Given that they always have to state the obvious..
Were I to embark on sun-things (here in my sun-angle-limited Valley: I'd ask you first!
And: probably have to get an i-Pad (presuming that that nifty Ephemeris will work just fine sans a cell-fone but with Intarweb.)
Phone essential when going farther than e few miles. Sob.
Can see immediately that no amount of clever notes could possibly nail-it like this App.
HAL is Here! but alas--still mute.
..That's a great Terran sunset, Peter; would you like me to run the light through a few Pbytes of data and get a few Monte-Carlo points?
(I notice you left your ND filter set atop the Refrigerator/helicopter; would you like me to print one out?
--I just had the humans deliver some optical grade plastic to refill that empty Clear-tank. I also have your coffee formula On Tap..)
I can't seem to get the Guinness formula to work at all, though; were I human I'd be mortified.