An Etymological Dictionary of Astronomy and Astrophysics

An area of the sky with relatively low amounts of  → interstellar dust along the → line of sight, occurring toward the  → constellation of  → Sagittarius, near the → globular cluster NGC 6522. The window, through which stars in the → Galactic bulge are visible, lies 3.9 degrees south of the → Galactic center, corresponding to a line of sight that passes within 1,800 → light-years of the → Milky Way’s core. It is named after Walter Baade, who used it to observe → RR Lyrae stars  in the → Galactic bulge region. 

See also: → Baade-Wesselink method; → window.