Friday, January 18, 2008


STEP 1 Using GMT, and Greenwich date of observation, enter Nautical Almanac and record tabulated hourly value of GHA ^

STEP 2 Turn to the yellow pages of the Nautical Almanac, and find the "22 minute page," enter with "28-seconds."

Then under the "ARIES" column find the increase in the GHA ^ since the last tabulated (hourly) value, hence 5° 37.9'.

This is your minutes and seconds (M&S) correction and enter this in your format.

STEP 3 Add the GHA and M&S to get the GHA^

STEP 4 Bring down your DR longitude and enter it in your form, the rule is:



So we add our DR longitude to get the LHA ^

STEP 5 To use the star finder, select the blue template nearest your DR latitude, hence 25° S and place it on the South side of the white star finder. You should have the South side of the blue template matched up with the South side of the white star finder.

Remember to ensure that the proper side of the template is up, hence, north to north south to south.

STEP 6 Rotate the blue template until the 0° to 180° arrow on the template is over the LHA ^ of 52° on the base plate.

The stars or planets that are available to you at that time, will be under the grid system of your blue template.

STEP 7 Locate the bearing of 029° T on the inner edge of the grid.

STEP 8 Using the Ho as the approximate altitude 30° go up to the bearing of 029° to altitude 30° and you will find the unknown star "ELNATH".

After identifying the star, you would have to work out the sight by starting over again on the form.

This problem goes with the "UNKNOWN STAR FORMAT".