Abstract
In the brief account of the transit instrument which I had the honour some time ago of presenting to the Royal Society, I stated the circumstance of the instrument's deviation from the meridian arising from the unequal expansion of its braces; but no instance was then given of the magnitude of such deviation. I now subjoin one. On the morning of Oct. 15, (civil reckoning) after observing the passage of Regulus, the southern shutters were accidentally left open, so that when I returned to observe the inferior culmination of the pole star, the sun was shining on the upper western brace, the object-glass of the instrument being towards the zenith. The effect of this was a retardation of more than 25 seconds in the star's passage, as will thus appear: I now view, with great suspicion, all the observations of the sun's transits, which I observed previously to the detection of that source of inequality which is the subject of the present, and of my former communication.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Philosophical Transactions of the Royal Society of London
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.