ΔE 29.6, loose: different enough that you should pick on purpose. Altdorf Guard Blue is noticeably darker, much more muted than Pale Blue Dot.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Altdorf Guard Blue is noticeably darker, much more muted than Pale Blue Dot.
The same difference applies the other way round: Pale Blue Dot is noticeably lighter, much more saturated.
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 Pale Blue Dot on the colour wheel See Altdorf Guard Blue on the colour wheel
All matches: Pale Blue Dot equivalents · Altdorf Guard Blue equivalents