Guide to the Uninitiated,or What you need to know about Pern
Pern is an Earthlike planet a long way away from here. Its solar system includes a rogue planet, known as the Red Star, which strips alien spores from the system's Oort Cloud and drags them to the inner system, where they "germinate" during transit through the upper atmosphere and fall onto Pern as Threads (think of them as luminous ropes of nitric acid) which eats through any organic matter unless killed by fire, water, or extreme cold. Each Threadfall lasts about six hours, over a band about 20 x 300 km of the surface, and a Pass of Thread lasts fifty years. There is an interval of about two hundred years between Passes.
Fifteen hundred years before our story starts, Pern was colonised by people wanting to return to a relatively simple life. They settled initially on the lush southern continent, but were forced to move to the rocky northern continent to escape earthquakes, volcanos and Thread. A brilliant genetic engineer modified a native lifeform (fire-dragonet) into a large dragon, capable of projecting flame. Both native and modified dragons had the ability of teleportation (going between), which allows them to escape Thread and also to kill any Thread that might have landed on them. Dragons don't speak, but they communicate freely among themselves through telepathy. There is a similar link between each dragon and his or her bonded rider, which starts at Impression and lasts until death.
Pern society is now organised into Weyrs (housing the dragons and support staff) and Holds (housing the farmers and craftsmen). There are six Weyrs to cover the whole of the northern continent (from West to East: High Reaches, Fort, Telgar, Ista, Igen and Benden). There are 15 major Holds, headed by Lords Holder, and a large number of smaller Holds and crofts. Each Hold looks to a Weyr for protection during Threadfall, and tithes a significant percentage of its produce to support the Weyr, since riders don't have the time or the land to cultivate food. Crafts are like the medieval guilds, with apprentices, journeymen and masters. Although craftsmen live in Holds, they answer to the head of their craft rather than the Holder. Most crafts have a cental Crafthall collocated with one of the senior holds - for example, Fort Hold has the Harperhall and the Healerhall - where teaching and research are done. Harpers play a significant role in Pern society - they're not just entertainers, but they teach and carry news as well, and make sure that the Holds maintain respect for the Weyrs.
The rank of each dragonrider and craftsman can be told from a set of knots worn at the right shoulder. The system of knots as described in DGP (p 65 & 115) is impractical - there are not enough combinations of colours and styles to distinguish the various riders and craftsmen. The diagrams themselves are not coloured or clearly labelled for colour, and in some cases are mis-labelled (the first "wingleader" should in fact be "Weyrleader/Weyrwoman"). Unfortunately, the knots are not described in sufficient detail in the novels to resolve the discrepancies. Furthermore, the craft knot descriptions given in DGP do not match the portraits in POP, where Masterhealer Oldive and Masterharper Robinton are shown with a simple double twist of cord (not ribbon) in the craft colour. For the purposes of this story, therefore, I have included in Weyr knots a black cord denoting "Weyr" and in Craft knots a white cord denoting "Craft". The second cord identifies which Weyr or Craft, and for riders, the third, thinner cord identifies the colour of their dragon. Holders do not wear knots; they show their hold affiliation in badges or trims.
Children may be brought up by their parents, but most dragonriders' children (weyrbrats) and many Holders' children are fostered out for all or part of their lives. Much care is taken to ensure that fosterlings and foster-parents are well-matched and that the children's talents are spotted and nurtured. Although many dragonriders' sons become riders in their turn, Impression is not guaranteed, so each child must start learning a craft or trade when they finish formal schooling at around 14. The Impressionable age range is generally given as 12-20 Turns, though exceptions have been known.
Each Weyr houses approximately 500 dragons and their riders, and 1500 other staff, including cooks, drudges, craftsmen, children and elderly. Dragons and riders live in caves (weyrs) cut into the rockface, often only accessible on dragonback; while everyone else lives in the lower caverns. Weyrlings (trainee riders) and their dragonets are housed in a weyrling barracks until their dragons are capable of flying up to the rim. Once trained, dragons are organised into six to twelve fighting wings of 30-90 dragons, each wing a mix of colours.
Dragons come in five colours:
a. Gold (queens) - about 40m long, female and fertile. They mate with bronzes (and occasionally browns). The senior queen's rider (invariably a female heterosexual) is the Weyrwoman, and the rider of the bronze who mates with her is the Weyrleader.
b. Bronze - about 35m long, male. They are the strongest and can project flame the furthest, but they are not as agile as the smaller dragons. Their riders (invariably male heterosexual) are the wingleaders.
c. Brown - about 30m long, male. They are less strong than the bronzes, but still much stronger than the smaller dragons. Their riders (invariably male heterosexual) are often wingseconds and instructors.
d. Blue - about 25m long, male. They are described as the "foot soldiers" of the wing - strong enough to flame a distance, agile enough to avoid injury. Their riders (always male) are often gay, but some can be straight or bisexual.
e. Green - about 20m long, female. They are the smallest and most agile, but not as strong as the larger dragons, and have a short flame projection. They are rotated during a long fall to avoid fatigue. They are affectionate and flirtatious, and will mate often with blues and browns, but are infertile. Their riders (originally intended to be female but now always male) are invariably gay, and often effeminate, but nonetheless courageous.
The calendar of Pern is divided into 13 months of 28 days each, with two additional days called Turn's End and Turn's Beginning (the winter solstice), making 366 days in total. Summer solstice is the 15th day of the 7th month. For everyday purposes, years are numbered since the start of the Present Pass (or Interval). [NB - AMcC didn't adopt this calendar until later in the series - early books feature a 365-day Gregorian calendar]
Pern has an axial tilt of only 15 degrees, meaning that the tropics and arctic circles are much smaller, and the variability of sunrise and sunset through the seasons is smaller. Fort Weyr, being about 30 North of the equator, would have approximately 15 hours of sunshine at midsummer and 9 at midwinter. At the summer solstice sunrise would be about 0430 and sunset about 1930, while at the winter solstice sunrise would be about 0730 and sunset about 1630. There would not be much in the way of twilight.