NavList:

You are correct. I wasn't using a sextant or a theodolite.  As I mentioned in my initial post, I was using my phone with Anti Spoof Pro to get simulated sextant altitude data so I could practice sight reductions when it was cloudy outside and no real sextant sights were possible.  As you quoted, I found that Hc for stars and the sun matched the numbers I calculated applying the almanac corrections, but there were differences when I attempted to use moon sights simulated with Anti Spoof Pro.  Many thanks for the explanations you have given me for errors arising from the use of the lunar altitude correction tables.  I am guessing that Anti Spoof Pro creates the expected sextant heights using a more accurate algorithm than simulating a reverse table lookup from the nautical almanac, hence the differences.

Sounds like a theodolite would produce interesting results.  How do you level it to within 0.1 min of arc?

Regards,

Lance