Moon Dust vs Lemon Yellow

How close are they?

ΔE 16.9, loose: different enough that you should pick on purpose. Lemon Yellow is a little darker, much more saturated, cooler than Moon Dust.

Can I use Lemon Yellow instead of Moon Dust?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Lemon Yellow is a little darker, much more saturated, cooler than Moon Dust.

Can I use Moon Dust instead of Lemon Yellow?

The same difference applies the other way round: Moon Dust is a little lighter, much more muted, 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.