Chronologically
| Years Largest | Name | Out | In | aperture (m) | Area (m²) | M1 Mirror | Note | Altitude |
|---|---|---|---|---|---|---|---|---|
| 2009–Present | Gran Telescopio Canarias | 10.4 m | 74 m² | 36 x 1.9 m hexagons M1 mirror | Segmented mirror | 2267 m | ||
| 1993–2009 | Keck 1 | 10 m | 76 m2 | 36 x 1.8 m hexagons M1 mirror | Segmented mirror, M1 f/1.75 | 4145 m | ||
| 1976–1993 | BTA-6 | 6 m | 26 m² | 605 cm f/4 M1 mirror | Mirror replaced twice | 2070 m | ||
| 1948–1976 | Hale (200 inch) | 5.1 m | m² | 508 cm f/3.3 M1 mirror | Art deco dome | 1713 m | ||
| 1917–1948 | Hooker (100 inch) | 2.54 m | m² | also used for 1st optical interferometer | 1742 m |
For earlier top telescopes see List of largest optical telescopes historically
Read more about this topic: List Of Largest Optical Reflecting Telescopes