As far as pointing is concerned, a solar telescope is merely an ordinary astronomical telescope but with enhancements for observing solar and coronal features. The paper discusses the additional coordinate systems that need to be supported, shows how to generate the required solar ephemerides (both orbital and physical), and sets out a suitable application programming interface for the telescope control system to use when making solar observations.

The IAU Commission 4 Working Group on Standardizing Access to Ephemerides recommends the use of the Spacecraft and Planet Kernel (SPK) format as a standard format for the position ephemerides of planets and other natural solar system bodies, and the use of the Planetary Constants Kernel (PCK) format for the orientation of these bodies. It further recommends that other supporting data be stored in a text PCK. These formats were developed for use by the SPICE Toolkit by the Navigation and Ancillary Information Facility of NASA's Jet Propulsion Laboratory (JPL). The CALCEPH library developed by the Institut de mecanique celeste de calcul des ephemerides (IMCCE) is also able to make use of these files. High accuracy ephemerides available in files conforming to the SPK and PCK formats include: the Development Ephemerides (DE) from JPL, Integrateur Numerique Planetaire de l'Observatoire de Paris (INPOP) from IMCCE, and the Ephemerides Planets and the Moon (EPM), developed by the Institute for Applied Astronomy (IAA). The bulk of this report is a description of the portion of PCK and SPK formats required for these ephemerides. New SPK and PCK data types, both called Type 20: Chebyshev (Velocity Only), have been added. Other changes to the specification are (i) a new object identification number for coordinate time ephemerides and (ii) a set of three new data types that use the TCB rather than the TDB time scale for the ephemerides, but are otherwise identical to their TDB versions.

The extensible N-Dimensional Data Format (NDF) was designed and developed in the late 1980s to provide a data model suitable for use in a variety of astronomy data processing applications supported by the UK Starlink Project. Starlink applications were used extensively, primarily in the UK astronomical community, and form the basis of a number of advanced data reduction pipelines today. This paper provides an overview of the historical drivers for the development of NDF and the lessons learned from using a defined hierarchical data model for many years in data reduction software, data pipelines and in data acquisition systems.

In this tutorial we summarize the physics and mathematics behind refractive electromagnetic wave bending and delay. Refractive bending and delay through the Earth's atmosphere at both radio/millimetric and optical/IR wavelengths are discussed, but with most emphasis on the former, and with Atacama Large Millimeter Array (ALMA) applications in mind. As modern astronomical measurements often require subarcsecond position accuracy, care is required when selecting refractive bending and delay algorithms. For the spherically-uniform model atmospheres generally used for all refractive bending and delay algorithms, positional accuracies less than or similar to 1 '' are achievable when observing at zenith angles less than or similar to 75 degrees. A number of computationally economical approximate methods for atmospheric refractive bending and delay calculation are presented, appropriate for astronomical observations under these conditions. For observations under more realistic atmospheric conditions, for zenith angles less than or similar to 75 degrees, or when higher positional accuracy is required, more rigorous refractive bending and delay algorithms must be employed. For accurate calculation of the refractive bending, we recommend the Auer and Standish method, using numerical integration to ray-trace through a two-layer model atmosphere, with an atmospheric model determination of the atmospheric refractivity. For the delay calculation we recommend numerical integration through a model atmosphere.

From region to region and even within states, the energy-efficiency program industry uses different terminology. Definitions of such key terms as lifecycle savings, net savings, and incentives vary depending on the jurisdiction. This diversity in semantics is a natural product of the different values and approaches that each state’s policymakers have adopted for energy efficiency but makes “apples-to-apples” aggregation of program inputs and outputs difficult and less meaningful. Inconsistency in efficiency program data poses a barrier to quantifying the energy efficiency resource on a regional and national basis and therefore undermines the notion that this resource is a material contributor to energy needs. Lawrence Berkeley National Laboratory (LBNL) has assembled a national taxonomy of energy efficiency (EE) programs and a common terminology for data on energy savings, program spending and other metrics for characterizing customer-funded efficiency programs. This common lexicon was founded on the work of the EM&V Working Group of the State and Local Energy-Efficiency Action Network (SEE Action), augmented with extensive reviews of programs in a majority of states by LBNL, the Consortium for Energy Efficiency and other national and regional organizations. CEE worked with LBNL to adapt this taxonomy for its State of the Efficiency Program Industry survey, fielded annually to efficiency program administrators across the US and Canada. LBNL and CEE will describe the practical usefulness of the program taxonomy and data glossary in analyses of the energy efficiency industry. LBNL staff will discuss the value of its adoption by a variety of energy sector stakeholders.

Precession is the secular and long-period component of the motion of the Earth’s spin axis in the celestial reference frame. The current precession model, IAU 2006, approximates this motion by polynomial expansions that are valid, with very high accuracy, in the immediate vicinity (a few centuries) of the reference epoch J2000.0. However, for more distant epochs, this approximation quickly deteriorates. Consequently, we recently published new precession expressions (Vondrák et al. 2011b), comprising very long-period terms fitted to a numerical integration of the motion of solar system bodies on scales of several hundreds of millennia. We give a short description of the new expressions, including an assessment of their accuracy and comparisons with other models.

In our preceding study (Vondrák et al. 2009) we formulated developments for the precessional contribution to the CIP X,Y coordinates suitable for use over long time intervals. They were fitted to IAU 2006 close to J2000.0 and to the numerical integration of the ecliptic (using the integrator package Mercury 6) and of the general precession and obliquity (using Laskar’s solution LA93) for more distant epochs. Now we define the boundary between precession and nutation (both are periodic) to avoid their overlap. We use the IAU 2006 model (that is based on the Bretagnon’s solution VSOP87 and the JPL planetary ephemerides DE406) to represent the precession of the ecliptic close to J2000.0, a new integration using Mercury 6 for more distant epochs, and Laskar’s LA93 solution to represent general precession and obliquity. The goal is to obtain new developments for different sets of precession angles that would fit to modern observations near J2000.0, and at the same time to numerical integration of the translatory-rotatory motions of solar system bodies on scales of several thousand centuries.

The Cornell Caltech Atacama Telescope1 is a 25m aperture sub-millimeter wavelength telescope to be built in northern Chile at an altitude of 5600m. Like any modern telescope, CCAT will require a powerful and comprehensive control system; writing one from scratch is not affordable, so the CCAT TCS must be based, at least in part, on existing software. This paper describes how the search for a suitable system (or systems) was carried out, looks at the criteria used to judge the feasibility of various approaches to developing the new system, and suggests the further studies needed to validate the choices. Although the purpose of the study was to find a control system for a specific telescope with its own particular technical requirements, many of the factors considered, such as maintainability, the ability to adapt to new requirements in the future and so on, are of concern to all telescopes. Consequently, the processes used to select the system for CCAT are relevant to other projects faced with the same decision, even if the conclusions turn out to be different.

The precession-nutation models based on the IAU 2000A nutation series involve several thousand amplitude coefficients, many under 1� as in size, and the sines and cosines of about 1350 angles. For the many applications that do not require the utmost accuracy this represents an unnecessary or even excessive computational overhead. The IAU 2000B model offers one alternative, an order of magnitude smaller than IAU 2000A and delivering classical nutation components of 1 mas accuracy in the current era. In a recent paper (Capitaine & Wallace 2007), the main results of which are provided here, we looked at other options, based on series for the CIP coordinates and the CIO locator and with the GCRS to CIRS rotation matrix as the end product. Truncation of the series provides most of the savings, but certain other measures can be taken also. Three example formulations are presented that achieve 1 mas, 16 mas and 0.4 arcsec accuracy throughout 1995-2050 with computational costs 1, 2 and 3 orders of magnitude less than the full models. A few examples of possible applications are presented.

The precession-nutation models based on the IAU 2000A nutation series involve several thousand amplitude coefficients, many under 1μas in size, and the sines and cosines of about 1350 angles. For the many applications that do not require the utmost accuracy this represents an unnecessary or even excessive computational overhead. The IAU 2000B model offers one alternative, an order of magnitude smaller than IAU 2000A and delivering classical nutation components of 1 mas accuracy in the current era. In a recent paper (Capitaine & Wallace 2007), the main results of which are provided here, we looked at other options, based on series for the CIP coordinates and the CIO locator and with the GCRS to CIRS rotation matrix as the end product. Truncation of the series provides most of the savings, but certain other measures can be taken also. Three example formulations are presented that achieve 1 mas, 16 mas and 0.4 arcsec accuracy throughout 1995-2050 with computational costs 1, 2 and 3 orders of magnitude less than the full models. A few examples of possible applications are presented.

The accuracy requirements for pointing a ground-based telescope or antenna are comparatively modest; the latest Earth orientation models used by specialists have precision goals measured in microareseconds and are excessive for such humble applications. Abridged formulations offer an attractive alternative: easier to get right, and much quicker to compute. Moreover, the revised computational procedures that the IAU introduced in 2000 to assist high-precision studies of Earth rotation lend themselves to approximation. Together with basic models for aberration and refraction, a page of inline C code is enough to predict the observed altazimuth coordinates of a star to an accuracy of 1-2 arcseconds, which is adequate for pointing a small telescope. This can be complemented by a similarly concise formulation of the basic pointing corrections for an equatorial or altazimuth mount.

Context. The IAU 2000/2006 precession-nutation models have precision goals measured in microarcseconds. To reach this level of performance has required series containing terms at over 1300 frequencies and involving several thousand amplitude coefficients. There are many astronomical applications for which such precision is not required and the associated heavy computations are wasteful. This justifies developing smaller models that achieve adequate precision with greatly reduced computing costs.Aims. We discuss strategies for developing simplified IAU 2000/2006 precession-nutation procedures that offer a range of compromises between accuracy and computing costs.Methods. The chain of transformations linking celestial and terrestrial coordinates comprises frame bias, precession-nutation, Earth rotation and polar motion. We address the bias and precession-nutation (NPB) portion of the chain, linking the Geocentric Celestial Reference System (GCRS) with the Celestial Intermediate Reference System (CIRS), the latter based on the Celestial Intermediate Pole (CIP) and Celestial Intermediate Origin (CIO). Starting from direct series that deliver the CIP coordinates X, Y and (via the quantity s + XY/2) the CIO locator s, we look at the opportunities for simplification.Results. The biggest reductions come from truncating the series, but some additional gains can be made in the areas of the matrix formulation, the expressions for the nutation arguments and by subsuming long period effects into the bias quantities. Three example models are demonstrated that approximate the IAU 2000/2006 CIP to accuracies of 1 mas, 16 mas and 0.4 arcsec throughout 1995-2050 but with computation costs reduced by 1, 2 and 3 orders of magnitude compared with the full model.

AbstractA Division 1 Working Group on “Nomenclature for Fundamental Astronomy” (NFA) was formed at the 25th IAU GA in 2003 in order to provide proposals for the new nomenclature associated with the implementation of the IAU 2000 resolutions on reference systems. This WG is also intended to make related educational efforts for addressing the issue to the large community of scientists. The activities of the NFA WG since October 2003 have consisted of newsletters, questionnaires, detailed e-mail discussion, and the preparation of WG recommendations and guidelines which are supported by explanatory documents. The NFA documents have been discussed during international meetings in 2004 and 2005. A NFA WG resolution proposal will be submitted to the IAU 2006 GA as a supplement to the IAU 2000 resolutions. The NFA material has been made available on the NFA web Bite at:http://syrte.obspm.fr/iauWGnfa/.