of the New Berlin Astronomical Ephemeris. 249 



hours of the forenoon of the civil day following the one cor- 

 responding to the given hours of the astronomical day. All 

 longitudes, latitudes, right ascensions and declinations, refer 

 to the true or apparent equinox, and the true or apparent po- 

 sition of the different planets, for which Mr. Bessel's determina- 

 tions of the nutation and obliquity of the ecliptic have been 

 throughout applied. All data have been calculated from the 

 tables without neglecting any one correction, and have been 

 given exactly as resulting from the tables. A main object of 

 these ephemerides has been to save to the astronomer the 

 trouble of the tedious immediate calculations from the tables. 



The almanac contains, besides the chronological part and 

 the explanation of the signs, four principal sections; viz. 

 1. Ephemerides of the sun and moon. 2. Ephemerides of the 

 planets and their satellites. 3. Positions of the stars. 4. Phe- 

 nomena and objects of observations. 



For the sun and the moon every month has six pages, which 

 for the facility of reference have been separately marked with 

 Roman figures, I — VI. The first page contains the data neces- 

 sary in solar observations. Their epoch is, therefore, the ap- 

 parent noon at Berlin. After the first two columns, the days 

 of the month and of the week, follows the mean time at the 

 moment of the apparent noon, usually called the equation of 

 time ; next, the right ascension of the sun, or the sidereal time 

 at the apparent noon ; then the declination accompanied by 

 the column, log. \t* (agreeably to Gauss's notation, in the manner 

 of Professor Schumacher's auxiliary tables), which is the log. 

 of the change of declination in 48 hours expressed in seconds 

 of a degree from the preceding noon to the following one, or 

 very nearly the change of declination for 48 hours appertain- 

 ing to the noon opposite to which it stands in the ephemeris. 

 Lastly, the sidereal time is given which the sun employs in 

 passing over the wire of a transit. The opposite page II. con- 

 tains the data for the sun which are employed in calculations 

 of the planets. Their epoch is, therefore, the mean noon. The 

 columns of days of the month and of the week are followed 

 by the sidereal time at the moment of the mean noon, which is 

 requisite for reducing an observation made by sidereal time to 

 mean time. Next follow the longitude, latitude and radius 

 vector of the sun. In the former, the aberration has not been 

 applied, so that the given numbers must be immediately used, 

 without any correction, in converting geocentric places into 

 heliocentric ones, and vice versa. Lastly, the semidiameter of 

 the sun is given, which is used in observations of declination. 



These data have been derived from the solar tables of Car- 

 lini, improved by Mr. Bessel's corrections, which he has had the 



New Series. Vol.4. No. 22. Oct. 1828. 2 K kindness 



