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: 06-25 (52), 06-24 (50), 06-23 (48), 06-22 (47), 06-21 (46) — by astronomy; check the weather when the night is within four days.

2042-05-27astronomy score per night — click a bar for that night2042-06-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-05-27 Tue	13	—	unknown	03:40–03:50 (good, 0.17 h)	89.5° 09:40	4.99	61%	128.7°
2042-05-28 Wed	15	—	unknown	03:35–03:50 (good, 0.25 h)	89.6° 09:40	4.95	70%	136.6°
2042-05-29 Thu	16	—	unknown	03:30–03:50 (good, 0.33 h)	89.8° 09:35	4.91	78%	142.8°
2042-05-30 Fri	14	—	unknown	03:35–03:45 (good, 0.17 h)	89.8° 09:30	4.87	86%	146.4°
2042-05-31 Sat	15	—	unknown	03:30–03:45 (good, 0.25 h)	89.6° 09:25	4.83	92%	146.5°
2042-06-01 Sun	16	—	unknown	03:30–03:45 (good, 0.25 h)	89.5° 09:25	4.79	96%	142.8°
2042-06-02 Mon	17	—	unknown	03:25–03:45 (good, 0.33 h)	89.7° 09:20	4.76	99%	136.3°
2042-06-03 Tue	18	—	unknown	03:20–03:45 (good, 0.42 h)	89.8° 09:15	4.72	100%	127.7°
2042-06-04 Wed	18	—	unknown	03:20–03:45 (good, 0.42 h)	89.7° 09:10	4.69	99%	118.0°
2042-06-05 Thu	17	—	unknown	03:20–03:40 (good, 0.33 h)	89.6° 09:05	4.66	95%	107.4°
2042-06-06 Fri	16	—	unknown	03:25–03:40 (good, 0.25 h)	89.6° 09:05	4.63	90%	96.4°
2042-06-07 Sat	16	—	unknown	03:25–03:40 (good, 0.25 h)	89.7° 09:00	4.6	82%	85.1°
2042-06-08 Sun	16	—	unknown	03:20–03:40 (good, 0.33 h)	89.8° 08:55	4.58	73%	73.7°
2042-06-09 Mon	17	—	unknown	03:15–03:40 (good, 0.42 h)	89.7° 08:50	4.55	62%	62.5°
2042-06-10 Tue	19	—	unknown	03:05–03:40 (good, 0.58 h)	89.5° 08:45	4.53	51%	51.9°
2042-06-11 Wed	22	—	unknown	02:55–03:40 (good, 0.75 h)	89.6° 08:45	4.51	40%	42.5°
2042-06-12 Thu	26	—	unknown	02:35–03:40 (good, 1.08 h)	89.8° 08:40	4.49	29%	35.6°
2042-06-13 Fri	31	—	unknown	02:30–03:40 (good, 1.17 h)	89.8° 08:35	4.48	19%	33.0°
2042-06-14 Sat	35	—	unknown	02:30–03:40 (good, 1.17 h)	89.7° 08:30	4.46	11%	35.7°
2042-06-15 Sun	37	—	unknown	02:25–03:40 (good, 1.25 h)	89.5° 08:30	4.45	5%	42.8°
2042-06-16 Mon	38	—	unknown	02:20–03:40 (good, 1.33 h)	89.7° 08:25	4.44	1%	52.3°
2042-06-17 Tue	39	—	unknown	02:15–03:40 (good, 1.42 h)	89.8° 08:20	4.43	0%	62.9°
2042-06-18 Wed	41	—	unknown	02:10–03:40 (good, 1.5 h)	89.8° 08:15	4.43	2%	74.0°
2042-06-19 Thu	42	—	unknown	02:10–03:40 (good, 1.5 h)	89.6° 08:10	4.42	6%	85.2°
2042-06-20 Fri	44	—	unknown	02:05–03:40 (good, 1.58 h)	89.6° 08:10	4.42	11%	96.1°
2042-06-21 Sat	46	—	unknown	02:00–03:40 (good, 1.67 h)	89.7° 08:05	4.42	18%	106.6°
2042-06-22 Sun	47	—	unknown	01:55–03:40 (good, 1.75 h)	89.8° 08:00	4.42	26%	116.6°
2042-06-23 Mon	48	—	unknown	01:50–03:40 (good, 1.83 h)	89.7° 07:55	4.43	36%	126.0°
2042-06-24 Tue	50	—	unknown	01:50–03:40 (good, 1.83 h)	89.5° 07:50	4.44	45%	134.4°
2042-06-25 Wed	52	—	unknown	01:45–03:40 (good, 1.92 h)	89.6° 07:50	4.44	54%	141.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-05-27&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.