[1][citation needed] By amateur standards, a small telescope can have a primary mirror/aperture less than 6–10 inches (150–250 mm) in diameter.
Small telescopes dominate astronomical research in the fields of asteroid/comet discovery/observation, variable star photometry, supernova/nova discovery, and colorimetry/polarimetry of the Solar System's planets.
Because of their limited light-gathering capability, small telescopes are usually not well-suited to spectroscopy, although some useful spectroscopic work can be performed with reflecting telescopes with a primary mirror as small as 14 inches (360 mm) when equipped with the increasingly sophisticated CCD imaging and spectroscopic instrumentation that has become available to amateur astronomers in the 21st century.
Most small telescopes are dedicated to visual observation, although many are used for astrophotography or to gather scientific data.
Even sophisticated designs, such as the Ritchey–Chrétien and (corrected)[clarification needed] Dall–Kirkham, which have traditionally been the preserve of large professional-grade instruments, have become available to amateurs.