What is being measured?
NASA's approximate diameter across the primary mirror. This is a linear span, not the collecting area or a single mirror segment's size.
Use the named object, variant and dimension. A manufactured or natural object can differ from this reference.
- Dimension
- primary-mirror diameter
- Reference value
- 6.5 m
- Evidence
- Published reference measurement
- In metres
- 6.5 m
- Variant
- Deployed primary-mirror assembly
Put the length in perspective
One James Webb Space Telescope primary mirror represents approximately 75.9 card lengths measured end to end. This is a length ratio; it does not calculate how the objects pack or fit.
James Webb Space Telescope primary mirror · 6.5 m
Metre · 1 m
Foot (international) · 0.3048 m