Chapter 25: Night Sky of Théxar
"When two moons rise over the plains of Kharak, every Xha'Ruun knows: the sky speaks to us. Serrin — full, round, silver — reminds us of the order of the universe. Thel — swift, reddish, uneven — of the chaos from which we were born." — "Astronomy for Everyone," +3,200 Y.E.
Related sections: → see [Ch.24, "Satellites"], → see [Ch.02, "Star System"], → see [Ch.32, "Khar'Vex System"] Key principle: Théxar's night sky — two satellites, five planets visible to the naked eye, 50 constellations. Due to different diurnal cycles (27.3 h) and year (178.2 days), Xha'Ruun astronomy has unique systems of time measurement and navigation.
25.1 Visible Objects
25.1.1 Brightness and Visibility
| Object | App. Mag. | Angular Diameter | Color | When Visible | Phases |
|---|---|---|---|---|---|
| Serrin (full moon) | — | — | Silvery | Night (variable) | Full |
| Thel (full moon) | — | — | Reddish | Night (variable) | Full |
| Khar'Vex (noon) | — | — | Orange | Day | — |
| Vax (max.) | −4.2 | 12″ | White | Morning/evening | 0–100% |
| Xhel (max.) | −2.8 | 8″ | Bluish | Evening | 0–100% |
| Zhal (max.) | +1.5 | 3″ | Yellow | Naked eye under suitable conditions | 0–100% |
| Rhuun (max.) | +4.8 | 1″ | Pale yellow | Naked eye under suitable conditions | — |
25.1.2 Serrin and Thel in the Sky
Serrin is the dominant night object. Its full phase provides illumination of ~0.3 lux (enough for reading). Movement across the sky — from east to west (like other objects, due to Théxar's rotation).
Thel’s brightness and apparent size vary along its orbit.
25.2 Starry Sky
25.2.1 Pole Star
Théxar's rotation axis points toward the star Vokh-Ven ("Truth of Harmony"), the pole star. Located in the constellation El-Ven (Truth). The star is a yellow supergiant of spectral class G5Ib, apparent magnitude +2.1.
25.2.2 Constellations
Xha'Ruun distinguish 28 constellations in the northern hemisphere and 22 in the southern (50 total).
TABLE 25.1: Key Constellations
Constellation Meaning Stars Brightest Visibility Period Vokh-Rass Great Harmony 12 Khar'Vex* Year-round El-Ven Truth 8 Polar (+2.1) Year-round Tor-Ghal Running Beast 15 Alpha (+1.2) Spring–summer Sha-Ruun Speaking People 22 Beta (+0.8) Autumn–winter Khal-Ven Life-Truth 31 Gamma (+1.5) Summer–autumn Mor-Thal Time-Ocean 18 Delta (+2.0) Winter
Khar’Vex is the system’s star. Unlike the distant stars defining a constellation, its apparent position among them changes over the year.
25.2.3 Milky Way
The galaxy is visible from Théxar at an angle — the galactic plane is inclined 42° to the equatorial plane. This provides a better view of the galactic center for the southern hemisphere.
25.3 Planets in the Sky
25.3.1 Vax (inner planet)
Vax is a bright "morning/evening star." Maximum elongation — 38°. Visible ~2.5 hours after sunset or before sunrise.
25.3.2 Xhel
The second inner planet. Visible to the naked eye as a bluish star. Elongation — up to 52°. Visibility period — up to 4 hours.
25.3.3 Zhal
Zhal can be seen without a telescope under a clear sky. A telescope reveals more detail; the planet gradually shifts against the distant stars.
25.4 Astronomical Phenomena
| Phenomenon | Frequency | Duration | Feature |
|---|---|---|---|
| Solar eclipses (Serrin) | — | — | Total, annular |
| Lunar eclipses (Serrin) | — | — | Bright red (H₂S atmosphere) |
| Transits of Vax | ~2/year | 6–10 h | Disk 30″ |
| Transits of Xhel | ~1/2 years | 4–8 h | Disk 20″ |
| Meteor showers | 6 major | 2–5 days | Up to 120 meteors/h |
| Polar aurorae | 8–25/month | 1–4 h | Purple (H₂S) |
25.4.1 Meteor Showers
Largest showers:
| Shower | Parent | Peak | ZHR* | Speed |
|---|---|---|---|---|
| Thalids | Comet Thal-1 | Month Tor-Ven | 120/h | 9.1 мо/s |
| Kharids | Asteroid Khar-52 | Month Khal-Ven | 80/h | 7.1 мо/s |
| Thelids | Thel (dust tail) | Month Mor-Khal | 60/h | 5.7 мо/s |
*ZHR — zenithal hourly rate
25.5 Astronomy in Xha'Ruun Culture
25.5.1 Calendar
Théxar's astronomical cycles formed the basis of the calendar:
- Day: 27.3 hours (rotation)
- Civil month: 29 local days; six months per year.
- Year: 178.2 days (Théxar orbit)
- Year 0 marks the calendar reform; +850 marks the Council of Unity’s foundation.
25.5.2 Navigation
Stellar navigation on Théxar is highly developed. Main methods:
- Altitude of Vokh-Ven (Polaris) — determining latitude
- Position of Khar'Vex at noon — determining longitude
- Phase of Serrin — determining the day of the month
- Astrometric instruments — sextants, astrolabes
Chapter Summary
- Théxar's night sky: two satellites (Serrin, Thel), 5 planets, 50 constellations.
- Pole star: Vokh-Ven (G5Ib, +2.1).
- Eclipses depend on the relative positions of the star, planet and moons.
- Calendar: 27.3 h day, 29-day civil month, 178.2 day year.
- Meteor showers: up to 120 meteors/h (Thalids).