Long-term synoptic observations of the Sun in different wavelength regions are essential to understand its secular behavior. Such observations have proven very important for discovery of 11 year solar activity cycle, 22 year magnetic cycle, polar field reversals, Hale’s polarity law, Joy’s law, that helped Babcock and Leighton to propose famous solar dynamo model. In more recent decades, the societal impact of the secular changes in Sun’s output has been felt in terms of solar inputs to terrestrial climate-change and space-weather hazards. Further, it has been realized that to better understand the activity phenomena such as flares and coronal mass ejections (CMEs) one needs synoptic observations in multiple spectral lines to enable tomographic inference of physical parameters. Currently, there are both space and ground based synoptic observatories. However, given the requirements for the long-term stability and reliability of such synoptic datasets, ground-based facilities are more preferable. Also, the ground based observatories are easy to maintain or upgrade while detailed and frequent calibrations are easily possible. The only ground-based facility that currently provides full-disk velocity and magnetic field maps of the Sun around the clock and at good cadence, is the Global Oscillations Network Group (GONG) network of National Solar Observatory (NSO) which is operational since the mid 90s. Due to its aging instrumentation, operating for nearly three decades, and new requirements to obtain multiwavelength observations, a need is felt in the solar community to build a next generation synoptic observatory network. A group of international observatories have come together under the auspices of SOLARNET program, funded by European Union (EU), to carryout a preliminary design study of such a synoptic solar observing facility called “SPRING”, which stands for Solar Physics Research Integrated Network Group. In this article we will present concept of SPRING and the optical design concept of its major instruments.ts.
KEYWORDS: Telescopes, Control systems, Mirrors, Wavefronts, Adaptive optics, Observatories, Control systems design, Buildings, Interfaces, Solar telescopes
The four-meter Advanced Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. Development of a four-meter solar telescope presents many technical challenges (e.g., thermal control of the enclosure, telescope structure and optics). We give a status report of the ATST project (e.g., system design reviews, instrument PDR, Haleakala site environmental impact statement progress) and summarize the design of the major subsystems, including the telescope mount assembly, enclosure, mirror assemblies, wavefront correction, and instrumentation.
The Advanced Solar Technology Telescope (ATST) is a 4-m solar telescope being designed for high spatial, spectral and temporal resolution, as well as IR and low-scattered light observations. The overall limit of performance of the telescope is strongly influenced by the qualities of the site at which it is located. Six sites were tested with a seeing monitor and a sky brightness instrument for 1.5 to 2 years. The sites were Big Bear (California), Haleakala (Hawaii), La Palma (Canary Islands, Spain), Panguitch Lake (Utah), Sacramento Peak (New Mexico), and San Pedro Martir (Baja California, Mexico). In this paper we will describe the methods and results of the site survey, which chose Haleakala as the location of the ATST.
The four-meter Advanced Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. Development of a four-meter solar telescope presents many technical challenges, which include: thermal control of optics and telescope structure; contamination control of the primary mirror to achieve low scattered light levels for coronal observations; control of instrumental polarization to allow accurate and precise polarimetric observations of solar magnetic fields; and high-order solar adaptive optics that uses solar granulation as the wavefront sensing target in order to achieve diffraction limited imaging and spectroscopy. We give a status report of the ATST project focusing on the substantial progress that has been made with the design of the ATST. We summarize the design of the major subsystems, including the enclosure, the primary and secondary mirror assemblies, the coude and Nasmyth focal stations, adaptive optics and instrumentation. The site selection has been successfully concluded and we discuss areas where the site selection impacts the design.
KEYWORDS: Telescopes, Adaptive optics, Optical instrument design, Polarization, Solar telescopes, Polarimetry, Mirrors, Visible radiation, Space telescopes, Control systems design
The Advance Technology Solar Telescope (ATST) has finished its conceptual design stage, submitted a proposal for construction funding and is working towards a system level preliminary design review later this year. The current concept (including integrated adaptive optics and instrumentation) will be reviewed with concentration on solutions to the unique engineering challenges for a four meter solar telescope that have been previously presented. The overall status will be given with a concentration on near term milestones and impact on final completion targeted in 2012.
The location of the Advanced Technology Solar Telescope (ATST) is a critical factor in the overall performance of the telescope. We have developed a set of instrumentation to measure daytime seeing, sky brightness, cloud cover, water vapor, dust levels, and weather. The instruments have been located at six sites for periods of one to two years. Here we describe the sites and instrumentation, discuss the data reduction, and present some preliminary results. We demonstrate that it is possible to estimate seeing as a function of height near the ground with an array of scintillometers, and that there is a distinct qualitative difference in daytime seeing between sites with or without a nearby lake.
Frank Hill, Richard Bogart, Alisdair Davey, George Dimitoglou, Joseph Gurman, Joseph Hourcle, Petrus Martens, Igor Suarez-Sola, Karen Tian, Steven Wampler, Keiji Yoshimura
KEYWORDS: Observatories, Human-machine interfaces, Data archive systems, Solar processes, Data modeling, Physics, Distributed computing, Information technology, Data mining, Data centers
The Virtual Solar Observatory (VSO) is a bottom-up grassroots approach to the development of a distributed data system for use by the solar physics community. The beta testing version of the VSO was released in December 2003. Since then it has been tested by approximately 50 solar physicists. In this paper we will present the status of the project, a summary of the community's experience with the tool, and an overview of the lessons learned.
The 4m ATST will be the most powerful solar telescope in the world, providing a unique scientific tool to study the Sun and other astronomical objects. The design and development phase for the Advance Technology Solar Telescope (ATST) is progressing. The conceptual design review (CoDR) for the ATST is scheduled for August 2003. We present a brief description of the science requirements of ATST, and remind the reader of some of the technical challenges of building a 4-m solar telescope. We will discuss some of the design strategies that will allow us to achieve the required performance specifications, present conceptual designs for the ATST, and summarize the results of trades we have made on our path to the CoDR. The thermal impacts to local, self-induced seeing with respect to some of our system level trades that have been completed will be discussed.
High-resolution studies of the Sun's magnetic fields are needed for a better understanding of solar magnetic fields and the fundamental processes responsible for solar variability. The generation of magnetic fields through dynamo processes, the amplification of fields through the interaction with plasma flows, and the destruction of fields are still poorly understood. There is still incomplete insight as to what physical mechanisms are responsible for heating the corona, what causes variations in the radiative output of the Sun, and what mechanisms trigger flares and coronal mass ejections. Progress in answering these critical questions requires study of the interaction of the magnetic field and convection with a resolution sufficient to observe scales fundamental to these processes.
The 4m aperture Advanced Technology Solar Telescope (ATST) will be a unique scientific tool, with excellent angular resolution, a large wavelength range, and low scattered light. With its integrated adaptive optics, the ATST will achieve a spatial resolution nearly 10 times better than any existing solar telescope. Building a large aperture telescope for viewing the sun presents many challenges, some of the more difficult being
Heat control and rejection
Contamination and scattered light control
Control of telescope and instrument polarization
Site selection
This talk will present a short summary of the scientific questions driving the ATST design, the design challenges faced by the ATST, and the current status of the developing design and siting considerations
We investigate a number of ideas about the effect of various topographical and climtatological factors on daytime seeing. Using the results of the CalTech site survey in southern California, we confirm that the presence of lakes and wind channels are beneficial for solar observing conditions. We do not find that proximity to the ocean is of benefit but is instead detrimental to seeing in the CalTech sample possibly due to the influence of the Los Angeles metropolitan area. We also study the effect of tree removal on the seeing at Sacramento Peak Observatory, and find that removing trees improved the average seeing by 25%. The effects of these and other factors will be further investigated with the ATST site survey.
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 high-resolution 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.
Frank Hill, Andre Csillaghy, Robert Bentley, Jean Aboudarham, Ester Antonucci, Anthony Finkelstein, Luigi Ciminiera, Joseph Gurman, Isabelle Scholl, Dave Pike, Valentin Zharkova
KEYWORDS: Observatories, Data modeling, Solar processes, Data archive systems, Human-machine interfaces, Satellites, Interfaces, Earth observing sensors, Chemical elements, Applied sciences
The European Grid of Solar Observations (EGSO) is a project to develop a virtual observatory for the solar physics community. Like in all such projects, a vital component is a schema that adequately describes the data in the distributed data sets. Here, we discuss the schema in general terms, and present a draft example of a portion of a possible XML schema.
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