Responds to TM's query in his 1835-1-17 about the effect that motion of the center of the mural circle would have on the microscopic readings.
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Responds to TM's query in his 1835-1-17 about the effect that motion of the center of the mural circle would have on the microscopic readings.
Additional approaches to resolving TM's mural circle problem [see JH's 1835-2-5].
More on the mural circle [see JH's 1835-2-7].
Some comments about constant error in TM's observations.
About the difficulty of measuring high and low tide with the instruments available to TM; offers the design of an instrument that would measure the mid-point between high and low tides.
Excited about JH's observations, and has shown them to several people.
Sends TM some tide observations, and some calculations done on them.
Believes that TM is the first to see the return of Halley's Comet [see TM's 1835-9-1].
Still struggling with the problems inherent in using the mural circle; the comet has apparently been seen by JH's mechanic, John Stone, prior to having been sighted by TM.
Sends information about where to look for Encke's comet.
Has not had any success in finding comets.
Is intrigued by the apparent displacement of several planetary nebulae from the positions found in the catalogues of other observers. Does not know what to think.
JH is chagrined to note that he forgot to observe the equinox, after having impressed on any and all the need to do so.
Asks TM to measure the position of some stars that are difficult for JH to observe.
Sends a list of additional stars to be measured for JH to use as standards.
About an anomaly in one of JH's lists of observations.
About the principles whereby the nomenclature of the constellations might be reformed.
Has installed his astrometer to help judge star magnitudes; also makes a comparison of barometric observations with those of TM.
Has compared TM's observational measurements with those of the Brisbane catalogue, and finds TM's observations to be better; is working on a star photometer.
JH's observations of the comet [Halley's], together with comments on constellation nomenclature and stellar magnitudes.