đ Key Concepts
⢠Adjustable sextant errors vs. nonadjustable (permanent) errors
⢠How side error and index error are normally corrected by the navigator
⢠Which parts of the sextant the navigator can physically adjust during a preâsight check
đ Think About
⢠First separate in your mind: which errors can you fix yourself with the sextantâs adjustment screws, and which require a repair shop or manufacturer attention?
⢠Think about which components (mirrors, telescope, frame/arc) you routinely touch and line up during the âsextant on the dockâ checks before taking sights.
⢠For each choice, ask: is this something I would normally clear by sighting a star, horizon, or checking on a vertical object, or is it âbuilt intoâ the metalwork and not user-adjustable?
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Before You Answer
⢠Identify which listed errors are normally corrected by adjusting the index mirror, horizon mirror, or telescope.
⢠Recall which error is due to the arc or frame not being perfectly shaped or centered, and whether a user can practically fix that at sea.
⢠Before picking, cross out any error you remember routinely clearing during a standard sextant adjustment procedure (index, side, and collimation checks).