Astrophysics & Particle Physics-APPC 2026

Observational Astronomy is the discipline of astrophysics that entails direct observation of celestial bodies and phenomena using telescopes, detectors, and other astronomical equipment. It contributes the empirical basis for the understanding of the universe, supplementing theoretical and computational methods.Observational astronomers apply photometry for the measurement of the luminosity of stars and galaxies, and spectroscopy to study their composition, temperature, motion, and magnetic fields. Imaging methods at various wavelengths—ranging from radio, infrared, optical, ultraviolet, X-ray, to gamma-ray—allow investigation of various astrophysical events like star formation, supernovae, black holes, and galaxy evolution.Ground observatories with big optical and radio telescopes, and space observatories such as Hubble, Chandra, and James Webb Space Telescope, provide astronomers with the means to peer into the universe free from the distortions of Earth's atmosphere. High-resolution imaging, adaptive optics, and interferometry have transformed observational capability to allow for high-resolution mapping of stars, exoplanets, and galaxies far away. Surveying the sky, compiling catalogs of stars, galaxies, quasars, and transients like supernovae and gamma-ray bursts is also part of observational astronomy.

Such surveys yield statistical information vital for examining theories of cosmology, stellar evolution, and galaxy formation. Observations of exoplanets, pulsars, and variable stars also help to understand dynamic phenomena in the universe.Data acquired by observational astronomy is then processed using sophisticated computational algorithms, simulation, and modeling so that astronomers can derive physical characteristics and understand intricate phenomena.

Multi-messenger and multi-wavelength observations involving gravitational waves and neutrinos have broadened the discipline, giving astronomers a broader understanding of the universe.By linking theory to precise measurements, observational astronomy continues to be a foundation of astrophysics today, enabling scientists to study the structure, makeup, and evolution of the universe, and uncover phenomena invisible to the human eye.