(.).R.A. 0h 1 - 57 - 59
Red. Lo. 5h - 25m 0 - 53
---------------
L.S.T. 3h - 59m - 12s

The reason I am going so much into detail in explaining methods of
finding L.S.T. is because, by a very simple calculation which will be
explained later, we can get our latitude at night if we know the
altitude of Polaris (The North Star) and if we know the L.S.T. at the
time of observation. Some of you may think that the N.A. way is the
simplest. It is given in the N.A., and in an examination it would be
permissible for you to use the N.A. as a guide because, in an
examination, I propose to let you have at hand the same books you would
have in the chart house of a ship. On the other hand, the method given
in the N.A. is not as clear to my mind as the method which starts with
L.M.T., then finds with the Longitude the G.M.T. That gives you, roughly
speaking, the distance in time Greenwich is from the sun. Add to that
the sun's R.A. or the distance in time the sun is from the First Point
of Aries at Greenwich Mean Noon. Add to that the correction for the time
past noon. The result is G.S.T. Now all you have to do is to apply the
longitude correctly to find the L.S.T., just as when you have G.M.T. and
apply the longitude correctly you get L.M.T. That is a method which does
not seem easy to forget, for it depends more upon simple reasoning where
the others, for a beginner, depend more upon memory. However, any of the
three methods is correct and can be used by you. Perhaps the best way is
to work a problem by two of the three that seem easiest. In this way you
can check your figures. When I give you a problem that involves finding
the L.S.T. I do not care how you get the L.S.T. providing it is correct
when you get it.

Assign for Night Reading in Bowditch the following Arts.:
282-283-284-285. Also the following questions:

1. Given the G.M.T. and the longitude in T which is W, what is the
formula for L.S.T.?

2. Given the L.A.T. and longitude in T which is E, what is the formula
for G.S.T.?

3. Given the L.S.T. and longitude in T which is W. Required G.M.T. Etc.

FRIDAY LECTURE

THE NAUTICAL ALMANAC

For the last two days we have been discussing Time--sun time or solar
time and star time or sidereal time. Now let us examine the Nautical
Almanac to see how that time is registered and how we read the various
kinds of time for any instant of the day or night. Befo