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: 09-29 (100), 09-30 (100), 10-01 (100), 10-02 (100), 10-03 (100) — by astronomy; check the weather when the night is within four days.

2029-09-21astronomy score per night — click a bar for that night2029-10-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-09-21 Fri	54	—	unknown	20:55–05:40 (marginal, 8.75 h)	89.7° 02:00	8.7	99%	44.7°
2029-09-22 Sat	39	—	unknown	20:55–05:40 (marginal, 8.75 h)	89.5° 01:55	8.75	100%	36.7°
2029-09-23 Sun	33	—	unknown	20:50–00:30 (marginal, 3.67 h)	89.6° 01:55	8.8	98%	31.0°
2029-09-24 Mon	37	—	unknown	20:50–01:15 (marginal, 4.42 h)	89.7° 01:50	8.85	95%	28.9°
2029-09-25 Tue	47	—	unknown	20:50–05:40 (marginal, 8.83 h)	89.7° 01:45	8.9	91%	31.1°
2029-09-26 Wed	84	—	unknown	20:45–20:50 (good, 0.08 h)	89.6° 01:40	8.95	84%	36.8°
2029-09-27 Thu	89	—	unknown	20:45–00:15 (good, 3.5 h)	89.5° 01:35	9.0	77%	44.7°
2029-09-28 Fri	94	—	unknown	20:45–03:45 (good, 7.0 h)	89.6° 01:35	9.05	69%	53.9°
2029-09-29 Sat	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.7° 01:30	9.1	59%	63.9°
2029-09-30 Sun	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.7° 01:25	9.14	50%	74.5°
2029-10-01 Mon	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.6° 01:20	9.19	39%	85.6°
2029-10-02 Tue	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.5° 01:20	9.24	29%	97.0°
2029-10-03 Wed	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:15	9.29	20%	108.8°
2029-10-04 Thu	100	—	unknown	20:30–05:50 (good, 9.33 h)	89.7° 01:10	9.34	12%	120.7°
2029-10-05 Fri	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.7° 01:05	9.38	5%	132.2°
2029-10-06 Sat	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.5° 01:00	9.43	1%	142.5°
2029-10-07 Sun	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.6° 01:00	9.48	0%	149.6°
2029-10-08 Mon	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.7° 00:55	9.52	2%	150.6°
2029-10-09 Tue	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.7° 00:50	9.57	7%	145.1°
2029-10-10 Wed	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.6° 00:45	9.61	14%	135.5°
2029-10-11 Thu	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.5° 00:40	9.66	23%	124.2°
2029-10-12 Fri	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.6° 00:40	9.7	33%	112.4°
2029-10-13 Sat	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.7° 00:35	9.75	44%	100.6°
2029-10-14 Sun	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.7° 00:30	9.79	55%	89.0°
2029-10-15 Mon	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:25	9.83	65%	77.7°
2029-10-16 Tue	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.5° 00:25	9.88	74%	66.8°
2029-10-17 Wed	95	—	unknown	23:45–06:05 (good, 6.33 h)	89.7° 00:20	9.92	82%	56.5°
2029-10-18 Thu	88	—	unknown	02:55–06:10 (good, 3.25 h)	89.7° 00:15	9.96	89%	46.9°
2029-10-19 Fri	81	—	unknown	05:40–06:10 (good, 0.5 h)	89.7° 00:10	10.0	94%	38.5°
2029-10-20 Sat	41	—	unknown	00:45–06:10 (marginal, 5.42 h)	89.5° 00:05	10.05	98%	32.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-09-21&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.