Moon Dust vs Dorn Yellow

How close are they?

ΔE 25.5, loose: different enough that you should pick on purpose. Dorn Yellow is a little darker, much more saturated than Moon Dust.

Can I use Dorn Yellow instead of Moon Dust?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Dorn Yellow is a little darker, much more saturated than Moon Dust.

Can I use Moon Dust instead of Dorn Yellow?

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

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.