3) The objects must be; on the chart, clearly identifiable, have a good angle of cut between the resulting position lines and preferably not too far away.

4) Transits.

5) The time the bearing were taken and the distance run on the ship's log.

6) If there is an error in one of the bearings you will get a large cocked hat. Which will indicate that there is a problem, with only 2 bearings there is no indication of the level of error in the fix.