The Observatory
Unique Astronomy Instruments
Every calculator on this site does one job well. These do something different: each one is a one-of-a-kind instrument, built once, that turns real calculated sky data into something you can watch move, read from, or print and keep. This page is the map to all of them.
Methodology
Real astronomical data, checked twice
Every position these instruments show — planets, the Moon, sunrise and sunset, conjunctions — comes from Astronomy Engine by Don Cross, the same open-source engine used across CalculationTime’s astronomy pages. We cross-check the results against Jean Meeus’s Astronomical Algorithms, the standard reference text professional ephemeris software is built from, before an instrument is published here.
What that means in practice
Design is ours, positions are not
- The astronomical calculations come from Astronomy Engine, not a guess or an illustration.
- Results are cross-verified against Meeus’s Astronomical Algorithms before publication.
- The visual design, dial layout and print outputs are CalculationTime’s own work.
- Each instrument states its own limitations rather than presenting itself as a professional ephemeris.