David: Thanks! I'll stay tuned for more.
Parks: No argument implied, just a question! It does seem odd to me that this varies just as a *general* observation. (But, of course, that's why I put that "big" in quotes -- it's not really ALL that big, but it is interesting and potentially significant at higher values.) Was I quibbling?? My question really didn't have anything to do specifically with Californian.
As for what difference it might make, well, it *could* be a typo. MANMAR's formula, reproduced at the web site I mentioned, didn't include the square root portion until I pointed out that omission. Likewise, David's "6076 ft." led me to realize that my own edition of "Pocket Ref" contains an error. Rather than 6076.1, it claims "6067.1"! And I do kind of like to get these things straight myself. ;^)
Anyway, I've since seen a copy of "Norrie's" tables which appear to use a factor around 1.155. So we have thus far 1.14, 1.144, 1.15, 1.155, 1.169, and 1.17, none of which I've in any way "fingered" for veracity. But since I did notice it, I thought I'd ask. If anything, I'm as interested in whether any of these formulae purport slightly different results based on "average" versus "perfect" viewing conditions, etc.
S'alright?
John