The 38K(p,γ)39Ca reaction is one of the key reactions that govern argon and calcium production in classical novae. Measuring the cross section of this reaction is difficult, though, because 38K is radioactive with a half-life of about 7 minutes. Instead, we can constrain the cross section by measuring the properties of the excited states in 39Ca that govern it. Previously, the energies in those excited states were poorly known. By performing a 40Ca(3He,α)39Ca neutron pick-up measurement led by postdoc Kiana Setoodehnia, we determined the energies and spin-parities of states in the astrophysically important energy region. This lead to a 40% increase in the reaction rate at 100 MK, and will lead to a decrease in the nucleosynthesis uncertainties associated with this reaction.