Update 14-Apr-18: The verisimilitude of a 13-year orbital cycle bugged me enough that I’ve decided to put Hyperborea in a time warp. I’ve updated this post, with changes noted in blue.
When I was a kid, I really liked the art of Chesley Bonestell. In particular, I loved the pictures of Saturn from its moons:
That’s just awesome.
When I started reading the background info from Astonishing Swordsmen & Sorcerers of Hyperborea, I liked to imagine Saturn/Kyranos huge in the sky, like in Bonestell’s art:
So in my campaign, Hyperborea orbits Kyranos because I think that’s cooler.
Let’s assume that In these latter æons, Kyranos has wandered closer to the Sun/Helios and now has a 13-year orbital period. (This is one Hyperborean “cycle”.) Hyperborea circles Kyranos in a 28-day hour orbit between the moons of Titan and Iapetus. It is situated within a temporal anomaly which operates at about 29× “normal” time. This means that a Hyperborean year is close to a standard Old Earth year.
Instead of AS&SH’s Ganymede, the ruddy planet Ylidiomph (Jupiter) clings closely to Helios. Its orbit has tightened as well, and it shews a 7½-year 147-day cycle. (Astute astronomers have noted Ganymede and the other Galilean moons circling Ylidiomph.)
Likewise, the outer ice giants of Ouranos and Poseidenos have migrated somewhat closer to Helios and can be seen with the naked eye as bluish-green wanderers.
Yuggoth is not visible from Hyperborea, but let’s assume a hypothetical planet matching the recent Planet Nine predictions. (The Mi-Go can confirm details about Yuggoth, if asked.)
Of the interior rocky planets – Mercury, Venus, Earth, and Mars – no trace can be seen.
Out of interest, here’s a somewhat-related article about how Aging Stars Make New Habitable Zones:
The Moons of Kyranos
Saturn/Kyranos has 62 moons with confirmed orbits, 53 of which have names and only 13 of which have diameters larger than 50 kilometers. Seven of these – Mimas, Enceladus, Tethys, Dione, Rhea, Titan, and Iapetus – are large enough to be ellipsoidal in shape. These seven major satellites of Kyranos are clearly visible in the Hyperborean sky.
This means that the AS&SH calendars with Phobos and Selene can’t be used. However, there are now a ton of possible full moon / new moon / conjunction / eclipse possibilities. Hyperborean astrologers are kept busy.
Hyperborean Day Length
While I’m playing with campaign astronomy, I’m also going to enact a 28-hour Hyperborean day.
Why would I do this?
Hyperborean life is strongly influenced by the 13-year orbital cycle. I would like this to be roughly equivalent with “generation” here on Earth, and infants would usually be born in “spring” then grow to have children themselves one cycle later (if they survive the “winter”). However, the idea of 13-year old parents is squicky as hell.
However, given a 28-hour day, Hyperborea’s 364-day year and 13-year “cycle” would be equal to about 15.1 Earth years. Although still squicky, I can accept teen parents of this age in my campaign. And the number 28 is already significant in Hyperborea – 28 hours per day, 28 days per month.
Those who survive into adulthood will usually live to see two or three cycles (equivalent to a life expectancy of 30-45 Earth years). Elders have survived four or more cycles, and the truly ancient may live for six cycles (up to 90 Earth years).