moonphasecalendar.com
Moonstick Co. - manual visual calculators for astronomy, timekeeping, and computation
http://www.moonphasecalendar.com/index.htm
About the Moonstick Co. Moonstick Co. History. The Moonstick Co. was founded in September of 1997 with the invention of our flagship product, the moonstick. A slide rule that could calculate moon phases. You can see the original patent. Here The original moonsticks were made of paper and sold outside of planetarium shows during the late 1990's for $5. New Product Showcase. See a scan of the page here. Other products followed, the 4000 year perpetual calendar. Which was later featured in Sky and Telescope.
chordboard.webstarts.com
chordboard
http://chordboard.webstarts.com/de.html
Entworfen von Martin H. Samuel. Entwickelt für iOS von Pierre Bernard, 2011 Houdah Software s.à r.l . Akkorde bestehen aus 3 oder mehr Noten einer Tonleiter. Die Chord Board iPhone / iPod Touch App. kann als elektronischer Tuner für die Gitarre, Banjo, Ukulele oder Bass verwendet werden. Die sechste Note jeder Dur-Tonleiter ist der erste [Grund]-Ton der entsprechenden. Benützen Sie die obere Zeile für Dur-Akkorde, die untere Zeile für Moll-Akkorde. In die transponierte Hauptposition gegenüber von 1.
stevenjohnson.com
Cardboard Calculators, Slide Charts and Wheel Charts for Electronics and Technology
http://www.stevenjohnson.com/cardboard/index.html
Slide Charts, and Wheel Charts. Electronic, Radio, and Technology Related. Cardboard Calculators, Slide Charts, and Wheel Charts. Before electronic calculators and desktop computers there were cardboard calculators and indicators. Some were sold or given to engineers as engineering tools and others were given away as business cards or promotions. A few more modern electronic calculators. Things I've collected that really don't fit in the categories above but I find interesting. Could be anything incl...