ΔE 8.2, close: similar, with a visible difference side by side. Sky Blue is a little lighter, more muted, cooler than Ray Gun Glow.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Sky Blue is a little lighter, more muted, cooler than Ray Gun Glow.
The same difference applies the other way round: Ray Gun Glow is a little darker, more saturated, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Ray Gun Glow on the colour wheel See Sky Blue on the colour wheel
All matches: Ray Gun Glow equivalents · Sky Blue equivalents