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: 08-07 (100), 08-08 (100), 08-09 (100), 08-10 (100), 08-11 (100) — by astronomy; check the weather when the night is within four days.

2037-07-28astronomy score per night — click a bar for that night2037-08-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-07-28 Tue	49	—	unknown	02:50–04:20 (good, 1.5 h)	89.5° 05:35	5.65	97%	68.3°
2037-07-29 Wed	44	—	unknown	23:00–04:20 (marginal, 5.33 h)	89.6° 05:35	5.7	93%	59.7°
2037-07-30 Thu	42	—	unknown	22:55–04:25 (marginal, 5.5 h)	89.8° 05:30	5.76	87%	52.0°
2037-07-31 Fri	46	—	unknown	22:50–04:25 (marginal, 5.58 h)	89.7° 05:25	5.81	80%	45.4°
2037-08-01 Sat	64	—	unknown	23:20–23:40 (good, 0.33 h)	89.6° 05:20	5.87	72%	40.8°
2037-08-02 Sun	81	—	unknown	23:15–04:30 (good, 5.25 h)	89.5° 05:20	5.92	63%	38.7°
2037-08-03 Mon	85	—	unknown	23:10–04:30 (good, 5.33 h)	89.7° 05:15	5.98	54%	39.6°
2037-08-04 Tue	89	—	unknown	23:05–04:30 (good, 5.42 h)	89.8° 05:10	6.03	44%	43.6°
2037-08-05 Wed	93	—	unknown	23:00–04:30 (good, 5.5 h)	89.7° 05:05	6.09	34%	50.0°
2037-08-06 Thu	99	—	unknown	23:00–04:35 (good, 5.58 h)	89.6° 05:00	6.15	25%	58.2°
2037-08-07 Fri	100	—	unknown	22:55–04:35 (good, 5.67 h)	89.6° 05:00	6.2	16%	67.7°
2037-08-08 Sat	100	—	unknown	22:50–04:35 (good, 5.75 h)	89.7° 04:55	6.26	9%	78.2°
2037-08-09 Sun	100	—	unknown	22:45–04:40 (good, 5.92 h)	89.8° 04:50	6.32	3%	89.3°
2037-08-10 Mon	100	—	unknown	22:45–04:40 (good, 5.92 h)	89.7° 04:45	6.37	0%	100.8°
2037-08-11 Tue	100	—	unknown	22:40–04:40 (good, 6.0 h)	89.5° 04:40	6.43	0%	112.1°
2037-08-12 Wed	100	—	unknown	22:35–04:45 (good, 6.17 h)	89.6° 04:40	6.49	3%	122.7°
2037-08-13 Thu	100	—	unknown	22:30–04:45 (good, 6.25 h)	89.8° 04:35	6.55	9%	131.9°
2037-08-14 Fri	100	—	unknown	22:30–04:45 (good, 6.25 h)	89.8° 04:30	6.6	17%	138.6°
2037-08-15 Sat	100	—	unknown	22:25–04:50 (good, 6.42 h)	89.6° 04:25	6.66	27%	141.4°
2037-08-16 Sun	100	—	unknown	22:25–04:50 (good, 6.42 h)	89.5° 04:25	6.72	38%	139.8°
2037-08-17 Mon	100	—	unknown	22:20–04:50 (good, 6.5 h)	89.7° 04:20	6.78	49%	134.6°
2037-08-18 Tue	100	—	unknown	22:20–04:55 (good, 6.58 h)	89.8° 04:15	6.83	60%	127.1°
2037-08-19 Wed	100	—	unknown	22:15–04:55 (good, 6.67 h)	89.7° 04:10	6.89	70%	118.3°
2037-08-20 Thu	100	—	unknown	22:20–04:55 (good, 6.58 h)	89.6° 04:05	6.95	79%	108.9°
2037-08-21 Fri	100	—	unknown	22:20–04:55 (good, 6.58 h)	89.6° 04:05	7.01	86%	99.2°
2037-08-22 Sat	100	—	unknown	22:25–05:00 (good, 6.58 h)	89.7° 04:00	7.06	92%	89.6°
2037-08-23 Sun	78	—	unknown	23:35–05:00 (good, 5.42 h)	89.8° 03:55	7.12	97%	80.0°
2037-08-24 Mon	70	—	unknown	00:50–05:00 (good, 4.17 h)	89.7° 03:50	7.18	99%	70.8°
2037-08-25 Tue	62	—	unknown	04:25–05:05 (good, 0.67 h)	89.5° 03:45	7.24	100%	62.0°
2037-08-26 Wed	54	—	unknown	21:45–05:05 (marginal, 7.33 h)	89.6° 03:45	7.29	99%	54.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-07-28&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.