New telescopes in China

This paper covers the main aspects of three new optical telescopes: a 1.26 m aperture one for use in the infrared, a 1.56 m aperture one for astrometry, and a 2.16 m reflector for general astrophysical work. It also briefly mentions the 13.7 m telescope designed for the mm wavelength band, the first VLBI in China and the meter wavelength aperture synthesis telescope. All these telescopes, optical and radio, are now being built in China.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

New designs of survey telescopes

The immediate goal of modern observational astronomy is to monitor continuously the position and brightness of all objects in the sky brighter than ∼24th magnitude. This review describes wide‐field telescopes designed for this task – both existing and planned. Many systems are described for the first time (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

New aspects for new generation telescopes

A selection of future observing facilities relevant to galaxy evolution science covering the wavelength range from X-rays to the radio regime are summarized. Scientific aspects that can be investigated with these next generation telescopes are briefly discussed. While prospects look bright for highly advanced and innovative future facilities, it will be important to ensure that human resources in observational astronomy and theory – both in terms of expertise, funding, and available positions – are keeping pace with the technological developments. This revised version was published online in August 2006 with corrections to the Cover Date.     

New challenges for adaptive optics: extremely large telescopes

The performance of an adaptive optics (AO) system on a 100-m diameter ground-based telescope working in the visible range of the spectrum is computed using an analytical approach. The target Strehl ratio of 60 per cent is achieved at 0.5 μm with a limiting magnitude of the AO guide source near R   magnitude~10, at the cost of an extremely low sky coverage. To alleviate this problem, the concept of tomographic wavefront sensing in a wider field of view using either natural guide stars (NGS) or laser guide stars (LGS) is investigated. These methods use three or four reference sources and up to three deformable mirrors, which increase up to 8-fold the corrected field size (up to 60 arcsec at 0.5 μm). Operation with multiple NGS is limited to the infrared (in the J band this approach yields a sky coverage of 50 per cent with a Strehl ratio of 0.2). The option of open-loop wavefront correction in the visible using several bright NGS is discussed. The LGS approach involves the use of a faint ( R ~22) NGS for low-order correction, which results in a sky coverage of 40 per cent at the Galactic poles in the visible.     

Gamma-ray telescopes

The last half-century has seen dramatic developments in γ?ray telescopes, from their initial conception and development through to their blossoming into full maturity as a potent research tool in astronomy. Gamma-ray telescopes are leading research in diverse areas such as γ?ray bursts, blazars, Galactic transients, and the Galactic distribution of ²⁶Al.     

New Stars and telescopes: Nova research in the last four centuries

This article gives a brief overview of 400 years of research in the field of novae and related stars. Important objects, first applications of various observing techniques, and early ideas of the interpretation of phenomena are listed. Also, the historical evolution of the classification of novae and related stars (supernovae, dwarf novae), as well as their use as distance indicators is discussed (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Robotic telescopes and networks: New tools for education and science

Nowadays many telescopes around the world are automated and some networks of robotic telescopes are active or planned. Such equipment could be used for thetraining of students and for science in the Universities of DCs and of newastronomical countries, by sending them observational data via Internetor through remotely controlled telescope. It seems that it is thetime to open up for discussion with UN and ESA organizations and also withIAU, how to implement links between robotic telescopes and suchUniversities applying for collaborations. Many scientific fields couldthus be accessible to them, for example on stellar variability, near-earthobject follow-up, -ray burst counterpart tracking, and so on.     

New possibilities of non-eclipse observations of the solar K-corona with liquid-mirror telescopes

Experimental and methodical possibilities of modern observations of the solar K-corona have been analyzed. It is shown that for obtaining information on matter distribution and dynamics in the internal solar corona, it is necessary to measure both its polarization component and its total radiation in the continuum. In order to reduce the atmospheric and instrumental background, the employment of K-coronameters with an apodized liquid mirror is proposed. Such coronameters should operate in the near infrared range and be installed at a latitude zone where the Sun can be observed in the zenith.     

Large-scale diffractive X-ray telescopes

Capabilities of large-scale diffractive X-ray telescopes are discussed. Based on purely transmissive optics, an angular resolution of at least 10⁻³ arcsec will be achieved using detection techniques with spectral selectivities in the sub-eV range for short focal distances of few 10² km. We use stepped versions of Fresnel apertures made of plastic foils, divided into optically independent segments by two alternative schemes. It is shown that point source sensitivities near 10³ cm² keV require lens diameters up to 30 m. Like monochromatic objectives, properly shaped dual- or multiband telescopes may be tuned over several keV. Such configurations are made of partial Fresnel lenses with coinciding focal distances and similar spot sizes and compete well with single-band analogues.     

Cosmology and large telescopes

Assuming a large collecting area, a good angular resolution and a large field of view expected for the Japanese National Large Telescope (JNLT), we demonstrate that JNLT will provide a useful means of studying cosmological objects of interest. Among them I discuss how cosmological parameters and evolutionary effects can be obtained from redshift-magnitude relations, galaxy counts, distant supernovae, quasar properties, and large-scale structures. An advantage of near infrared observations is emphasized.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988.     

High resolution solar telescopes

The advantages and disadvantages of the configurations for high resolution solar telescopes are discussed within two broad groups: those with steerable mountings and those with fixed mountings. We then consider simple optical tests, stabilization of the internal optical path, windows, vibration, guiding and alignment systems, improving the observations, and solutions for large-aperture telescopes for Stokes polarimetry observations. This review does not address all the problems. It is not a compendium of solar telescopes, nor does it include any discussion of focal-plane instrumentation.Operated by the Association of Universities for Research in Astronomy. Inc., under contract with the National Science Foundation.     

History of solar telescopes

Solar observations have been done with telescopes since their invention—already Galileo looked at the Sun. Despite the Sun’s unusual brightness, telescopes which specialize in solar observations are fairly recent, dating from the late nineteenth century onwards. Today, many solar telescopes have rather little in common with nighttime telescopes. They are adapted to high light flux, a limited range of declination, and to the specifications of solar spectrographs and polarimeters. This paper presents the history of the modern optical solar telescope on the ground and in space, the accompanying evolution of scientific capabilities, and a brief outlook into the future.     

Adaptive optics for large telescopes

The performance of large telescopes is determined both by their angular resolution and by their collection area. It is, therefore, important to achieve as high an angular resolution as possible by site selection, by avoiding image deterioration by the telescope and its environment, and by real time image restoration by adaptive optics. We summarize the principles of adaptive optics, their predicted performance and the current programs underway to implement adaptive optics for astronomical purposes.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988.     

A decade of cost-reduction in very large telescopes (The SST as prototype of special-purpose telescopes)

Many design and technical innovations over the past ten or fifteen years have reduced the costs of very large telescopes by nearly an order of magnitude over those of classical designs. Still a further order of magnitude reduction is possible if the telescope is specialized for on-axis spectroscopy, giving up especially the luxuries of wide field, multiple focal positions, and access to all the sky at will. The SST (Spectroscopic Survey Telescope) with use eighty-five 1 m circular mirrors mounted in a steel frame composed of hundreds of interlocking tetrahedrons, keeping a fixed elevation angle of 60° with rotation only in azimuth. Using an optical fiber it will feed as much light to spectrographs as can be done by a conventional 8 m telescope, yet has a target basic completion cost of only $6 million.Paper presented at the Symposium on the JNLT and Related Engineering Development, Tokyo, November 29–December 2, 1988.     

Observing projects for small telescopes

Suggestions and examples are given for photometric and spectrographic programs with 0.5 - 1.0m telescopes, both at poor and at good sites. The importance is stressed of coordination between observers at sites spread over a region or around the world. As an example of the latter, the Whole Earth Telescope group and their successful observing programs are described.     

Grid integration of robotic telescopes

Robotic telescopes and grid technology have made significant progress in recent years. Both innovations offer important advantages over conventional technologies, particularly in combination with one another. Here, we introduce robotic telescopes used by the Astrophysical Institute Potsdam as ideal instruments for building a robotic telescope network. We also discuss the grid architecture and protocols facilitating the network integration that is being developed by the German AstroGrid‐D project. Finally, we present three user interfaces employed for this purpose. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Fast optics for large telescopes

Reports on two optical designs studied in connection with the JNLT project: namely, the primary corrector and the camera for a spectrograph, are presented.Paper presented at the symposium on the JNLT and Related Engineering Developments, Tokyo, November 2–December 2, 1988.     

Wide-field tracking with zenith-pointing telescopes

Equipped with a suitable optical relay system, telescopes employing low-cost fixed primary mirrors could point and track while delivering high-quality images to a fixed location. Such an optical tracking system would enable liquid-mirror telescopes to access a large area of sky and employ infrared detectors and adaptive optics. Such telescopes could also form the elements of an array in which light is combined either incoherently or interferometrically. Tracking of an extended field requires correction of all aberrations including distortion, field curvature and tilt. A specific design is developed that allows a 10-m liquid-mirror telescope to track objects for as long as 30 min and to point as far as 4° from the zenith, delivering a distortion-free diffraction-limited image to a stationary detector, spectrograph or interferometric beam combiner.     

Infrared interferometry with single telescopes

We examine the merits of three basic interferometric techniques using two-dimensional infrared arrays: speckle interferopmetry, pupil plane interferometry, and speckle holography.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988.