Sidereal time

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2015 ◽  
Keyword(s):  
Sidereal Time

scholarly journals On The Use of Mean Sidereal Time

1951 ◽  
Vol 111 (6) ◽  
pp. 619-623 ◽  
Author(s):  
R. d'E. Atkinson ◽  
D. H. Sadler
Keyword(s):  
Sidereal Time

A two-way sidereal anisotropy

1968 ◽  
Vol 46 (10) ◽  
pp. S611-S613 ◽  
Author(s):  
K. Nagashima ◽  
H. Ueno ◽  
S. Mori ◽  
S. Sagisaka
Keyword(s):  
Time Variation ◽  
Cosmic Ray ◽  
Sidereal Time ◽  
Cosmic Ray Intensity ◽  
Data Support ◽  
Ion Chambers ◽  
Using Data ◽  
Sidereal Anisotropy

The sidereal time variation is analyzed using data for the ion chambers at Cheltenham and Christchurch for the period 1938–58 and for the meson and neutron components during the IGY. All the results derived from these three kinds of data support the existence of a two-way sidereal anisotropy, suggested by Jacklyn, which has two maxima of the cosmic-ray intensity in the directions of 8 h and 20 h S.T. (sidereal time).

scholarly journals XIX. On the difference of meridians of the Royal Observatories of Greenwich and Paris

1827 ◽  
Vol 117 ◽  
pp. 286-296 ◽  
Keyword(s):  
The Other ◽  
Detailed Account ◽  
Sidereal Time ◽  
Methods Of Calculation ◽  
Royal Observatory ◽  
The Difference ◽  
Made In

In the Philosophical Transactions for 1826, Part II. Mr. Herschel has given a detailed account of observations, which were made in the month of July, 1825, for the purpose of ascertaining the difference of the meridians of the Royal Observatories of Greenwich and Paris, with a computation of these observations, from which the most probable value of the difference of longitude appears to be 9 m 21 s. 6. But I have perceived that in the copy of the observations delivered to him from the Royal Observatory of Greenwich, an error of one second has been committed; as the true sidereal time of the observation made there on 21st July, ought to be 17 h 38 m 57·12 in place of 17 h 38 m 56 s. 10, set down in the Table p. 104, which he informs me was computed at the Observatory, and officially communicated to him from the Astronomer Royal. This error seems to have had its origin in the little Table at the bottom of page 103; for, on subtracting the error of the clock, 47 s. 37, from the time 18 h 8 m 30 s. 40, the true sidereal time is 18 h 7 m 43 s. 03, instead of 18 h 7 m 42 s. 03, there given. The error in the result of that day’s observations, arising from this cause, has been partly compensated by a mistake of three tenths of a second, which has occurred in calculating the combined observations of the same day, the gain of mean on sidereal time being stated to be — 4 s. 54 (pp. 120 and 122), in place of — 4 s. 24. On checking the other observations, a few trifling alterations appear to be necessary upon the Greenwich Table of sidereal time, from the data given along with it. These seem to be occasioned by different methods of calculation, and indeed are hardly worthy of notice. The French astronomers not having given the data on which the calculations of the sidereal times at Paris are founded, they are assumed to be correct.

scholarly journals Perturbing Effects in Past Optical Astrometric Data. Statistical Modelisation and Separation

1993 ◽  
Vol 156 ◽  
pp. 101-106
Author(s):  
M. L. Bougeard
Keyword(s):  
Sidereal Time ◽  
Multivariate Statistical ◽  
Earth Orientation Parameters ◽  
Time Effects ◽  
Preliminary Step ◽  
The Earth ◽  
Observer Effects ◽  
Astrometric Data ◽  
Orientation Parameters ◽  
Detection And Separation

Past optical astrometric observations are to be re-reduced in order to get a new evaluation of the Earth Orientation Parameters in the more accurate Hipparcos reference frame. Among the selected instruments is the Paris astrolabe, considered here. In this Paper, through multivariate statistical procedures, we deal with the preliminary step of the new evaluation which consists in detection and separation of sources of significant inconsistency and outstanding errors in the Paris reductions so far performed. The analysis is performed over two test periods — one per instrumental setting-that are compared in particular in terms of observer effects, magnitude, colour and sidereal time effects. The Paper also gives a synthetic overview on the statistical methods we used to obtain the main results so that they can be applied to other astrometric data.

A re-interpretation of the definition of UT1

1988 ◽  
Vol 128 ◽  
pp. 39-40
Author(s):  
A. T. Sinclair
Keyword(s):  
Time Scale ◽  
Universal Time ◽  
Sidereal Time ◽  
Broad Definition ◽  
The Earth ◽  
Average Person ◽  
Rotation Of The Earth ◽  
Definition Of ◽  
Sidereal Rotation

SummaryUniversal time is a commonplace quantity, and yet it has no generally accepted definition. The expression for sidereal time is often quoted as a definition, but this does not convey much meaning to the average person. Also sidereal time is measured from the equinox of date, and so involves the precession formulae of the stellar reference frame, and hence may not be ideal for other modern techniques of observation. Guinot (1979) has proposed a broad definition of UT1:“UT1 is an angle which is proportional to the sidereal rotation of the Earth, the coefficient of proportionality being chosen so that UT1, in the long term, remains in phase with the alternation of day and night. In some applications, UT1 can be considered as a non-uniform time scale”.

scholarly journals Secular Variations in Optical Observations of Planets: Summary

1992 ◽  
Vol 152 ◽  
pp. 49-51
Author(s):  
P. K. Seidelmann
Keyword(s):  
Time Scales ◽  
Reference System ◽  
Reference Frames ◽  
Optical Observations ◽  
Sidereal Time ◽  
Secular Variations ◽  
Precession Constant

The conversion in 1984 from constants, reference frames, time scales, and ephemerides, all essentially based on theories and constants by Newcomb, to the IAU 1976 system of constants, new definitions of time scales, FK5 reference system, and integrated ephemerides has produced the expected accuracy improvements. These changes included a correction to the precession constant of 1.13 arcseconds per century, a correction to the equinox motion of the FK4 of 1.23 arcseconds per century, and a new expression for the Greenwich Mean Sidereal time.

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