Essay — Celestial mechanics
The long
way around.
On ellipses, patience, and the quiet arithmetic that keeps Tuesday from becoming Thursday.
The long
Plate VIIInner system / true eccentricity
Now observing
The quiet Sun
Fig. 3 — Orbits exaggerated
Essaypp. 12—15
We are taught to draw a circle and then corrected, years later, by an ellipse. The correction is small enough to miss on a school page — a circle pressed gently between two fingers — but it contains the whole difference between a clock and a season.
Kepler did not set out to make the heavens strange. He set out to make them fit. The orbit of Mars refused every perfect arrangement he offered it, and in that refusal was a fact: the planet spends more time far from the Sun than near it. Speed is not constant. Nothing in the sky keeps office hours.
The long way around is not an error. It is the only route that closes.
Imogen Vale writes about instruments, tides and other slow technologies. Her column appears quarterly.
Notes from the plateFig. 3
“An orbit is a negotiation between falling and missing. The planet is always failing, beautifully, at both.”— from the working notebook, 14 September
AlmanacOct 2026
What the sky offers
All times UTC · naked eye unless noted
| 03 | Moon at perigee, 363,412 km | VISIBLE |
| 07 | Draconid meteors, faint | NIGHT |
| 14 | Saturn 1.4° north of the Moon | 21:40 |
| 21 | Orionids, twenty per hour | PEAK |
| 26 | Mercury at greatest elongation | DAWN |
| 31 | Venus enters Libra | — |
Waning gibbous72% illuminated
Moonrise 20:41 · moonset 11:06
Moonrise 20:41 · moonset 11:06
The Almanac is calculated for a small room with one north-facing window. Adjust for your own window.
The Orbital Almanac · Issue 17
“Everything is falling. Some of it is falling with style, in an ellipse.”
p. 17