wagner et al, 2006;Rimmele, Keil, and Wagner, 2008;Keil, Rimmele, and Wagner, 2010). Design and development of first-light instrumentation progressed simultaneously (Rimmele et al, 2004;Elmore et al, 2014).…”

Advanced Technology Solar Telescope: a progress report

“…The scientific case for ATST has been previously presented 1 and leads to a versatile solution to support diffraction-limited observing at visible and near-and far-infrared wavelengths, and coronal observations near the limb of the sun. The ATST team has made substantial progress in several critical areas.…”

Advanced Technology Solar Telescope optical design

“…The scientific case for ATST has been previously presented 1 and has led to a versatile observatory design 2 supporting diffraction-limited observing at visible through far infrared wavelengths, as well as coronal observations near the limb of the sun. A cutaway view of the observatory is shown in Figure 1.…”