NavList:

Doug,

Excellent !

Did you not notice that - inside the [beautiful carefully crafted wooden] sextant boxes - the eccentricity corrections are most often published in arcseconds and for discrete points, while on the other hand:

- We measure and record Sextants angles as degrees, minutes and tenths of arcminutes,

- We measure and record them on a continous scale.

?

Hence, from my very first years in the "Navies" (French Navy 1972-1980, US NAVY 1980-1983, French Navy again 1983-1987) and since I have kept being a lazy long-haul runner, whenever I knew I would be using a specific sextant for some extended period of time, I would quickly devise and hand-draw a dedicated "continuous" correction curve in tenths of arcminutes.

When I discovered the "irregular entries tables" being used in the US Nautical Almanacs Altitude correction Tables, I quickly reverted to such presentation,

- e.g.

from 0° to 16.44' correction equal to -0.1'

from 16.45' to 22°54' correction equal to 0.0'

from 22°55' to 36°40' correction equal to +0.1'

... this is what I am refering to as "irregular entry table" because entries (or "left columns") are not evenly spaced ... right expression in english ???

Note 1 - If you happen to "encounter" such a hand-written curve, it means that this sextant was being used on-board USS John F. Kennedy (CV-67) between 1980 and 1983 :-)

Note 2 - Lesson learnt : like all too often in Life, Engineers / Designers and Day-to-Day Users are different brands.

Kermit