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 North America Nebula: 09-13 (100), 09-14 (100), 09-15 (100), 09-16 (100), 09-17 (100) — by astronomy; check the weather when the night is within four days.

2044-09-13astronomy score per night — click a bar for that night2044-10-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-09-13 Tue	100	—	unknown	21:10–04:40 (good, 7.5 h)	87.2° 22:50	8.3	58%	87.0°
2044-09-14 Wed	100	—	unknown	21:10–04:45 (good, 7.58 h)	87.2° 22:45	8.35	47%	94.6°
2044-09-15 Thu	100	—	unknown	21:05–04:50 (good, 7.75 h)	87.2° 22:40	8.41	36%	102.0°
2044-09-16 Fri	100	—	unknown	21:05–04:50 (good, 7.75 h)	87.2° 22:35	8.46	25%	109.0°
2044-09-17 Sat	100	—	unknown	21:05–04:50 (good, 7.75 h)	87.2° 22:30	8.51	16%	115.0°
2044-09-18 Sun	100	—	unknown	21:00–04:50 (good, 7.83 h)	87.2° 22:30	8.56	8%	119.5°
2044-09-19 Mon	100	—	unknown	21:00–04:45 (good, 7.75 h)	87.2° 22:25	8.61	3%	122.1°
2044-09-20 Tue	100	—	unknown	20:55–04:40 (good, 7.75 h)	87.2° 22:20	8.67	0%	122.6°
2044-09-21 Wed	100	—	unknown	20:55–04:35 (good, 7.67 h)	87.2° 22:15	8.72	0%	120.9°
2044-09-22 Thu	100	—	unknown	20:55–04:35 (good, 7.67 h)	87.2° 22:10	8.77	3%	117.4°
2044-09-23 Fri	100	—	unknown	20:50–04:30 (good, 7.67 h)	87.2° 22:10	8.82	7%	112.6°
2044-09-24 Sat	100	—	unknown	20:50–04:25 (good, 7.58 h)	87.2° 22:05	8.87	13%	106.8°
2044-09-25 Sun	100	—	unknown	20:50–04:20 (good, 7.5 h)	87.2° 22:00	8.92	21%	100.6°
2044-09-26 Mon	100	—	unknown	20:45–04:15 (good, 7.5 h)	87.2° 21:55	8.97	29%	94.1°
2044-09-27 Tue	100	—	unknown	20:45–04:15 (good, 7.5 h)	87.2° 21:55	9.02	38%	87.6°
2044-09-28 Wed	100	—	unknown	20:40–04:10 (good, 7.5 h)	87.2° 21:50	9.07	48%	81.3°
2044-09-29 Thu	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.2° 21:45	9.11	57%	75.2°
2044-09-30 Fri	95	—	unknown	20:40–04:00 (good, 7.33 h)	87.2° 21:40	9.16	66%	69.7°
2044-10-01 Sat	88	—	unknown	20:35–03:55 (good, 7.33 h)	87.2° 21:35	9.21	75%	64.8°
2044-10-02 Sun	80	—	unknown	20:35–03:55 (good, 7.33 h)	87.2° 21:35	9.26	83%	60.9°
2044-10-03 Mon	60	—	unknown	20:35–20:50 (good, 0.25 h)	87.2° 21:30	9.31	90%	58.3°
2044-10-04 Tue	58	—	unknown	20:30–04:10 (marginal, 7.67 h)	87.2° 21:25	9.35	95%	57.3°
2044-10-05 Wed	55	—	unknown	20:30–03:55 (marginal, 7.42 h)	87.2° 21:20	9.4	99%	58.1°
2044-10-06 Thu	57	—	unknown	20:30–20:35 (good, 0.08 h)	87.2° 21:15	9.45	100%	60.8°
2044-10-07 Fri	65	—	unknown	20:25–21:30 (good, 1.08 h)	87.2° 21:15	9.49	99%	65.2°
2044-10-08 Sat	71	—	unknown	20:25–23:10 (good, 2.75 h)	87.2° 21:10	9.54	96%	71.0°
2044-10-09 Sun	78	—	unknown	20:25–00:40 (good, 4.25 h)	87.2° 21:05	9.58	90%	77.8°
2044-10-10 Mon	100	—	unknown	20:20–01:55 (good, 5.58 h)	87.2° 21:00	9.63	82%	85.2°
2044-10-11 Tue	100	—	unknown	20:20–02:50 (good, 6.5 h)	87.2° 21:00	9.67	72%	92.9°
2044-10-12 Wed	100	—	unknown	20:20–02:55 (good, 6.58 h)	87.2° 20:55	9.72	61%	100.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-09-13&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.