STEP 1
Using GMT, and Greenwich date of observation, enter the Nautical Almanac and record tabulated hourly value of GHA and TAB DEC. in your format
STEP 2
At the foot of each declination sub-column, which applies to the sun, a number is found which is used for interpolation for any left over minutes of GMT. This number is called the "d" correction. This is the average over the three day period that the declination changes per hour of GMT. This is a correction, as with any correction, it is either a + or - . If the declination increasing (getting larger), then it is a plus ( + ) correction, if the declination is decreasing, then it is a minus ( - ) ·correction.
Step 3
Turn to the yellow pages of the Nautical Almanac, and find the corresponding minute page,Then find your seconds. Then under the Sun and Planets column find the increase in the sun's GHA since the last tabulated (hourly) value. this is your M&S correction and enter this in your format. Always add the GHA and "m & s" tabulated value together to get the total GHA
Step 4
While on the minute page under the "y" or "d" correction column, find the "d" on the left hand side. Enter this in your format. This will be. the declination (dec) of the sun at the time of sight.
Step 5
Bring down your DR longitude and enter it in your form. The rule is:
LHA = GHA + EAST LONGITUDE LHA = GHA - WEST LONGITUDE.
I will be showing this format in future blogs.
