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Guides: the science behind what you see
Explore measured distances and scale, or prepare for outdoor observing with independent telescope and binocular guidance. Each guide is useful on its own, without loading the 3D view.
Measured facts
- Distance guides
- Earth–Mars and Earth–Moon, both with measured extremes and dates
- Scale guide
- A ladder from 180 km altitude to the 20 kpc model boundary
- Catalogue guides
- Nearby stars and the Galilean moons
- Method
- Every figure is computed from COSMOS archives, not quoted from memory
Why these guides exist
An interactive 3D map is a poor way to receive a number: you cannot copy a distance out of a camera flight. Each guide takes one question, answers it in text with the measured value, states the archive and the method behind it, and then offers the explorer as the next step rather than as a prerequisite.
How to read the numbers
- Distances that change with time are given as a range plus the dates of the extremes, never as a single figure.
- Anything derived from parallax reports the parallax it came from.
- Anything interpolated reports the archive window and is never extrapolated past it.
- Model quantities are labelled as model quantities on the page that shows them.
Content updated 2026-09-26. Every value on this page is computed from the shipped datasets; where a source publishes no value, the page says so instead of estimating one.