( 387 ) 
Aett. XXVIII . — On a New Method of Calculating the Parah 
laoees for Occultations <fthe Fixed Stars. By M. Charles 
I luMKER, Rector of the Nautical Academy of Hamburgh. 
In a Letter to Dr Brewster. 
Dear Sir, 
In reply to your obliging letter, I take the liberty of commu- 
nicating to you a new method, of my invention, for calculating 
the parallaxes for occultations of fixed stars, and in which neither 
the longitude of the moon nor its augmented semidiameter are 
required. 
Fig. 10. of Plate IX. is an orthograplJi^al projection on the 
plane of the ecliptic, where knh the semidiameter of that circle 
of latitude of the moon which appears to come in contact with 
the star, C the centre of the earth, and A the position of the 
observer on its surface. According to the usual method, we find 
DS =: BD + BS, where BD is the parallax in longitude, for find-^ 
ing from the true place of the moon’s centre, its apparent place, 
and where BS is found with the moon’s augmented semidiameter- 
I find DS=:SE-f-DE, where SE is the parallax in longitude, 
to find from the apparent place of the point of contact on the 
surface of the moon, or star’s place, the true place of that 
ko 
point n of the moon, and where DE = DCE = ^ is found 
with the true semidiameter of the moon. 
Suppose, 
L, Longitude 1 B, True latitude of the ([ ’s centre. 
5, Latitude i / 3 , True latitude of that point of 
X, Longitude the moon behind which the 
H, Altitude 
P , Equatorial parallax. 
SE ■=:%■ — parallax in lon-^ 
star immerges or emerges. 
D, True semidiameter of the (j . 
Apparent zenith distance of 
gitude for the point n. 
the star. 
jp. Parallax in altitude of the 
point n. 
B b 2 
