FIG. 4.

Comparison of the 24-hour averaged signal for the model (dashed) with the EPOXI data (solid) for the March (upper) and June (lower) dates of observation, demonstrating our fit to the data on an absolute scale. Note that the June observations are overall dimmer than the March observations due to Earth phase. The largest discrepancies are typically in the 450 nm filter and are ∼8% for both observations, within the 10% absolute error in the HRI calibration (Klaasen et al., 2008). The average spectrum of the May observations is similar to that of the June observations (i.e., within a few percent) and was omitted for clarity.