HOW BIG
DiscoverNebulae

Nebulae

Cat’s Eye Nebula · shells: size, dimension and comparison

The adopted reference is about 5 light-years.

extent of the envelopes ≈ 5 ly

A light-year is a distance: how far light travels in one year. It is used for distances between stars.

Successive envelopes around a dying star.

Explore at this scale
Cat’s Eye Nebula · shells, interpreted illustration
Interpreted illustration · dimension stated in the fact sheet.
How Big — generated illustration; NASA/ESA documentary references.

What does this number measure?

NASA's Caldwell 6 catalogue describes a nebula spanning about 5 ly. The reference includes the extended shells; it is not just the small bright core shown in close-up photographs.

Compare the stated dimensions

The comparison uses the number in each fact sheet: altitude, height, diameter, length or distance, depending on the reference. Two values in metres do not necessarily describe the same property.

Compare with Horsehead Nebula in the explorer →

Source and limitations

Rounded documentary extent. Boundaries are diffuse and depend on the observations and convention used; this is not a distance from Earth.

Original interpreted scientific illustration, not a photograph. The reference of about 5 ly calibrates the extended envelopes and halo, not the small bright core. The rings depict gas shells seen in projection; the halo's brightness is enhanced for readability. Visualisation colours, details and outlines are interpreted.

Illustration sources

How Big — generated illustration; NASA/ESA documentary references.

Source coverage: Interpreted reconstruction; brightness, colours and textures are not an observation. Only the designated dimension uses the catalogue's representative value.

How Big — generated illustration; NASA/ESA documentary references.

Source coverage: Interpreted reconstruction; brightness, colours and textures are not an observation. Only the designated dimension uses the catalogue's representative value.

How Big — generated illustration; NASA/ESA documentary references.

Source coverage: Interpreted reconstruction; brightness, colours and textures are not an observation. Only the designated dimension uses the catalogue's representative value.