The invention of the _____________ was considered the critical invention for easily classifying and organizing Stars by brightness, color, and temperature
We use radio telescopes to study naturally occurring radio light from stars, galaxies, black holes, and other astronomical objects. We can also use them to transmit and reflect radio light off of planetary bodies in our solar system.
not a telescope, thats how you see stars. the answer is the HR Chart. If you look at this chart, it has all of the types of stars organized by brightness, color, and temp like the question asks.
