bluer areas of the HST image clearly have stronger CO absorption than the redder areas above the midplane. The CO line strength is determined by comparing the average depth of the line at rest wavelengths of 22957$\pm$52Å to the continuum measured just to the blue of the CO bandhead [$^{12}$CO (2, 0); @kleinmann86]. We also measured these values for the GNIRS template stars for comparison. The CO line strength values for the NSC range from $\sim$0.10 above and below the major axis typical of late G-type giant stars ($T_{eff} \sim 4800$ K), to $\sim$0.25 along the major axis, typical of K3-K6 giants ($T_{eff} \sim 4100$ K). We caution that the CO depth depends on the gravity of the stars as well as their effective temperature. We note that while Mg, Ca, and Br$\gamma$ absorption are clearly detected in the highest S/N spectra, these features have lower S/N than the CO feature and do not show any obvious variations across the NSC. No emission features are detected.

To better understand the relation between the optical colors and CO line strengths seen within the cluster, in Fig. \[modelfig\] we model these quantities using Padova isochrones which include an updated treatment of the 