| SYRTISMAJOR | Dark region of Mars observed by Christiaan Huygens in 1659 as the first documented surface feature of another planet (6,5) |
| TITAN | Largest and first known moon of Saturn, discovered by Dutch astronomer Christiaan Huygens in 1655 (5) |
| REALMS | Regions of Mars the Spanish could have resettled (6) |
| JESSICA | The first documented use of which name is in The Merchant of Venice, used for Shylock's daughter? (7) |
| MESSNER | Italian explorer and mountaineer who made the first documented solo ascent of Everest without supplemental oxygen (7) |
| HERNANDODESOTO | Spanish explorer, the first documented European to cross the Mississippi River |
| DOWNSSYNDROME | Disorder, as it's known in the country of the man who first documented it, caused by the an alterati |
| MARIA | A dark region of considerable extent on the surface of the moon. |
| LANTERN | Case protecting a flame or light bulb; glass chamber at the top of a lighthouse or, linked with "magic" for a device whose invention is credited to Christiaan Huygens (7) |
| CASSINI | Discoverer of the division in the rings of Saturn after whom a space probe (with Huygens) is co-name |
| ELENA | Opera by Francesco Cavalli first performed in Venice in 1659 |
| ALBANYNEWYORK | American city that outlawed golf from its streets in 1659, marking the sport's first official mentio |
| STAHL | Georg Ernst ___, German scientist born in 1659 who developed the phlogiston theory of combustion (5) |
| KORAN | Georg Ernst -, German scientist born in 1659 who developed the phlogiston theory of combustion (5) |
| SATURN | Christiaan Huygens famously observed it |
| MARE | Dark region of the moon |
| NEBULA | Diffuse cloud of particles and gases visible either as a hazy patch of light or an irregular dark region |
| SUNSPOT | Dark region of cooler temperatures and high magnetic fields that appears on our solar system's prima |
| CHEQUES | What bank documents were first issued in 1659 in London? (7) |
| SATURNSRINGS | Major focus of the Cassini-Huygens probe that is due to be destroyed in September, 2017 |
