Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Andromeda Galaxy: 01-05 (100), 01-06 (100), 01-07 (100), 01-08 (100), 01-09 (100) — by astronomy; check the weather when the night is within four days.

2025-12-27astronomy score per night — click a bar for that night2026-01-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2025-12-27 Sat	70	100	70	18:40–00:25 (good, 5.75 h)	89.7° 18:40	11.49	51%	36.1°
2025-12-28 Sun	53	63	33	19:00–22:00 (marginal, 3.0 h)	89.7° 18:35	11.48	62%	30.5°
2025-12-29 Mon	34	100	34	18:40–00:55 (marginal, 6.25 h)	89.6° 18:30	11.48	73%	30.2°
2025-12-30 Tue	27	25	7	18:40–20:00 (marginal, 1.33 h)	89.5° 18:30	11.47	83%	35.7°
2025-12-31 Wed	27	40	11	18:45–20:00 (marginal, 1.25 h)	89.6° 18:25	11.46	91%	45.2°
2026-01-01 Thu	34	100	34	18:45–00:15 (marginal, 5.5 h)	89.7° 18:20	11.45	97%	56.7°
2026-01-02 Fri	49	83	41	18:45–23:00 (marginal, 4.25 h)	89.7° 18:15	11.44	100%	69.1°
2026-01-03 Sat	68	0	0	—	89.5° 18:10	11.43	100%	81.9°
2026-01-04 Sun	82	0	0	—	89.5° 18:10	11.42	97%	94.5°
2026-01-05 Mon	100	0	0	—	89.7° 18:05	11.4	92%	106.8°
2026-01-06 Tue	100	0	0	—	89.7° 18:00	11.39	84%	118.4°
2026-01-07 Wed	100	0	0	—	89.6° 17:55	11.37	76%	129.1°
2026-01-08 Thu	100	39	39	23:00–23:45 (good, 0.75 h)	89.5° 17:50	11.36	67%	138.4°
2026-01-09 Fri	100	53	53	21:00–22:55 (good, 1.92 h)	89.6° 17:50	11.34	57%	145.8°
2026-01-10 Sat	100	32	32	21:00–22:00 (good, 1.0 h)	89.7° 17:45	11.32	47%	149.9°
2026-01-11 Sun	100	0	0	—	89.7° 17:40	11.31	38%	150.0°
2026-01-12 Mon	100	95	95	19:00–23:45 (good, 4.75 h)	89.6° 17:35	11.29	29%	146.0°
2026-01-13 Tue	100	6	6	23:00–23:25 (marginal, 0.42 h)	89.5° 17:35	11.27	21%	139.2°
2026-01-14 Wed	100	99	99	18:55–23:35 (good, 4.67 h)	89.6° 17:30	11.25	14%	130.7°
2026-01-15 Thu	100	88	88	18:55–23:00 (good, 4.08 h)	89.7° 17:25	11.23	8%	121.3°
2026-01-16 Fri	100	0	0	—	89.7° 17:20	11.2	4%	111.2°
2026-01-17 Sat	100	89	89	19:00–23:20 (good, 4.33 h)	89.5° 17:15	11.18	1%	100.7°
2026-01-18 Sun	100	0	0	—	89.5° 17:15	11.16	0%	89.9°
2026-01-19 Mon	100	92	92	19:00–23:20 (good, 4.33 h)	89.7° 17:10	11.13	1%	78.9°
2026-01-20 Tue	100	83	83	19:00–22:25 (good, 3.42 h)	89.7° 17:05	11.11	5%	67.9°
2026-01-21 Wed	97	0	0	—	89.6° 17:00	11.08	10%	57.1°
2026-01-22 Thu	92	0	0	—	89.5° 16:55	11.06	17%	46.8°
2026-01-23 Fri	79	54	43	19:05–21:00 (good, 1.92 h)	89.6° 16:55	11.03	26%	37.7°
2026-01-24 Sat	61	9	5	—	89.7° 16:50	11.0	36%	31.2°
2026-01-25 Sun	45	0	0	—	89.7° 16:45	10.97	47%	29.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-12-27&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.