$V-I$. Indicated against the y-axis of each plot are the emission measure ratios of the hot to cold components that would provide that observed hardness ratio in a simple 2-T coronal model with $T_{1}=0.6$keV and $T_{2}=1.5$keV. The dashed line in the upper plot is a simple straight line fit to the data. []{data-label="hardnessfig"}](hrpnbv.ps "fig:"){width="84mm"} ![The hardness ratio from the pn detector (see section \[hardness\]) for NGC 2547 members versus overall count rate in the pn detector, versus $B-V$ and versus $V-I$. Indicated against the y-axis of each plot are the emission measure ratios of the hot to cold components that would provide that observed hardness ratio in a simple 2-T coronal model with $T_{1}=0.6$keV and $T_{2}=1.5$keV. The dashed line in the upper plot is a simple straight line fit to the data. []{data-label="hardnessfig"}](hrpnvi.ps "fig:"){width="84mm"}

Due to low numbers of counts, spectral fitting barely provides constraints on the temperature distribution of the coronal plasma even in the brightest NGC 2547 sources. Nevertheless, there is sufficient evidence here that these coronae follow the often observed pattern that, given sufficient statistics, a multi-component thermal model fits the data better than a single temperature. To extend our analysis to fainter sources, the hardness ratio, 