Category:Astronomical objects by century of discovery Subcategories This category has the following 7 subcategories, out of 7 total. 0–9 Astronomical objects discovered in the 16th century (4 C) Astronomical objects discovered in the 17th century (12 C) Astronomical objects discovered in the 18th century (42 C) Astronomical objects discovered in the 19th century (82 C) Astronomical objects discovered in the 20th century (101 C) Astronomical objects discovered in the 21st century (26 C)G Galaxies by century of discovery (4 C)
