g
star time and apply them with the information we now have from the
Nautical Almanac. If the G.M.T. on April 20th is 4h--16m--30s, what is
the G.S.T. for the same moment? That is, when Greenwich is 4h--16m--30s
from the sun, how far is Greenwich from the First Point of Aries? You
remember the formula was G.S.T. = G.M.T. + (.).R.A. + (+).C.P.

G.M.T. 4h--16m--30s
(.).R.A. 1 --50 -- 6
(+).C.P. 0--42
--------------
G.S.T. 6h--07m--18s

Suppose you were in Lo. 74 deg. W. What would be the R.A.M. (L.S.T.)? You
remember the formula for L.S.T. from G.S.T. was the same relatively as
L.M.T. from G.M.T., i.e.,

L.S.T. = G.S.T. - W. Lo.
+ E. Lo,

Here it would be

G.S.T. 6h--07m--18s
(74 deg. W) - 4 --56 --00
---------------
L.S.T. 1h--11m--18s

Now these are not a collection of abstruse formulas that you are
learning just for the sake of practice. They are used every clear night
on board ship, or should be, and are just as vital to know as time by
the sun.

Suppose you are at sea in Lo. 70 deg. W and your CT is October 20th
6h--4m--30s A.M., CC 2m--30s fast. You wish to get the R.A. of your M,
i.e., the L.S.T. How would you go about it? The first thing to do would
be to get your G.M.T. It is CT--CC.

20d--06h--04m--30s A.M.
--12
------------------
CT 19d--18h--04m--30s
CC --02 --30
------------------
G.M.T. 19d--18h--02m--00s

Then get your G.S.T.

Oct. 19d--18h--02m--00s
(.).R.A. 13 --47 --38.5
(+).C.P 2 --57.7
--------------------
19d--31h--52m--36.2s
--24
--------------------
G.S.T. 19d-- 7h--52m--36.2s

Then get your L.S.T.

G.S.T. 7h--52m--36.2s
W.Lo (--) 4 --40
--------------
L.S.T. 3h--12m--36.2s

The last fact to know at this time about the Almanac is found on pages
94-95. Here is given a list of the brighter stars with their positions
respectively in the heavens, i.e., their celestial longitude or R.A. on
page 94 and their celestial latitude or declination on page 95. These
stars have very little apparent motion. They are practically fixed.
Hence, their position in the heavens is almost the same from January to
December though, o