astropy

# Astropy ## Overview Astropy is the core Python package for astronomy, providing essential functionality for astronomical research and data analysis. Use astropy for coordinate transformations, unit and quantity calculations, FITS file operations, cosmological calculations, precise time handling, tabular data manipulation, and astronomical image processing. ## When to Use This Skill Use astropy when tasks involve: - Converting between celestial coordinate systems (ICRS, Galactic, FK5, AltAz, etc.) - Working with physical units and quantities (converting Jy to mJy, parsecs to km, etc.) - Reading, writing, or manipulating FITS files (images or tables) - Cosmological calculations (luminosity distance, lookback time, Hubble parameter) - Precise time handling with different time scales (UTC, TAI, TT, TDB) and formats (JD, MJD, ISO) - Table operations (reading catalogs, cross-matching, filtering, joining) - WCS transformations between pixel and world coordinates - Astronomical constants and calculations ## Quick Start ```python import astropy.units as u from astropy.coordinates import SkyCoord from astropy.time import Time from astropy.io import fits from astropy.table import Table from astropy.cosmology import Planck18 # Units and quantities distance = 100 * u.pc distance_km = distance.to(u.km) # Coordinates coord = SkyCoord(ra=10.5*u.degree, dec=41.2*u.degree, frame='icrs') coord_galactic = coord.galactic # Time t = Time('2023-01-15 12:30:00') jd = t.jd # Julian Date ...