An interesting question! If it's mass you're after, you need to consider that different wavelengths trace different condensations of mass. Here are some example

An interesting question! If it's mass you're after, you need to consider that different wavelengths trace different condensations of mass. Here are some examples that follow the mass of stars in different evolutionary stages: 1) In visible light, you can pretty easily deduce the masses of the stars if you correct for their light shifting to red as it passes through interstellar material. As the star spectra often peak in optical wavelength, the optical image is the "realest" for the star mass 2) When the stars have just been formed, they are still obscured by what we call dust - tiny micron-sized carbon-core particles that are annoyingly good at absorbing optical light. The best tracer for this mass regime would be infrared light, since the dust allows for some transmission. 3) Before the stars are formed, their mass resides in a diffuse (more so than any vacuum in our science labs) yet massive (10^3-10^7 solar masses) molecular clouds. They are typically very cold (~20 K) and their emission peaks at far-infrared light.