scholarly journals XVII. Some further observations on atmospherical refraction

1814 ◽  
Vol 104 ◽  
pp. 337-347
Keyword(s):  
General Formula ◽  
Royal Society ◽  
Small Error ◽  
Zenith Distance ◽  
High Latitudes ◽  
The Moon ◽  
Winter Solstice ◽  
Light Passing ◽  
Convenient Formula ◽  
The Mean

In my former paper on atmospherical refraction, communi­cated to the Royal Society by my late friend, Dr. Maskelyne, I considered the few observations made below 80° of zenith distance, as not sufficiently to be depended on, for the compu­tation of a general formula of refraction: and I therefore used ŋ Ursæ Majoris (78° 10' zen. dis.) as the lowest star for that purpose. Having since applied the computed refraction from the formula thence obtained, to observations of stars below 80°, I have noticed, that such stars so corrected, appeared to be further from the zenith below the Pole, than they ought to have been, from the observations above the Pole: and there­fore that the refraction was less at those distances from the zenith, than I had assumed. This has induced me, in the years 1811 and 1812, to make a course of observations of stars below the Pole, above 80° zenith distance; and as near to the horizon, as the trees in Greenwich Park would permit; these being higher than the level of my Observatory. It may also be remarked, that those stars in my former table below 80°, produce the co-latitude in excess; as a confirmation, that the same formula will not apply to those larger arcs, where, from the rapid increase of the tangents, a small error in the assumed quantity becomes more sensible. Although various hypotheses may be formed, from the known density and temperature of the atmosphere; and from these causes may be computed the effect they should have on a ray of light passing through the same: yet we must resort to observation, for the verification of the theory; and reduce the quantity so found, to the most simple and convenient formula. I shall proceed to deduce, from this course of observations, such formulae as will appear to result, for the computation of the refraction; from the zenith, to the lowest star which I have observed: these may be considered as sufficient for the observation of the sun at the winter solstice, in high latitudes since those of the moon, from its great parallax, and the planets from their general invisibility, would probably not be attempted. Never­theless, it is to be wished, as a matter of curiosity, or from which some useful deductions might be made, that in those Observatories, wherein from their elevated situations it might be practicable, the true quantity of refraction should be ascertained to the horizon. Of all the formulae for computing the mean refraction, that proposed and used by Dr. BRADLEY, is the most convenient and applicable for the practical astronomer. But as it is now acknowledged, that the numbers he had assumed for the co­efficient of r (the refraction ; ) and of x (the quantity at 45°) were too small: their real values will appear to be the mean of several arcs, and such as I now propose to be adopted. I have found, that the same formula will serve to 87° of zenith distance; possibly this might not happen in low situations, where the height of the vapours would form a greater angle with the horizon: yet in more elevated places, we may rea­sonably suppose, that a general formula might be carried nearly to the horizon.

scholarly journals The results of observations made at the observatory of Trinity College, Dublin, for determining the obliquity of the ecliptic, and the maximum of the aberration of light

1833 ◽  
Vol 2 ◽  
pp. 114-115
Keyword(s):  
Trinity College ◽  
Sufficient Accuracy ◽  
Zenith Distance ◽  
The Sun ◽  
Summer Solstice ◽  
Winter Solstice ◽  
Trinity College Dublin ◽  
The Mean

The obliquity of the ecliptic, as deduced from the early observations by the Greenwich quadrant, compared with the present obliquity, gives the diminution for an interval of nearly sixty years, with almost sufficient accuracy to state with some confidence the mass of Venus; but to obtain this point with certainty, the present obliquity, deduced from a mean of the observations of different astronomers, should be used. Upon this subject the author alludes to the opinion of astronomers, that observations of the winter solstice have given a less obliquity than those of the summer solstice,—an opinion sustained by the observations of Maskelyne, Arago, and Pond, but questioned by Bessel and Bradley. Dr. Brinkley refers this difference to some unknown modification of refraction; he has observed that at the winter solstice the irregularity of refraction for the sun is greater than for the stars at the same zenith-distance. He points out the necessity of paying attention to the observations at the winter solstice, and gives a table, exhibiting the mean obliquity reduced to January 1813. Dr. Brinkley next alludes to the maximum of the aberration of light, which appears from his observations of last year to be 20"·80.

scholarly journals On the meteorological observations made at the apartments of the Royal Society, during the year 1827, 1828, and 1829

1837 ◽  
Vol 3 ◽  
pp. 42-43
Keyword(s):  
Royal Society ◽  
Limited Range ◽  
Diurnal Variations ◽  
The Moon ◽  
French Academy ◽  
Annual Variations ◽  
The Mean ◽  
Meteorological Observations ◽  
Academy Of Sciences

The author first inquires into the annual and diurnal variations of the barometer and thermometer, for the determination of which he takes the mean of the observations in each month made at the Apartments of the Royal Society, during the years 1827,1828, and 1829; and also that deduced from Mr. Bouvard’s observations, published in the Memoirs of the French Academy of Sciences. From the table given it would appear that the annual variations are independent of the diurnal variations. A much greater number of observations than we possess at present, made frequently and at stated times each day, are requisite before any very satisfactory conclusion can be deduced as to the influence of the moon on the fluctuations of the barometer. The author, however, has attempted the inquiry, as far as the limited range of the present records will allow, by classifying all the observed heights, corresponding to a particular age of the moon, as defined by her transit taking place within a given half hour of the day; and thence deducing mean results, which are exhibited in tables. The results afforded by the observations at Somerset House differ widely from those obtained from corresponding observations made at the Paris Observatory. According to the former, the barometer is highest at new and full moons, and lowest at the quadratures the extent of the fluctuations being 0.08 of an inch: according to the lottery the controly is the esse, and the extent is only 0.05 of an inch.

scholarly journals IV. Lunar influence on temperature

1865 ◽  
Vol 14 ◽  
pp. 223-228 ◽  
Keyword(s):  
Royal Society ◽  
The Moon ◽  
The Third ◽  
The Mean ◽  
Vexed Question

The tabulation of an unbroken series of thermometric observations for the several days of the lunation during fifty years having been completed up to November 1864, and an amount of lunar action detected which appears sufficient to set at rest the long vexed question of the moon’s influence over our atmosphere, I venture to think that the time has arrived when it becomes a duty to lay the results of the investigation before the Royal Society. In 1856 the frequent recurrence of higher temperatures about the eighth or ninth day of the moon’s age, led to an examination and comparison of the mean temperatures of the third day before, and the second day after first quarter of the moon, for a series of seven years at Chiswick, and sixteen years at Dublin. The results showed conclusively that the temperature of the second day after first quarter was higher than the temperature of the third day before that phase during the years in question.

scholarly journals The Bakerian lecture. - On the radiation of heat from the moon, the law of its absorption by our atmosphere, and its variation in amount with her phases

1873 ◽  
Vol 21 (139-147) ◽  
pp. 241-242 ◽  
Keyword(s):  
Royal Society ◽  
Zenith Distance ◽  
The Moon ◽  
Single Curve ◽  
The Subject ◽  
The Law ◽  
Made In

In this paper is given an account of a series of observations made in the Observatory of Birr Castle, in further prosecution of a shorter and less carefully conducted investigation, as regards many details, which forms the subject of two former communications to the Royal Society. The observations were first corrected for change of the moon’s distance from the place of observation and change of phase during the continuance of each night’s work, and thus a curve, whose ordinates represented the scale-readings (corrected) and whose abscissas represented the corresponding altitudes, was obtained for each night’s work. By combining all these, a single curve and table for reducing all the observations to the same zenith-distance was obtained, which proved to be nearly, but not quite, the same as that found by Professor Seidel for the light of the stars.

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

Essai d'application de modèles météorologiques au calcul du moment d'apparition de deux phases phénologiques | Application of Meteorological Models for the Calculation of the Beginning of Two Phenological Phases

2000 ◽  
Vol 151 (10) ◽  
pp. 385-397
Author(s):  
Bernard Primault
Keyword(s):  
Sunshine Duration ◽  
Fruit Trees ◽  
Swiss Alps ◽  
Winter Solstice ◽  
Phenological Data ◽  
Thermal Thresholds ◽  
The Mean ◽  
Two Parameters ◽  
Meteorological Models ◽  
Phenological Phases

Many years ago, a model was elaborated to calculate the«beginning of the vegetation's period», based on temperatures only (7 days with +5 °C temperature or more). The results were correlated with phenological data: the beginning of shoots with regard to spruce and larch. The results were not satisfying, therefore, the value of the two parameters of the first model were modified without changing the second one. The result, however, was again not satisfying. Research then focused on the influence of cumulated temperatures over thermal thresholds. Nevertheless, the results were still not satisfying. The blossoming of fruit trees is influenced by the mean temperature of a given period before the winter solstice. Based on this knowledge, the study evaluated whether forest trees could also be influenced by temperature or sunshine duration of a given period in the rear autumn. The investigation was carried through from the first of January on as well as from the date of snow melt of the following year. In agricultural meteorology, the temperature sums are often interrelated with the sunshine duration, precipitation or both. However,the results were disappointing. All these calculations were made for three stations situated between 570 and 1560 m above sea-level. This allowed to draw curves of variation of the two first parameters (number of days and temperature) separately for each species observed. It was finally possible to specify the thus determined curves with data of three other stations situated between the first ones. This allows to calculate the flushing of the two tree species, if direct phenological observation is lacking. This method, however, is only applicable for the northern part of the Swiss Alps.

scholarly journals On tho proportions of the prevailing winds, the mean temperature, and depth of rain in the climate of London, computed through a cycle of Eighteen Years, or periods of the Moon’s declination

1843 ◽  
Vol 4 ◽  
pp. 300-300
Keyword(s):  
The Moon ◽  
Fair Weather ◽  
North West ◽  
West Wind ◽  
North East ◽  
East Wind ◽  
The North ◽  
The Common ◽  
The Mean ◽  
Solar Influence

In this paper the author investigates the periodical variations of the winds, rain and temperature, corresponding to the conditions of the moon’s declination, in a manner similar to that he has already followed in the case of the barometrical variations, on a period of years extending from 1815 to 1832 inclusive. In each case he gives tables of the average quantities for each week, at the middle of which the moon is in the equator, or else has either attained its maximum north or south declination. He thus finds that a north-east wind is most promoted by the constant solar influence which causes it, when the moon is about the equator, going from north to south; that a south-east wind, in like manner, prevails most when the moon is proceeding to acquire a southern declination ; that winds from the south and west blow more when the moon is in her mean degrees of declination, going either way, than with a full north or south declination ; and that a north-west wind, the common summer and fair weather wind of the climate, affects, in like manner, the mean declination, in either direction, in preference to the north or south, and most when the moon is coming north. He finds the average annual depth of rain, falling in the neighbourhood of London, is 25’17 inches.

scholarly journals The lunar and solar diurnal variations of water-level in a well at Kew observatory, Richmond

1918 ◽  
Vol 94 (663) ◽  
pp. 476-478
Keyword(s):  
Water Level ◽  
Royal Society ◽  
Correlation Coefficients ◽  
Barometric Pressure ◽  
Diurnal Variations ◽  
Range Of Movement ◽  
Nearest Point ◽  
Similar Relation ◽  
Short Period ◽  
The Mean

In a paper communicated to the Royal Meteorological Society, it was shown that the experimental well at Kew Observatory responded to the lunar fortnightly oscillation of mean level in the River Thames, which is 300 yards from the Observatory at its nearest point. The sensitiveness of the water-level to barometric pressure has also been investigated, and the results have been given in a paper recently read before the Royal Society. The present paper deals with the effects of the short-period tides in the solar and lunar series, S 1 , S 2 , S 3 , S 4 , and M 1 , M 2 , M 3 , M 4 . Two-hourly measurements, both in lunar and solar time, were made on the traces obtained during the first two years, August, 1914-August, 1916, omitting days of very irregular movement. Monthly mean inequalities were then computed. Well marked solar and lunar diurnal variations were found in each month, taking the form of double oscillations with two maxima and two minima during the 24 hours. The range of movement was in each case found to be highly associated with the mean height of the water in the well, the correlation coefficients being 0·89 (lunar) and 0·90 (solar). A similar relation had been previously found to exist in the case of barometric pressure.

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