  Direct I and V-band imaging of Aql X-1 in quiescence and during outburst
maximum shows that the true optical counterpart is the interloper located 0.48"
West of the previously known star. We find for the new counterpart V = 21.6 and
V-I = 2.2 in quiescence, when its contribution to the total light was 12% in V
and 22% in I. Analysis of this photometry and of low-resolution spectra of the
sum of both stars, also taken during quiescence, shows that the likely spectral
types for the previously known star and the optical counterpart are late G and
late K, respectively, reddened by E(B-V) = 0.5 $\pm$0.1.
