# The Demystified Astro Navigation Course Unit 2 Self Test

## Unit 2 Self Test

Question 1.

Position: 38o 15’N. 30o 38’.3 W,

GHA Sirius: 150o 15’.4.

What is the LHA?

Question 2.

Position:  33o 12’.8S.  70o 54’.5E,

GHA Sun: 45o 23’.4

What is the LHA?

Question 3.

Position:  52o 42’.45N.  65o 19’.67E

GHA Moon:  345o 15’.0

What is the LHA?

Question 4.

Position:  34o 28’.45S.   172o 25’.8W.

GHA Mars:  15o 30’.0

What is the LHA?

Solutions

Q.1.

Long West,   LHA = GHA – LONG

GHA   = 150o 15’.4

LONG =  30o 38’.3W     (-)

LHA   =  119o 37’.1

Q.2.

Long East, LHA = GHA + LONG

GHA    =  45o  23’.4

LONG  =  70o  54’.5E    (+)

LHA    = 116o   17’.9

Q.3.

Long East, LHA = GHA + LONG (-360o ?)

GHA   = 345o  15’.00

LONG =   65o  19’.67E.  (+)

LHA   =  410o 34’.67

360o 00’.00    (-)

50o 34’.67

Q.4.

Long West, LHA = GHA – LONG (+360o ?)

GHA   =      15o  30’.0

LONG =   –172o 25’.8W.  (-)

LHA    =  -156o  55’.8

+360o  00’.0      (+)

203o   04’.2

Note.  The calculations can be made simpler by converting minutes to fractions of a degree as follows:

To convert minutes to fractions of a degree, divide by 60.

To convert fractions of a degree to minutes, multiply by 60.

The solution to Q.4 now becomes:

GHA   =        15o.5

LONG =     –172o.43 W.  (-)

LHA    =     -156o.93

+360o. 00       (+)

203o. 07

LHA  =     203o  04’.2