'Tis the season

What would it be like to live on – rather, over – Venus? One notion to start, is how the diurnal and annual cycles would work.

Mars is easy because it’s got a 24:40 hour “sol”; it also has clearly-defined seasons. Venus cloud citizens will likely force its day to be as much like ours as possible – because of the human body’s rhythms. The cities will be subject to the wind, which make one circuit of this planet over four of our days. If drifting with that wind, so to limit the gusts on people working outside, each city will want to force one artificial “day” and one artificial “night” over the four days.

Over the poles and in whatever 30-mile mountains, the inhabitants will be seeing eternal twilight and eternal darkness, respectively. Those can work with artificial day and night, like in space.

The yearly cycle on Venus doesn’t matter for the seasons. There’s another cycle that matters more, especially at first: the Synodic Year, that road shared with Earth. Other routes exist; but all the mainline planetary routes will sync up on the same schedule, and Venus-Earth matters most to Venus. Of the synodic transfers the Hollister Cycler might be how Venus gets passengers. But most important, Hohmann Transfer is how the planets get regular interplanetary trade.

Earth>Mars is on a 25 calendar month synodic cycle. By Hohmann it takes 9 months to get places; overall here's their schedule.

For Earth-to/from-Venus these launch windows occur about every nineteen calendar months (plus maybe five days). Absent any other seasonal markers, Hohmann takeoff from Earth orbit is celebrated on Venus: as I see it, as a "Carnivale" over the next four weeks, before the corresponding Venus caravan takes off back to Earth. OFFSET 11/5/2020: Mostly heavy and fragile objects, with a skeleton crew. Supplies and passengers blast off by shuttle later, say two weeks, meeting the caravan maybe a couple days in microG. AND 11/29: Much depends on which synod of the five in the [eight Earth year] meton; reset [1/9/2021] every circa 245 years. MARS 1/1/2021: In some centuries - like the next one! - there's a Martian angle.

There is, lower-key, also a takeoff from twelve degrees behind the STL5 focus. This station runs a slow orbit in its halo, to match the calendar mooted here. Its main day is 146 days before Venus departure - because some of these travelers are to join Venus', finally to come to Earth. They might even include Terrans from six years ago.

Then follows Conjunction, eight weeks after Hohmann exits Venus. This kicks off an Advent season, of another eight weeks. The next Earth-origin arrival at Venus-orbit after that, is Christmas. Venus' gravity well is wide enough that some will be trickling in a few days before and after the central day itself.

Earth on occasion may send a "Pioneer 12" earlier, to arrive around the same time as the corresponding "P13" meaning, vanilla Hohmann. Those aren't for main freight; they're for orbits.

There are also ranges of dates to get into Venus' long kidneybean Libration orbits. These foci are a sixth of a circle fore and aft so, as part of a synod, 97.3 days. Key here is the Last Chance day, to get out of Venus' gravity-well into its leading L4 (and Earth). Because after that, Earthlings are truly stuck: it's another 389 days before Venus' trailing L5 gets within a Hohmann of Earth. For the spacers, L4->L5 and then L5->L4 do open up in between; so their long wait is "only" a third of the synodic, 195 days.

[METON 11/28/2020] Each synod is not created equal. Earth's orbit is elliptical. Also (Mercury aside) Earth is the planet tilted most against the Sun's equator; Venus the least, at 3.39° between them. Planet-pair synods get grouped by their metonic cycle. For Venus-Earth, it's five. That is the famed Octaeteris on Earth, which - if Venereans cared - would be treiscaedecaeteris over there. This matches the cycle of Hohmann: where materiel not parked first-run, repeats.

DIVISION 1/3/2021: Because each synod per meton is so different, I expect Venereans will be back to thinking like Imperials. Remember £sd? Or stones-and-pounds-and-ounces? Gallons-pints-cups? The natural Venerean long-count, taking the place of decade / year / season (1/10/4), will be meton/synod/quarter: 1/5/4. Shorter "decade"; longer "year" and "season". Above, Venus will observe the Transit Cycle every 243 Earth sidereal years, more Julian than Gregory. That's 30 metons plus a synod, usually two - I expect intercalation will be needed, above that. Below I don't know if they cut the season into three pseudomonths or into four.

BACKDATING 11/15/2019

UPDATE 12/8 - the Maya will love this place.

UPDATE 12/9 - I'm ruling out the Aldrin Cycler for this planet. Back to 1969-70, we go; back to Hollister.