Making CMDs and color-color diagrams

To make a color-magnitude diagram (CMD) or a color-color diagram, you need to (1) convert any fluxes/flux densities you have to magnitudes; (2) compute colors by taking bluer color minus redder color (e.g., B-V or K-[24]); (3) if a CMD, plot magnitudes on the y-axis, with brighter objects (smaller numbers) on the top, so reversing the 'standard' y-axis; (4) if a CMD, colors should be on the x-axis and increase to the right; if a color-color diagram, colors should be on both axes, increasing to the top and right.

Other important CoolWiki pages

• Filters
• Magnitudes
• Photometry (concept)
• Photometry (finding it)
• Color-color and color-magnitude diagrams
• Color selection