**
The Sky From One Month To The Next**

Before we
proceed, let me define a couple of convenient terms which I shall be using
from now on. The ** zenith** is that point in the sky which is
directly above the observer’s head. The

Also, when
observing you should use ** Local Mean Time**. Local Mean Time is
actually the true time of day of your location as determined by the sun. Time
zones are artificial inventions used to keep large masses of people on the
same time table; therefore, the time you use in your every day life is not the
true time for your location! When you are under Daylight Savings Time you’re
even worse off! Fortunately, finding out your Local Mean Time is a matter of
doing some simple arithmetic. As you will see, there is a little more
arithmetic to do the first time you figure Local Mean Time than there will be
when you figure it later. After the first time there is a short cut that you
can use.

First,
you need to know the longitude of your location to the nearest degree. This
information may be obtained from an atlas or your local library. My favorite
weather forecasting website **www.wunderground.com** gives the latitude and
longitude of any location for which you request a forecast. Find out what
the ** Universal Time** is from CNN International (when they announce
the time, they always give it in Universal Time), from a short wave radio
receiver tuned to station WWV, or from this web site via the Internet:

Divide your longitude by 15. This result is the number of hours that you have to add or subtract from Universal Time to obtain your Local Mean Time. Should your longitude be to the west of Greenwich, England you will subtract. If you are to the east you will add. Example: suppose the longitude of your location is 82 degrees west. Dividing this number by 15 yields 5.47 or approximately 5¾ hours. Say the Universal Time is 1 AM. 1 AM minus 5¾ hours is 7:15 PM. Thus, your Local Mean Time is a quarter past 7 in the evening.

Now to get
the information you need for the shortcut that you will use hence forth! Once
you have determined your Local Mean Time, do the following. Get the “official”
time from your clock. How much later or earlier is your Local Mean Time than
your “official” time? You can use the difference between the two to figure
Local Mean Time from now on! Example: If your “official” time is 7 PM and your
Local Mean Time is 7:30 PM, it means that your Local Mean Time is one half hour
ahead of your official time! Therefore, from now on, you just add one half hour
to your “official time” and you have your local time. IMPORTANT NOTE: If you
did your first time calculation when Daylight Savings Time *WAS* *NOT*
in effect, and you are now under Daylight Savings Time, *subtract* an hour
from your calculated Local Mean Time. If your first time calculation was made
when Daylight Savings time *WAS* in effect and you have switched back to
regular “official” time, *add* an hour to your calculated Local Mean Time.

**copyright 2004 Singularity Scientific, all rights reserved.**

**46**