All horizons are not level.
All horizons are not level.
My 4x5 Ebony is allegedly a top-notch wooden folder, but all it took was a little bubble in the varnish to slightly skew the focus plane where the holders seat. Easy fix, but I'm glad I checked. Most of you probably already know that it only took a tiny fleck of paint underneath a calibration device to screw up the first Hubbel telescope mirror - probably the only spot they never checked first.
Well, yes that. Plus there was no third party check of Perkin-Elmer's construction of the Hubble mirror.
https://en.wikipedia.org/wiki/Hubble...nd_engineering
http://www.scienceclarified.com/scit...es/Hubble.html
Ari I bought several of those levels at Lee Valley in Calgary a few years ago
I was directly involved with the folks who made the correction lenses for the Hubbell, but only as a supplier of machine tools and sealants. Prior to that I worked alongside the fellow who machined the Pioneer satellite optics; and he was more interested in recounting NASA shop pranks on co-workers than technical details. I was already good at pranks.
Coming in late here, but I usually rely/use the grid lines on my ground glass when I photograph buildings..works for me..I do not do these multiple pan thingies.
Good luck,
Cor
I am kind of late, but here is a link to very high quality precision bubble levels:
http://www.ehipp.de/EN/index.html
I am not affiliated with them, just using some of their bubble levels on my Arca Swiss
Bookmarks