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: 02-19 (40), 02-20 (40), 02-21 (39), 02-18 (36), 02-22 (36) — by astronomy; check the weather when the night is within four days.

2030-02-16astronomy score per night — click a bar for that night2030-03-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-02-16 Sat	30	—	unknown	19:30–21:00 (good, 1.5 h)	89.7° 15:20	10.2	98%	103.6°
2030-02-17 Sun	34	—	unknown	19:30–21:05 (good, 1.58 h)	89.7° 15:15	10.16	100%	115.2°
2030-02-18 Mon	36	—	unknown	19:35–21:10 (good, 1.58 h)	89.6° 15:10	10.12	99%	126.5°
2030-02-19 Tue	40	—	unknown	19:35–21:05 (good, 1.5 h)	89.5° 15:05	10.08	96%	137.1°
2030-02-20 Wed	40	—	unknown	19:35–21:05 (good, 1.5 h)	89.6° 15:05	10.04	91%	145.8°
2030-02-21 Thu	39	—	unknown	19:35–21:10 (good, 1.58 h)	89.7° 15:00	10.0	83%	150.5°
2030-02-22 Fri	36	—	unknown	19:40–21:05 (good, 1.42 h)	89.7° 14:55	9.95	74%	149.3°
2030-02-23 Sat	35	—	unknown	19:40–21:00 (good, 1.33 h)	89.6° 14:50	9.91	63%	142.8°
2030-02-24 Sun	33	—	unknown	19:40–20:55 (good, 1.25 h)	89.5° 14:50	9.87	52%	133.3°
2030-02-25 Mon	31	—	unknown	19:40–20:50 (good, 1.17 h)	89.6° 14:45	9.82	40%	122.2°
2030-02-26 Tue	29	—	unknown	19:45–20:50 (good, 1.08 h)	89.7° 14:40	9.78	30%	110.6°
2030-02-27 Wed	28	—	unknown	19:45–20:45 (good, 1.0 h)	89.7° 14:35	9.74	20%	98.7°
2030-02-28 Thu	26	—	unknown	19:45–20:40 (good, 0.92 h)	89.6° 14:30	9.69	12%	86.8°
2030-03-01 Fri	25	—	unknown	19:45–20:35 (good, 0.83 h)	89.5° 14:30	9.65	6%	75.2°
2030-03-02 Sat	23	—	unknown	19:45–20:35 (good, 0.83 h)	89.7° 14:25	9.6	2%	63.9°
2030-03-03 Sun	21	—	unknown	19:50–20:30 (good, 0.67 h)	89.7° 14:20	9.55	0%	53.2°
2030-03-04 Mon	20	—	unknown	19:50–20:25 (good, 0.58 h)	89.7° 14:15	9.51	1%	43.6°
2030-03-05 Tue	18	—	unknown	19:50–20:20 (good, 0.5 h)	89.5° 14:10	9.46	3%	35.7°
2030-03-06 Wed	15	—	unknown	19:50–20:15 (good, 0.42 h)	89.6° 14:10	9.41	7%	30.5°
2030-03-07 Thu	11	—	unknown	19:55–20:05 (good, 0.17 h)	89.7° 14:05	9.37	13%	29.4°
2030-03-08 Fri	9	—	unknown	19:20–20:40 (marginal, 1.33 h)	89.7° 14:00	9.32	20%	32.6°
2030-03-09 Sat	7	—	unknown	19:55–20:40 (marginal, 0.75 h)	89.6° 13:55	9.27	28%	39.0°
2030-03-10 Sun	6	—	unknown	19:55–20:35 (marginal, 0.67 h)	89.5° 13:55	9.22	37%	47.2°
2030-03-11 Mon	4	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.6° 13:50	9.17	46%	56.4°
2030-03-12 Tue	3	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.7° 13:45	9.12	56%	66.4°
2030-03-13 Wed	3	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.7° 13:40	9.07	65%	76.8°
2030-03-14 Thu	2	—	unknown	20:00–20:15 (marginal, 0.25 h)	89.6° 13:35	9.02	74%	87.7°
2030-03-15 Fri	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.5° 13:35	8.97	83%	99.0°
2030-03-16 Sat	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.7° 13:30	8.92	90%	110.4°
2030-03-17 Sun	1	—	unknown	—	89.7° 13:25	8.87	96%	121.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-02-16&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.