The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform

D.l. Mickey - One of the best experts on this subject based on the ideXlab platform.

  • Alignment of Fabry-Pérot Interferometer Plates in a Solar Vector Magnetograph
    Solar Physics, 2004
    Co-Authors: D.l. Mickey
    Abstract:

    I describe a method for quickly and accurately determining the plate parallelism in a tunable Fabry-Pérot interferometer. The method takes advantage of the fact that our Fabry-Pérot is installed in a spectropolarimeter: we measure profiles of solar or telluric absorption lines in three differently polarized telescope subapertures and use the residual polarization profiles to determine the plate parallelism error. An example of the error as a function of time during the observing day is also shown; it changes in a consistent way with telescope Hour Angle but the drift is enough to require frequent adjustment.

  • Alignment of Fabry-Pérot Interferometer Plates in a Solar Vector Magnetograph
    Solar Physics, 2004
    Co-Authors: D.l. Mickey
    Abstract:

    I describe a method for quickly and accurately determining the plate parallelism in a tunable Fabry-Perot interferometer. The method takes advantage of the fact that our Fabry-Perot is installed in a spectropolarimeter: we measure profiles of solar or telluric absorption lines in three differently polarized telescope subapertures and use the residual polarization profiles to determine the plate parallelism error. An example of the error as a function of time during the observing day is also shown; it changes in a consistent way with telescope Hour Angle but the drift is enough to require frequent adjustment.

Nikola Solaric - One of the best experts on this subject based on the ideXlab platform.

  • automatic grid azimuth by Hour Angle of the sun a star or a planet using an electronic theodolite kern e2
    Astrophysics and Space Science, 1991
    Co-Authors: Nikola Solaric
    Abstract:

    The paper deals with the automatic grid azimuth determination of an object on the earth using the electronic theodolite Kern E2 by observing the sun, a star, or a planet. The observation time and the readings of horizontal and vertical circles of the electronic theodolite enter automatically the electronic calculator Hewlett-Packard HP41CX. The calculator computes the grid azimuth of the terrestrial object and directs the observer what to do. Therefore, even a personnel without specific high education can make observations. For the solar observations it is not necessary to have an astronomical almanac, because the program computes the solar coordinates. The general input data, together with the measured ones, can be stored on a magnetic cassette and later on, if necessary, one can correct the general data and recalculate the azimuth. The method proved to be very practical in the field work.

Dietrich Labs - One of the best experts on this subject based on the ideXlab platform.

  • The role of telescopic stray light in limb-darkening scans obtained in April 1981 (and later)
    Solar Physics, 1990
    Co-Authors: Heinz Neckel, Dietrich Labs
    Abstract:

    The suspicion of Elste (1990), that telescopic stray light together with imperfect collimation of telescope and spectrograph could be a possible explanation for the systematic differences and variations found by Neckel and Labs (1987) in many limb-darkening scans, proves to be unfounded for the following reasons: (1)The collimation was performed very precisely; (2) the telescope mirrors remained fixed in position and direction during most of the observing period; (3) stray light effects depending on Hour Angle were not detectable; (4) in the same collimation status, also many almost symmetric scans had been recorded; (5) the observed east-west differences in the solar intensities are partly even larger than the total amount of stray light (from telescope and sky!) observed as ‘sky’-background just outside the limb; (6) any east-west differences in the ‘sky’-background near the limb are just a few 0.01% of the disk center intensity; (7) the differences of the average intensities along eastern and western radius appear to be correlated with the east-west differences of the intensity's R.M.S.

Jiangfeng Wang - One of the best experts on this subject based on the ideXlab platform.

  • a new combined cooling heating and power system driven by solar energy
    Renewable Energy, 2009
    Co-Authors: Jiangfeng Wang
    Abstract:

    A new combined cooling, heating and power (CCHP) system is proposed. This system is driven by solar energy, which is different from the current CCHP systems with gas turbine or engine as prime movers. This system combines a Rankine cycle and an ejector refrigeration cycle, which could produce cooling output, heating output and power output simultaneously. The effects of Hour Angle and the slope Angle of the aperture plane for the solar collectors on the system performance are examined. Parametric optimization is conducted by means of genetic algorithm (GA) to find the maximum exergy efficiency. It is shown that the optimal slope Angle of the aperture plane for the solar collectors is 60°at 10 a.m. on June 12, and the CCHP system can reach its optimal performance with the slope Angle of 45°for the aperture plane at midday. It is also shown that the system can reach the maximum exergy efficiency of 60.33% under the conditions of the optimal slope Angle and Hour Angle.

George Pantazis - One of the best experts on this subject based on the ideXlab platform.

  • astronomical azimuth determination by the Hour Angle of polaris using ordinary total stations
    Survey Review, 2008
    Co-Authors: E Lambrou, George Pantazis
    Abstract:

    AbstractThe determination of the astronomical azimuth of a line is not a difficult task for surveyors any more. The aim of this paper is to analyze the theoretical details and errors in order to propose the use of ordinary total stations, for an easy, efficient and accurate determination of the astronomical azimuth of a line by the Hour Angle method via Polaris sightings. As many modern total stations have a built – in quartz clock they can register automatically the UTC time as well as the Angle measurements (horizontal and zenith) of each observation. The total fieldwork time needed is about 10 minutes and the accuracy that may be achieved is about ± 2". This procedure will be proven to be easier than the determination of the geodetic azimuth of the same line. The calculation is independent and the result is free of the errors that the coordinates of a survey mark may contain, because they are not used. However good positional data is required from other sources. Astronomical azimuths are an alternative...