Final answer:
To measure direct light from a source, astronomers use telescopes, spectrometers, and detectors. Telescopes collect the light, spectrometers sort it by wavelength, and detectors record the observations.
Step-by-step explanation:
Components and Instruments for Measuring Light in Astronomy
To measure light received at a location directly from a source, astronomers use a system with three basic components: a telescope, an instrument that sorts light by wavelength such as a spectrometer, and a detector. The purpose of the telescope is to serve as a light collector, much like a bucket collects rainwater. This telescope gathers visible light or other forms of radiation. The second component, the spectrometer, sorts the incoming radiation by wavelength, allowing finer analysis such as distinguishing individual spectral lines to understand an object's composition or speed. Lastly, the detector—such as a Charge Coupled Device (CCD)—senses and records the observations in the selected wavelength regions. For instance, photographic and electronic detectors are used to capture and measure the color and brightness of astronomical objects after passing through the spectrometer.
Modern telescopes may also use colored filters to separate light into ranges of wavelengths. These filters only transmit light of specific colors and are used for cruder wavelength sorting compared to the detailed separation provided by a spectrometer.