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: 10-01 (100), 10-02 (100), 10-03 (100), 10-04 (100), 10-05 (100) — by astronomy; check the weather when the night is within four days.

2037-09-21astronomy score per night — click a bar for that night2037-10-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-09-21 Mon	99	—	unknown	00:40–05:40 (good, 5.0 h)	89.7° 02:00	8.7	94%	64.3°
2037-09-22 Tue	64	—	unknown	03:50–05:40 (good, 1.83 h)	89.5° 01:55	8.75	98%	56.0°
2037-09-23 Wed	55	—	unknown	20:50–05:40 (marginal, 8.83 h)	89.6° 01:55	8.8	100%	48.7°
2037-09-24 Thu	48	—	unknown	20:50–05:40 (marginal, 8.83 h)	89.8° 01:50	8.85	100%	42.9°
2037-09-25 Fri	50	—	unknown	20:50–05:40 (marginal, 8.83 h)	89.8° 01:45	8.9	98%	39.3°
2037-09-26 Sat	54	—	unknown	20:45–05:45 (marginal, 9.0 h)	89.6° 01:40	8.95	94%	38.5°
2037-09-27 Sun	86	—	unknown	20:45–21:05 (good, 0.33 h)	89.5° 01:40	9.0	89%	40.8°
2037-09-28 Mon	90	—	unknown	20:45–23:45 (good, 3.0 h)	89.7° 01:35	9.05	83%	45.7°
2037-09-29 Tue	94	—	unknown	20:40–02:05 (good, 5.42 h)	89.8° 01:30	9.1	75%	52.7°
2037-09-30 Wed	99	—	unknown	20:40–05:00 (good, 8.33 h)	89.7° 01:25	9.15	66%	61.1°
2037-10-01 Thu	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.6° 01:20	9.2	55%	70.5°
2037-10-02 Fri	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.6° 01:20	9.24	45%	80.6°
2037-10-03 Sat	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:15	9.29	34%	91.3°
2037-10-04 Sun	100	—	unknown	20:30–05:50 (good, 9.33 h)	89.8° 01:10	9.34	24%	102.2°
2037-10-05 Mon	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.7° 01:05	9.38	15%	113.2°
2037-10-06 Tue	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.5° 01:00	9.43	7%	123.7°
2037-10-07 Wed	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.6° 01:00	9.48	2%	132.8°
2037-10-08 Thu	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.8° 00:55	9.52	0%	139.3°
2037-10-09 Fri	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.8° 00:50	9.57	1%	141.6°
2037-10-10 Sat	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.6° 00:45	9.61	5%	139.1°
2037-10-11 Sun	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.5° 00:45	9.66	11%	132.8°
2037-10-12 Mon	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.7° 00:40	9.7	20%	124.2°
2037-10-13 Tue	100	—	unknown	20:15–06:00 (good, 9.75 h)	89.8° 00:35	9.75	29%	114.7°
2037-10-14 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.7° 00:30	9.79	39%	104.8°
2037-10-15 Thu	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:25	9.84	49%	94.9°
2037-10-16 Fri	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:25	9.88	59%	85.1°
2037-10-17 Sat	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.7° 00:20	9.92	68%	75.7°
2037-10-18 Sun	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.8° 00:15	9.96	77%	66.7°
2037-10-19 Mon	94	—	unknown	22:40–06:10 (good, 7.5 h)	89.7° 00:10	10.01	84%	58.2°
2037-10-20 Tue	87	—	unknown	02:35–06:10 (good, 3.58 h)	89.5° 00:05	10.05	90%	50.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-09-21&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.