Sextant

Question 1

List the fixed errors of a sextant

(4)

Answer 1

• Graduation error

• Collimnation error

• Centering error

• Optical error

Question 2

List the adjustable errors of a sextant.

(3)

Answer 2

1. Perpendicularity Error
   Index mirror not perpendicular to plane
2. Side Error
   Side (Horizon) mirror not perpendicular to plane
3. Index Error
   Index mirror and Side mirror are not parallel

Question 3

What is the “merpass” short for?

When must a Merpass be done?

Answer 3

Meridian Passage

At noon when the sun is at it’s highest point.

Question 4

How can longitude be calculated?

Answer 4

The time difference between Merpass @ London to Merpass at our location knowing that 15• = 1hr and 1• = 4mins.