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: 09-20 (100), 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100) — by astronomy; check the weather when the night is within four days.

2035-09-16astronomy score per night — click a bar for that night2035-10-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-09-16 Sun	60	—	unknown	21:05–21:10 (good, 0.08 h)	87.2° 22:40	8.42	100%	58.7°
2035-09-17 Mon	64	—	unknown	21:05–21:55 (good, 0.83 h)	87.2° 22:35	8.47	100%	61.6°
2035-09-18 Tue	69	—	unknown	21:00–23:05 (good, 2.08 h)	87.2° 22:30	8.52	98%	66.1°
2035-09-19 Wed	75	—	unknown	21:00–01:05 (good, 4.08 h)	87.2° 22:25	8.57	94%	71.9°
2035-09-20 Thu	100	—	unknown	21:00–02:15 (good, 5.25 h)	87.2° 22:25	8.62	87%	78.6°
2035-09-21 Fri	100	—	unknown	20:55–03:25 (good, 6.5 h)	87.2° 22:20	8.67	79%	85.8°
2035-09-22 Sat	100	—	unknown	20:55–04:05 (good, 7.17 h)	87.2° 22:15	8.73	69%	93.4°
2035-09-23 Sun	100	—	unknown	20:55–04:15 (good, 7.33 h)	87.2° 22:10	8.78	58%	100.8°
2035-09-24 Mon	100	—	unknown	20:50–04:15 (good, 7.42 h)	87.2° 22:05	8.83	46%	107.7°
2035-09-25 Tue	100	—	unknown	20:50–04:20 (good, 7.5 h)	87.2° 22:05	8.88	35%	113.8°
2035-09-26 Wed	100	—	unknown	20:45–04:15 (good, 7.5 h)	87.2° 22:00	8.93	25%	118.6°
2035-09-27 Thu	100	—	unknown	20:45–04:15 (good, 7.5 h)	87.2° 21:55	8.98	16%	121.6°
2035-09-28 Fri	100	—	unknown	20:45–04:10 (good, 7.42 h)	87.2° 21:50	9.02	8%	122.5°
2035-09-29 Sat	100	—	unknown	20:40–04:10 (good, 7.5 h)	87.2° 21:50	9.07	3%	121.3°
2035-09-30 Sun	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.2° 21:45	9.12	0%	118.2°
2035-10-01 Mon	100	—	unknown	20:40–04:00 (good, 7.33 h)	87.2° 21:40	9.17	0%	113.5°
2035-10-02 Tue	100	—	unknown	20:35–03:55 (good, 7.33 h)	87.2° 21:35	9.22	2%	107.9°
2035-10-03 Wed	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.27	6%	101.6°
2035-10-04 Thu	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.31	12%	95.0°
2035-10-05 Fri	100	—	unknown	20:30–03:45 (good, 7.25 h)	87.2° 21:25	9.36	19%	88.4°
2035-10-06 Sat	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.41	27%	82.0°
2035-10-07 Sun	100	—	unknown	20:30–03:35 (good, 7.08 h)	87.2° 21:15	9.45	36%	76.0°
2035-10-08 Mon	100	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.5	45%	70.4°
2035-10-09 Tue	96	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.55	55%	65.5°
2035-10-10 Wed	90	—	unknown	20:25–03:25 (good, 7.0 h)	87.2° 21:05	9.59	64%	61.6°
2035-10-11 Thu	83	—	unknown	20:20–03:20 (good, 7.0 h)	87.2° 21:00	9.64	73%	58.9°
2035-10-12 Fri	63	—	unknown	20:20–01:20 (good, 5.0 h)	87.2° 20:55	9.68	81%	57.6°
2035-10-13 Sat	60	—	unknown	20:20–20:25 (good, 0.08 h)	87.2° 20:55	9.73	89%	58.1°
2035-10-14 Sun	60	—	unknown	20:15–20:20 (good, 0.08 h)	87.2° 20:50	9.77	94%	60.3°
2035-10-15 Mon	61	—	unknown	20:15–20:50 (good, 0.58 h)	87.2° 20:45	9.81	98%	64.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-09-16&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.