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: 09-12 (100), 09-13 (100), 09-14 (100), 09-15 (100), 09-16 (100) — by astronomy; check the weather when the night is within four days.

2039-09-12astronomy score per night — click a bar for that night2039-10-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-09-12 Mon	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.7° 02:40	8.2	28%	78.6°
2039-09-13 Tue	100	—	unknown	21:10–05:25 (good, 8.25 h)	89.8° 02:35	8.26	20%	88.2°
2039-09-14 Wed	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.8° 02:30	8.31	13%	98.1°
2039-09-15 Thu	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.6° 02:25	8.36	7%	108.1°
2039-09-16 Fri	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.6° 02:25	8.42	3%	117.9°
2039-09-17 Sat	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:20	8.47	0%	127.2°
2039-09-18 Sun	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.8° 02:15	8.52	1%	135.3°
2039-09-19 Mon	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.7° 02:10	8.57	3%	141.0°
2039-09-20 Tue	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.5° 02:05	8.62	8%	143.0°
2039-09-21 Wed	100	—	unknown	20:55–05:35 (good, 8.67 h)	89.6° 02:05	8.68	16%	140.4°
2039-09-22 Thu	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.8° 02:00	8.73	25%	134.0°
2039-09-23 Fri	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.8° 01:55	8.78	36%	125.3°
2039-09-24 Sat	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.7° 01:50	8.83	47%	115.1°
2039-09-25 Sun	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.5° 01:45	8.88	58%	104.3°
2039-09-26 Mon	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.7° 01:45	8.93	69%	93.2°
2039-09-27 Tue	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.8° 01:40	8.98	79%	82.2°
2039-09-28 Wed	100	—	unknown	21:15–05:45 (good, 8.5 h)	89.8° 01:35	9.03	87%	71.4°
2039-09-29 Thu	96	—	unknown	01:20–05:45 (good, 4.42 h)	89.6° 01:30	9.08	94%	61.2°
2039-09-30 Fri	60	—	unknown	20:40–05:45 (marginal, 9.08 h)	89.5° 01:30	9.12	98%	52.0°
2039-10-01 Sat	50	—	unknown	20:40–05:50 (marginal, 9.17 h)	89.7° 01:25	9.17	100%	44.3°
2039-10-02 Sun	48	—	unknown	20:35–05:50 (marginal, 9.25 h)	89.8° 01:20	9.22	100%	39.1°
2039-10-03 Mon	50	—	unknown	20:35–05:50 (marginal, 9.25 h)	89.7° 01:15	9.27	97%	37.0°
2039-10-04 Tue	55	—	unknown	20:35–05:50 (marginal, 9.25 h)	89.6° 01:10	9.32	93%	38.5°
2039-10-05 Wed	88	—	unknown	20:30–22:25 (good, 1.92 h)	89.6° 01:10	9.36	87%	43.0°
2039-10-06 Thu	92	—	unknown	20:30–00:15 (good, 3.75 h)	89.7° 01:05	9.41	80%	49.6°
2039-10-07 Fri	97	—	unknown	20:30–03:15 (good, 6.75 h)	89.8° 01:00	9.46	72%	57.4°
2039-10-08 Sat	100	—	unknown	20:25–05:05 (good, 8.67 h)	89.7° 00:55	9.5	64%	66.0°
2039-10-09 Sun	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.5° 00:50	9.55	54%	75.1°
2039-10-10 Mon	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.7° 00:50	9.59	45%	84.6°
2039-10-11 Tue	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.8° 00:45	9.64	35%	94.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-09-12&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.