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 V1057 Cyg: 03-21 (43), 03-18 (42), 03-19 (42), 03-20 (42), 03-22 (42) — by astronomy; check the weather when the night is within four days.

2040-02-28astronomy score per night — click a bar for that night2040-03-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-02-28 Tue	20	—	unknown	04:50–05:25 (good, 0.58 h)	87.3° 10:45	9.71	99%	117.0°
2040-02-29 Wed	20	—	unknown	04:45–05:25 (good, 0.67 h)	87.2° 10:40	9.66	96%	115.1°
2040-03-01 Thu	20	—	unknown	04:45–05:25 (good, 0.67 h)	87.3° 10:40	9.62	91%	111.7°
2040-03-02 Fri	20	—	unknown	04:40–05:20 (good, 0.67 h)	87.3° 10:35	9.57	84%	107.2°
2040-03-03 Sat	21	—	unknown	04:35–05:20 (good, 0.75 h)	87.3° 10:30	9.53	75%	101.8°
2040-03-04 Sun	22	—	unknown	04:30–05:20 (good, 0.83 h)	87.3° 10:25	9.48	65%	95.7°
2040-03-05 Mon	22	—	unknown	04:25–05:15 (good, 0.83 h)	87.2° 10:25	9.43	54%	89.3°
2040-03-06 Tue	25	—	unknown	04:15–05:15 (good, 1.0 h)	87.3° 10:20	9.39	43%	82.9°
2040-03-07 Wed	28	—	unknown	04:10–05:15 (good, 1.08 h)	87.3° 10:15	9.34	32%	76.7°
2040-03-08 Thu	32	—	unknown	03:55–05:10 (good, 1.25 h)	87.3° 10:10	9.29	22%	71.2°
2040-03-09 Fri	34	—	unknown	03:50–05:10 (good, 1.33 h)	87.3° 10:05	9.24	13%	66.8°
2040-03-10 Sat	35	—	unknown	03:50–05:10 (good, 1.33 h)	87.3° 10:05	9.19	6%	63.7°
2040-03-11 Sun	35	—	unknown	03:45–05:05 (good, 1.33 h)	87.3° 10:00	9.15	2%	62.5°
2040-03-12 Mon	37	—	unknown	03:40–05:05 (good, 1.42 h)	87.3° 09:55	9.1	0%	63.0°
2040-03-13 Tue	38	—	unknown	03:35–05:05 (good, 1.5 h)	87.3° 09:50	9.05	1%	65.2°
2040-03-14 Wed	38	—	unknown	03:30–05:00 (good, 1.5 h)	87.2° 09:45	9.0	4%	68.8°
2040-03-15 Thu	39	—	unknown	03:30–05:00 (good, 1.5 h)	87.3° 09:45	8.95	10%	73.4°
2040-03-16 Fri	40	—	unknown	03:25–05:00 (good, 1.58 h)	87.3° 09:40	8.9	16%	78.5°
2040-03-17 Sat	40	—	unknown	03:20–04:55 (good, 1.58 h)	87.3° 09:35	8.84	24%	84.0°
2040-03-18 Sun	42	—	unknown	03:15–04:55 (good, 1.67 h)	87.3° 09:30	8.79	33%	89.6°
2040-03-19 Mon	42	—	unknown	03:15–04:55 (good, 1.67 h)	87.2° 09:30	8.74	42%	95.1°
2040-03-20 Tue	42	—	unknown	03:10–04:50 (good, 1.67 h)	87.3° 09:25	8.69	52%	100.4°
2040-03-21 Wed	43	—	unknown	03:10–04:50 (good, 1.67 h)	87.3° 09:20	8.64	61%	105.3°
2040-03-22 Thu	42	—	unknown	03:10–04:45 (good, 1.58 h)	87.3° 09:15	8.59	70%	109.7°
2040-03-23 Fri	42	—	unknown	03:10–04:45 (good, 1.58 h)	87.3° 09:10	8.53	78%	113.3°
2040-03-24 Sat	38	—	unknown	04:05–05:45 (good, 1.67 h)	87.3° 10:10	8.48	86%	115.9°
2040-03-25 Sun	37	—	unknown	04:05–05:40 (good, 1.58 h)	87.3° 10:05	8.43	92%	117.3°
2040-03-26 Mon	38	—	unknown	04:00–05:40 (good, 1.67 h)	87.3° 10:00	8.37	97%	117.4°
2040-03-27 Tue	37	—	unknown	04:00–05:40 (good, 1.67 h)	87.3° 09:55	8.32	99%	115.9°
2040-03-28 Wed	36	—	unknown	04:00–05:35 (good, 1.58 h)	87.2° 09:50	8.27	100%	113.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-02-28&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.