NavList:

Thanks, Robin.

Here’s a modified segment of the explanation at http://fer3.com/arc/m2.aspx/Lunars-how-use-proplog-tables-EdPopko-aug-2016-g36381

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Using your post data ...

12:00 UT, 84° 35'.2, PL 2620

pLogD =   2620

and ...

d is total change in LD distance from First time (12:00) to your unknown time of lunar sight
d = 84° 35.2' - 83° 00.0'
  = 1 35.2'
Looking 1 35.2' up in table ...
pLogd = 2766

Thus ...

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The difference between 2623 calculated directly and 2620 from the Almanac propagates through and changes the final result slightly

I'm sure Ed was right about the value of plog D.

D is NOT from the Almanac, it should be calculated as a "width" between the tabulated brackets:

84° 35.2' - 82° 56.8' = 1° 38.4'

because D is the whole change of the lunar distance (that will happen during the full 3 hours between the brackets) from which we need to find a part corresponding to the actual change that happened since the first tabulated bracket.

So plog D = plog(1° 38.4') = 2623.

Further is just my nitpicking: because the resulting plog t = 143 is two-thirds closer to the tabulated value of 142 than to 145 I must interpolate the time t two-thirds closer to 02:54:12 from 02:54:06, and rather than picking the middle of the interval (i.e. 02:54:09) I must take it as 02:54:10.

The final value of UTC of the lunar must be 14:54:10.

Please comment.

Regards,

Tony