24 October 2020 11:52 AM Page 5 look something like the figure. Though this is a plot of our data, there are still some calibrations and corrections that have not yet been applied to the data, and can improve our data quality. Let’s look at some of these Photometric calibration of the data Look at the y-axis of your CMD that says Magnitude_2. If we have counted the photons received correctly, this should have the apparent magnitude of our stars in the V (or technically G) band, that is their visual magnitude. What is the range of magnitudes in the plot?What is the typical range of apparent visual magnitude of stars in the sky visible to the naked eye? Are these two ranges consistent? Can you think why they may not be before going on? In Week 5, we discussed the equation which relates the apparent magnitude mV to the flux FV, and in particular (under Week 5 – Multicolour Photometry), the formulae used for different filters is shown. What is the formula relating the V (or G) magnitude to the V (or G) flux?