NavList:

Frank,

Preliminary note : Many digits given here are not significant and that's acknowledged.

Nonetheless, even with a bit inaccurate ephemeris -  if well under +/- 0.01" for stars mine are only +/- 4" for the Moon - it is worth noticing and it should be recognized that the differences observed in a set of [a bit inaccurate] results generally gain an order of magnitude in accuracy. Hence even from somewhat inaccurate "raw data", we can still derive valid results from their observed trends.

To solve your initial problem, I earlier gave own solutions as :

QUOTE " With refraction : Immersion at 10h57m58.3s   and Emersion at 12h11m34.4s

Without refraction : Immersion at 10h57m58.8s   and Emersion at 12h11m34.1s

The difference between refracted and unrefracted times is just inside my "blind computation time zone", hence I would surmise that refraction did not change anything at all here.

We probably would need Paul's Lunar Software to sort it out.

...///...

Back to refraction, at least in this example, I do not think it changes the Occultation and Emersion times in any appreciable manner. If it ever did, that would most probably be [well] under one second of time." UNQUOTE

I later indicated :

QUOTE " Since my Lunar Distances Program - the one I am using for Occultations too - has a "blind computation zone" of +/- 2 to 3 seconds around the exact time, I have found a different way to very accurately check the effect of refraction / no refraction onto occultations. " UNQUOTE

I then just carried out such more accurate computations with the following results :

(1) - Updated No refraction results are : Immersion at 10h57m58.9s (distances decreasing at a rate of -0.3334"/s of UT time) and Emersion at 12h11m34.4s (distances increasing at a rate of +0.3206"/s of UT time). 

(2) - The effect of refraction on the times of both Immersion and Emersion is under 0.02 s of time.

Also the Parallax induced refraction earlier addressed is under 0.003" in both cases, which is consistent with figure (2) just given.

Pending further confirmation or contradictory information - even more welcome here - from yourself and/or any interested NavList Member on this specific topic which has not raised a lot of interest so far, that is about all I can say to conclude on the [non-]effect of refraction onto stars occultation times by a [Spherical] Moon.

Kermit