120 I. P. Kocu. 
However, in order to gain time for the reading off of the level 
of the axis and to reverse the universal instrument, as well as to 
direct the telescope in the new position of the instrument west of 
the meridian and to make allowance for the change of the right 
ascension of the moon during the observation (the right ascension 
is smallest prior to the culmination), and also for the somewhat 
altered declination of the moon the clock times given must be 
reduced by about 3", whereby about 6" are gained for the second 
position of the instrument. Corresponding to the hour angle 
1 d, + 3”, respectively !/2 d, +3” we must then compute approxi- 
mately: 
for the star: azimuth and zenith distance 
for the moon: zenith distance 
in which manner we become able to bring the instrument into position 
for the observation. 
For the moon it is sufficient when compuling the zenith distance 
to use a mean value of the parallax of about 50. The reduction to 
meridian and the refraction, which partly compensate each other, 
are left out. © being the geographical latitude we consequently get 
z(=e-=00d+50, 
z<=0o--0% and 
5 1 4 
. sin (1/2 d + 3”) cos à * 
STE ES fad 3" ) en 
Sin Z * 
(four-placed). 
When two stars have to be connected with the moon (before 
and after the moon, that is a, * <a €< a, *) the hour angle under 
which the stars are to be observed is approximately 
и SE a) ee the meridian. 
The azimuth is then to be computed from the mean of the 
declinations. 
Before the culmination we thus get the most southerly star and 
after the culmination the most northerly one in the pointed azimuth 
somewhat earlier than indicated by the computed time. 
The carrying out of the observation. M. P. being the 
meridian point of the horizontal circle and Z. P. the zenith point 
of the vertical circle, the horizontal reading becomes in the case of 
the observation east of the meridian М.Р. — ax, while the one west 
of the meridian becomes M.P.—+ ax. According to the position of 
the instrument the vertical circle is placed at Z. P.+ =, where z is the 
zenith distance computed for the object which appears first. Within 
each observation set the azimuth must not be changed. 
