Engineering topics
Publications and source records attributed to Thekaekara, M. P..
The values of the solar constant and solar spectrum are presented which are proposed as revised standards for science and technology. A solar constant value of 1.94 cal/sq cm min or 135.3 mW/sq cm was proposed. A detailed spectral irradiance table is given for the range of 0.12 to 1000 microns.
Description of an international comparison of radiometers made on May 10 through 14, 1971, with 24 instruments, each one representing the calibration standard of a different country or a major laboratory. All were pyranometers, viewing the sun and sky, thus bypassing the conventional method of transferring the standard from Angstrom pyrheliometers. This is the first time that pyranometers from all around the globe have been brought together in order to verify the scale on which to report solar radiation data. A highly accurate data collection system measured simultaneously the output of each instrument and that of a reference standard at 20-sec intervals. Over 300,000 radiometric signals were recorded under varying atmospheric conditions, as well as data on turbidity, temperature, and other relevant parameters. Computer programs were developed for overnight analysis of the data and distribution to participants on the following day. Among major findings are that instruments of different types and independent calibration such as those of Eppley, U. S. A., World Radiation Center, Switzerland, and Melbourne, Australia, show better agreement than anticipated, that certain national standards have to be revised by as much as 16% and that the cosine factor is highly dependent on the type of instrument.
Solar constant and spectral energy distribution standard values by high altitude aircraft, balloon and spacecraft measurements
Solar constant and solar spectrum measured from research aircraft
Solar constant and zero air mass spectrum, discussing new standard values
Spectral irradiance measurements of tungsten and carbon filament lamps for energy standards and accuracy limits used in space simulators
Engineering standard for solar constant and zero air mass solar spectral irradiance from high altitude measurements
Quantum mechanics of line broadening effects in solar simulator mercury xenon arc lamp spectra
Light transmittance measurements through thick plate of optical material
Solar constant and spectral irradiance curve for zero air mass obtained from aircraft measurements
Solar irradiance spectral distribution data normalized and combined with spectral absorptance of satellite surface coatings, obtaining absorbed energy for spectral range
Solar constant and solar spectral irradiance measurements from high altitude research aircraft, discussing radiation measuring instruments
Calibration of working standards of spectral irradiance of quartz iodine lamps
Spectral irradiance measurements on solar simulator sources
Automatic dielectric film filter method in spectrophotometry
Mercury pool with a cover layer of high viscosity oil provides a reference reflector for precise alignment of optical instruments. The cover layer effectively damps any ripples in the mercury from support structure vibrations.
Mercury pool gravity reference system establshing fixed direction to which angles precisely measured by autocollimators can be referred
Solar constant, spectral distribution of solar radiant flux, solar radiation laws and simulation, spacecraft thermal balance, and radiation measurement scale