Limb to use- Upper or Lower?

[EdCa]

Old thread but here's my opinion.
I use an AH and prefer to superimpose the images, partly because then I don't have to do the u/l limb corrections, partly because I can never remember which is upper or lower with the AH and partly, as has been mentioned to 'average' out the effect of the rippling of the water, lol.

That's a good idea, BigBill.  Using the same method I only correct for Refraction and IE but never parallax as it's too small to make much difference.

Making an AH that's covered is pretty simple.   CelNav57 made one-

Here-  Artificial Horizon

I had one made by Davis Instruments made of plastic.  It's rather junky and a nuisance too work with.



Ed