Abstract
ALL the naked-eye planets are now absent from the evening sky except Saturn, which is conspicuous and fairly well placed for evening observation: the stellar magnitude will decline from –0.8m to +1 ‘0m during the month, but the planet is rather far south, as also was Jupiter this summer, Saturn's declination being—11 ° 50′ on October 15. Venus is now an early morning object, and will attain its greatest brilliance on October 15. Mars and Jupiter are both near the sun. Uranus will be in opposition on October 27, and there will be a conjunction of Neptune with Venus on October 25, Venus being 2 ° 6′ S. The minor planet Vesta is now in the evening sky, not far from Saturn. Intensive observations on the minor planets have been started at Greenwich, in pursuit of a plan for making greater use of these small objects for determining the position of the equinox. They just show a disc in the 8-in. transit telescope, but resemble a star far more closely than does Venus (and a fortiori the sun), so that the minor planets are very suitable objects to observe in order to tie up the right ascensions and declinations of the solar system with the fundamental right ascensions and declinations of the stars. The principle involved is that the observation of a planet from the earth is equal and opposite to an observation of the earth from the planet, so that besides observing the planet's orbit we observe our own, and find the point where our orbit cuts the equator, that is, the equinox.
Article PDF
Rights and permissions
About this article
Cite this article
The Sky in October. Nature 136, 547 (1935). https://doi.org/10.1038/136547b0
Issue Date:
DOI: https://doi.org/10.1038/136547b0