Re: ... and daytime polar alignment
Have a look at my DYI Bubble Level in this group’s FILES section – Because the bubble’s travel is a “foot long”, it is far more precise than my STARRETT. The “pipette” is already marked out with fine millimetre divisions by design, since it is already precisely marked for measuring “millilitres” in the lab. That’s “lab accuracy” as good as for a machinist’s use.
It also cost me about $2 (for a used pipette – they are disposable, easier to find), compared to a Starrett costing over a hundred (?) dollars, and is far easier to read a large bubble on a long path. Because it has so much more fluid, the bubble starts to travel at just a hare’s breath of a tilt, compared to the smaller tube in a machinist’s level. Besides, the pipette is Plexiglas, or tempered glass, (lab use safety concern), so it won’t break when dropped or banged in travel, as my old STARRETT glass tube did.
you can fill the pipette bubble level with turpentine, radiator cold weather antifreeze, or with (coloured) winter windshield wiper fluid, for outdoor cold temperature use. You can even add an LED lighting to the tube top or ends for easier night use.
See PDF article and photos: DIY BUBBLE LEVEL TOOL.pdf ( ASTROJAZ - Jan 31, 2016)