Declination cameras for the meridian circle.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Declination cameras for the meridian circle. Woolsey, E. G. Abstract The Ottawa meridian circle is being modified to include cameras to photograph the division marks on the circle. They have been developed to make use of the mountings and lenses of the microscopes formerly mounted on the east pier. maintained by vaporization of the ices while a stratification of the ices according to vapor pressure at low temperatures is maintained immediately below the meteoric layers. Because of the time lag in heat transfer such a cometary nucleus rotating in the forward sense with respect to its revolution will emit its vaporized ices with a component towards the antapex of motion. The momentum transfer from the kinetic velocity of the emitted gas will propel the nucleus in the forward sense, reduce the mean motion and increase the eccentricity of the orbit. Such orbital effects occur for Comet D'Arrest; the mean daily motion of Comet Wolf I also appears to be increasing. Retrograde rotation can produce an acceleration in mean motion and a decrease in eccentricity as observed for Comet Encke. If the decelerating force component is taken as 41 its maximum theoretical value, the maximum observed acceleration in the mean motion, ~, of Comet Encke, A~/~ = Y0.0001 per revolution, can be produced by a loss of 0.005 of its mass per revolution; the present average rate since 1865 is A~/i = Yo.00004 giving a mass loss of only 0.002. The corresponding mass loss for Comet D'Arrest is the same. For both comets the observed changes in eccentricity are obtained if the force acts proportionately to the solar energy flux but is cut off at a solar distance of about 2 astronomical units. For Comet Wolf I the change in eccentricity corresponding to the observed deceleration in mean motion is too small to be observed. On the basis of this theory Comet Encke might still persist for more than 600 revolutions with an extremely slow diminution in brightness. The observed changes in mean motion lead to a de Publication: The Astronomical Journal Pub Date: 1949 DOI: 10.1086/106309 Bibcode: 1949AJ.....54R.196W full text sources ADS |