In this monetary respect only, we would rate the ASTRA IIIB sextant highest, and the Tamaya sextants lowest in value for the metal sextants. The Davis Mark 15 is the best in value for the plastic models.

How accurate is a plastic sextant?

You will see that this instrument can be used with care, and most important with good procedures, to obtain accuracy of some few miles (3 to 5). This is in fact the same accuracy you would get from a metal sextant if not used properly, but with a good metal sextant this can be pushed to 0.5 to 1 mile.

How much do sextants cost?

You can spend anywhere from $19.95 up to $3,000 for a serviceable sextant. The cheapest are made of cardboard (a German-made kit available through Celestaire) and plastic.