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: 09-03 (100), 09-04 (100), 09-05 (100), 09-06 (100), 09-07 (100) — by astronomy; check the weather when the night is within four days.

2037-08-27astronomy score per night — click a bar for that night2037-09-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-08-27 Thu	47	—	unknown	21:45–05:05 (marginal, 7.33 h)	89.8° 03:40	7.35	96%	47.1°
2037-08-28 Fri	50	—	unknown	21:45–05:05 (marginal, 7.33 h)	89.8° 03:35	7.41	91%	41.8°
2037-08-29 Sat	80	—	unknown	21:40–22:05 (good, 0.42 h)	89.6° 03:30	7.46	85%	38.9°
2037-08-30 Sun	84	—	unknown	21:40–23:15 (good, 1.58 h)	89.5° 03:30	7.52	78%	38.9°
2037-08-31 Mon	87	—	unknown	21:35–02:30 (good, 4.92 h)	89.7° 03:25	7.57	69%	42.0°
2037-09-01 Tue	91	—	unknown	21:35–05:10 (good, 7.58 h)	89.8° 03:20	7.63	60%	47.6°
2037-09-02 Wed	96	—	unknown	21:35–05:15 (good, 7.67 h)	89.7° 03:15	7.69	50%	55.1°
2037-09-03 Thu	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.6° 03:10	7.74	40%	64.0°
2037-09-04 Fri	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.6° 03:10	7.8	29%	73.9°
2037-09-05 Sat	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.7° 03:05	7.85	20%	84.5°
2037-09-06 Sun	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.8° 03:00	7.91	12%	95.6°
2037-09-07 Mon	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.7° 02:55	7.96	5%	107.0°
2037-09-08 Tue	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.5° 02:50	8.02	1%	118.1°
2037-09-09 Wed	100	—	unknown	21:20–05:25 (good, 8.08 h)	89.6° 02:50	8.07	0%	128.2°
2037-09-10 Thu	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.8° 02:45	8.12	2%	136.3°
2037-09-11 Fri	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.8° 02:40	8.18	7%	140.9°
2037-09-12 Sat	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.6° 02:35	8.23	15%	141.0°
2037-09-13 Sun	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.5° 02:35	8.28	24%	136.7°
2037-09-14 Mon	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.7° 02:30	8.34	34%	129.5°
2037-09-15 Tue	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.8° 02:25	8.39	45%	120.8°
2037-09-16 Wed	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:20	8.44	55%	111.4°
2037-09-17 Thu	100	—	unknown	21:05–05:35 (good, 8.5 h)	89.6° 02:15	8.49	65%	101.7°
2037-09-18 Fri	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.6° 02:15	8.55	74%	92.0°
2037-09-19 Sat	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.7° 02:10	8.6	82%	82.4°
2037-09-20 Sun	100	—	unknown	21:55–05:35 (good, 7.67 h)	89.8° 02:05	8.65	89%	73.1°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-08-27&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.