ΔE 15.3, loose: different enough that you should pick on purpose. Rocket Green is a little darker, much more saturated than Straken Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Rocket Green is a little darker, much more saturated than Straken Green.
The same difference applies the other way round: Straken Green 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.
See Straken Green on the colour wheel See Rocket Green on the colour wheel
All matches: Straken Green equivalents · Rocket Green equivalents