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: 09-23 (100), 09-24 (100), 09-25 (100), 09-26 (100), 09-27 (100) — by astronomy; check the weather when the night is within four days.

2035-09-17astronomy score per night — click a bar for that night2035-10-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-09-17 Mon	50	—	unknown	21:05–05:30 (marginal, 8.42 h)	89.7° 02:20	8.47	100%	44.8°
2035-09-18 Tue	46	—	unknown	21:00–05:35 (marginal, 8.58 h)	89.8° 02:15	8.52	98%	39.4°
2035-09-19 Wed	52	—	unknown	21:00–05:35 (marginal, 8.58 h)	89.7° 02:10	8.57	94%	37.4°
2035-09-20 Thu	85	—	unknown	21:00–21:20 (good, 0.33 h)	89.6° 02:05	8.62	87%	39.6°
2035-09-21 Fri	90	—	unknown	20:55–00:35 (good, 3.67 h)	89.6° 02:05	8.67	79%	45.5°
2035-09-22 Sat	95	—	unknown	20:55–04:15 (good, 7.33 h)	89.7° 02:00	8.73	69%	53.8°
2035-09-23 Sun	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.8° 01:55	8.78	58%	63.7°
2035-09-24 Mon	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.7° 01:50	8.83	46%	74.4°
2035-09-25 Tue	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.5° 01:45	8.88	35%	85.6°
2035-09-26 Wed	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.6° 01:45	8.93	25%	96.8°
2035-09-27 Thu	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.8° 01:40	8.98	16%	107.8°
2035-09-28 Fri	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.7° 01:35	9.02	8%	118.4°
2035-09-29 Sat	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.6° 01:30	9.07	3%	127.9°
2035-09-30 Sun	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.5° 01:30	9.12	0%	135.7°
2035-10-01 Mon	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.7° 01:25	9.17	0%	140.9°
2035-10-02 Tue	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.8° 01:20	9.22	2%	142.6°
2035-10-03 Wed	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:15	9.27	6%	140.5°
2035-10-04 Thu	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.6° 01:10	9.31	12%	135.4°
2035-10-05 Fri	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.6° 01:10	9.36	19%	128.3°
2035-10-06 Sat	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.7° 01:05	9.41	27%	120.2°
2035-10-07 Sun	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.8° 01:00	9.45	36%	111.4°
2035-10-08 Mon	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.7° 00:55	9.5	45%	102.3°
2035-10-09 Tue	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.5° 00:50	9.55	55%	92.9°
2035-10-10 Wed	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.6° 00:50	9.59	64%	83.5°
2035-10-11 Thu	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.8° 00:45	9.64	73%	74.0°
2035-10-12 Fri	100	—	unknown	21:00–06:00 (good, 9.0 h)	89.7° 00:40	9.68	81%	64.6°
2035-10-13 Sat	93	—	unknown	01:25–06:00 (good, 4.58 h)	89.6° 00:35	9.73	89%	55.6°
2035-10-14 Sun	85	—	unknown	05:20–06:05 (good, 0.75 h)	89.5° 00:35	9.77	94%	47.4°
2035-10-15 Mon	50	—	unknown	20:15–06:05 (marginal, 9.83 h)	89.7° 00:30	9.81	98%	41.0°
2035-10-16 Tue	46	—	unknown	20:15–06:05 (marginal, 9.83 h)	89.8° 00:25	9.86	100%	37.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-09-17&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.