NavList:

Greg,

 

 

I reviewed the information that Henry provided as well as my numbers and I think that I am perhaps taking a different path to the same place with the back sight math.  I also checked my hand logs and find Hs to be 101-35.1.  I agree that diagrams are very helpful to try and figure this stuff out.

 

We are lucky here because the observation is a planet so we don't have to worry about semi-diameter unlike the sun.  All of my other backsights have been either of the sun or moon and I seem to remember always observing the true lower limb (it appeared to be an upper limb in the scope) to minimize the complexity of the reduction.

 

I made this "form" from the Bowditch 1984 article.

 

In this case, I will run down my methods so that we can compare notes:

 

-IC   +0.8  (IE is 0.8' on the arc as usual)

-Dip +9.6

-------------

Corr     +10.4

Hsc 78 - 24.9   (180d - 101d 35.1') complement of the sextant reading

--------------------

Hs 78d 35.3'

Body     -0.2'

Body'     0.0'  (body is too high and therefore outside of the range of the 2nd correction)

-------------------

Hs 78d 35.1'

 

Zd = 11d 24.9'

 

Dec = S18d 41.1' (Dec and Lat same name, body closer to pole than position)

-ZD       11d 24.9'

----------------------------

Lat        07d 16.2' S