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: 02-18 (45), 02-19 (43), 02-20 (41), 02-21 (40), 02-22 (37) — by astronomy; check the weather when the night is within four days.

2047-02-18astronomy score per night — click a bar for that night2047-03-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-02-18 Mon	45	—	unknown	19:35–21:20 (good, 1.75 h)	89.5° 15:15	10.13	32%	121.7°
2047-02-19 Tue	43	—	unknown	19:35–21:20 (good, 1.75 h)	89.7° 15:10	10.09	22%	110.3°
2047-02-20 Wed	41	—	unknown	19:35–21:15 (good, 1.67 h)	89.8° 15:05	10.04	14%	98.8°
2047-02-21 Thu	40	—	unknown	19:35–21:10 (good, 1.58 h)	89.8° 15:00	10.0	8%	87.4°
2047-02-22 Fri	37	—	unknown	19:40–21:05 (good, 1.42 h)	89.6° 14:55	9.96	3%	76.2°
2047-02-23 Sat	35	—	unknown	19:40–21:00 (good, 1.33 h)	89.6° 14:55	9.92	1%	65.4°
2047-02-24 Sun	33	—	unknown	19:40–21:00 (good, 1.33 h)	89.8° 14:50	9.87	0%	55.0°
2047-02-25 Mon	32	—	unknown	19:40–20:55 (good, 1.25 h)	89.8° 14:45	9.83	1%	45.4°
2047-02-26 Tue	30	—	unknown	19:40–20:50 (good, 1.17 h)	89.7° 14:40	9.79	4%	37.1°
2047-02-27 Wed	26	—	unknown	19:45–20:40 (good, 0.92 h)	89.5° 14:35	9.74	9%	30.9°
2047-02-28 Thu	22	—	unknown	19:45–20:35 (good, 0.83 h)	89.6° 14:35	9.7	15%	28.3°
2047-03-01 Fri	18	—	unknown	19:45–20:25 (good, 0.67 h)	89.8° 14:30	9.65	23%	29.9°
2047-03-02 Sat	15	—	unknown	19:45–20:10 (good, 0.42 h)	89.8° 14:25	9.61	31%	35.4°
2047-03-03 Sun	12	—	unknown	19:15–21:05 (marginal, 1.83 h)	89.7° 14:20	9.56	40%	43.2°
2047-03-04 Mon	10	—	unknown	19:50–20:55 (marginal, 1.08 h)	89.5° 14:20	9.51	50%	52.5°
2047-03-05 Tue	8	—	unknown	19:50–20:50 (marginal, 1.0 h)	89.7° 14:15	9.47	60%	62.8°
2047-03-06 Wed	7	—	unknown	19:50–20:45 (marginal, 0.92 h)	89.8° 14:10	9.42	70%	73.8°
2047-03-07 Thu	7	—	unknown	19:55–20:40 (marginal, 0.75 h)	89.8° 14:05	9.37	79%	85.3°
2047-03-08 Fri	7	—	unknown	19:55–20:45 (marginal, 0.83 h)	89.6° 14:00	9.32	87%	97.4°
2047-03-09 Sat	7	—	unknown	19:55–20:40 (marginal, 0.75 h)	89.6° 14:00	9.28	94%	109.7°
2047-03-10 Sun	7	—	unknown	19:55–20:35 (marginal, 0.67 h)	89.8° 13:55	9.23	98%	122.1°
2047-03-11 Mon	6	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.8° 13:50	9.18	100%	133.9°
2047-03-12 Tue	6	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.7° 13:45	9.13	99%	144.2°
2047-03-13 Wed	6	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.6° 13:40	9.08	95%	150.7°
2047-03-14 Thu	5	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.6° 13:40	9.03	88%	150.9°
2047-03-15 Fri	3	—	unknown	19:30–19:45 (marginal, 0.25 h)	89.8° 13:35	8.98	79%	144.8°
2047-03-16 Sat	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.8° 13:30	8.93	69%	135.3°
2047-03-17 Sun	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.7° 13:25	8.88	58%	124.3°
2047-03-18 Mon	1	—	unknown	—	89.5° 13:25	8.83	47%	112.9°
2047-03-19 Tue	1	—	unknown	—	89.7° 13:20	8.78	37%	101.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-02-18&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.