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: 06-22 (46), 06-23 (46), 06-21 (45), 06-20 (44), 06-19 (43) — by astronomy; check the weather when the night is within four days.

2037-05-25astronomy score per night — click a bar for that night2037-06-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-05-25 Mon	10	—	unknown	03:10–03:50 (marginal, 0.67 h)	89.7° 09:50	5.07	87%	141.3°
2037-05-26 Tue	10	—	unknown	03:10–04:40 (marginal, 1.5 h)	89.8° 09:45	5.02	93%	140.7°
2037-05-27 Wed	11	—	unknown	03:05–04:40 (marginal, 1.58 h)	89.7° 09:40	4.98	98%	136.2°
2037-05-28 Thu	12	—	unknown	03:45–03:50 (good, 0.08 h)	89.5° 09:35	4.94	100%	128.8°
2037-05-29 Fri	13	—	unknown	03:40–03:50 (good, 0.17 h)	89.6° 09:35	4.9	99%	119.9°
2037-05-30 Sat	12	—	unknown	02:50–04:35 (marginal, 1.75 h)	89.8° 09:30	4.86	96%	110.2°
2037-05-31 Sun	11	—	unknown	02:50–04:35 (marginal, 1.75 h)	89.8° 09:25	4.82	92%	100.3°
2037-06-01 Mon	12	—	unknown	02:45–04:35 (marginal, 1.83 h)	89.6° 09:20	4.78	85%	90.5°
2037-06-02 Tue	12	—	unknown	02:40–04:35 (marginal, 1.92 h)	89.5° 09:20	4.75	77%	80.8°
2037-06-03 Wed	13	—	unknown	03:40–03:45 (good, 0.08 h)	89.7° 09:15	4.72	69%	71.5°
2037-06-04 Thu	14	—	unknown	03:35–03:40 (good, 0.08 h)	89.8° 09:10	4.68	60%	62.7°
2037-06-05 Fri	16	—	unknown	03:25–03:40 (good, 0.25 h)	89.7° 09:05	4.65	50%	54.6°
2037-06-06 Sat	18	—	unknown	03:15–03:40 (good, 0.42 h)	89.6° 09:00	4.62	41%	47.5°
2037-06-07 Sun	21	—	unknown	02:55–03:40 (good, 0.75 h)	89.6° 09:00	4.6	32%	42.1°
2037-06-08 Mon	27	—	unknown	02:50–03:40 (good, 0.83 h)	89.7° 08:55	4.57	23%	38.9°
2037-06-09 Tue	28	—	unknown	02:45–03:40 (good, 0.92 h)	89.8° 08:50	4.55	15%	38.9°
2037-06-10 Wed	30	—	unknown	02:40–03:40 (good, 1.0 h)	89.7° 08:45	4.53	9%	42.1°
2037-06-11 Thu	31	—	unknown	02:40–03:40 (good, 1.0 h)	89.5° 08:40	4.51	4%	48.1°
2037-06-12 Fri	33	—	unknown	02:35–03:40 (good, 1.08 h)	89.6° 08:40	4.49	1%	56.1°
2037-06-13 Sat	34	—	unknown	02:30–03:40 (good, 1.17 h)	89.8° 08:35	4.47	0%	65.6°
2037-06-14 Sun	35	—	unknown	02:25–03:40 (good, 1.25 h)	89.8° 08:30	4.46	2%	75.9°
2037-06-15 Mon	37	—	unknown	02:25–03:40 (good, 1.25 h)	89.6° 08:25	4.45	6%	86.8°
2037-06-16 Tue	38	—	unknown	02:20–03:40 (good, 1.33 h)	89.5° 08:25	4.44	13%	97.9°
2037-06-17 Wed	40	—	unknown	02:15–03:40 (good, 1.42 h)	89.7° 08:20	4.43	21%	108.8°
2037-06-18 Thu	41	—	unknown	02:10–03:40 (good, 1.5 h)	89.8° 08:15	4.43	32%	119.2°
2037-06-19 Fri	43	—	unknown	02:05–03:40 (good, 1.58 h)	89.7° 08:10	4.42	43%	128.5°
2037-06-20 Sat	44	—	unknown	02:05–03:40 (good, 1.58 h)	89.6° 08:05	4.42	54%	136.0°
2037-06-21 Sun	45	—	unknown	02:05–03:40 (good, 1.58 h)	89.6° 08:05	4.42	65%	140.6°
2037-06-22 Mon	46	—	unknown	02:00–03:40 (good, 1.67 h)	89.7° 08:00	4.43	76%	141.2°
2037-06-23 Tue	46	—	unknown	02:00–03:40 (good, 1.67 h)	89.8° 07:55	4.43	85%	137.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-05-25&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.