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: 09-22 (100), 09-23 (100), 09-24 (100), 09-25 (100), 09-26 (100) — by astronomy; check the weather when the night is within four days.

2043-09-16astronomy score per night — click a bar for that night2043-10-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-09-16 Wed	67	—	unknown	21:05–22:05 (good, 1.0 h)	87.2° 22:40	8.42	94%	61.3°
2043-09-17 Thu	60	—	unknown	21:05–21:15 (good, 0.17 h)	87.2° 22:35	8.47	98%	59.3°
2043-09-18 Fri	61	—	unknown	21:00–21:20 (good, 0.33 h)	87.2° 22:30	8.52	100%	59.2°
2043-09-19 Sat	64	—	unknown	21:00–21:50 (good, 0.83 h)	87.2° 22:25	8.57	99%	61.2°
2043-09-20 Sun	69	—	unknown	21:00–23:00 (good, 2.0 h)	87.2° 22:25	8.63	95%	65.0°
2043-09-21 Mon	75	—	unknown	20:55–01:05 (good, 4.17 h)	87.2° 22:20	8.68	89%	70.5°
2043-09-22 Tue	100	—	unknown	20:55–02:15 (good, 5.33 h)	87.2° 22:15	8.73	81%	77.0°
2043-09-23 Wed	100	—	unknown	20:55–03:30 (good, 6.58 h)	87.2° 22:10	8.78	71%	84.2°
2043-09-24 Thu	100	—	unknown	20:50–04:05 (good, 7.25 h)	87.2° 22:05	8.83	60%	91.5°
2043-09-25 Fri	100	—	unknown	20:50–04:10 (good, 7.33 h)	87.2° 22:05	8.88	48%	98.7°
2043-09-26 Sat	100	—	unknown	20:45–04:10 (good, 7.42 h)	87.2° 22:00	8.93	37%	105.3°
2043-09-27 Sun	100	—	unknown	20:45–04:10 (good, 7.42 h)	87.2° 21:55	8.98	27%	111.2°
2043-09-28 Mon	100	—	unknown	20:45–04:10 (good, 7.42 h)	87.2° 21:50	9.03	18%	115.9°
2043-09-29 Tue	100	—	unknown	20:40–04:10 (good, 7.5 h)	87.2° 21:50	9.08	10%	119.2°
2043-09-30 Wed	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.2° 21:45	9.13	5%	120.8°
2043-10-01 Thu	100	—	unknown	20:40–04:00 (good, 7.33 h)	87.2° 21:40	9.17	2%	120.8°
2043-10-02 Fri	100	—	unknown	20:35–03:55 (good, 7.33 h)	87.2° 21:35	9.22	0%	119.0°
2043-10-03 Sat	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.27	1%	115.9°
2043-10-04 Sun	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.32	3%	111.7°
2043-10-05 Mon	100	—	unknown	20:30–03:45 (good, 7.25 h)	87.2° 21:25	9.36	7%	106.6°
2043-10-06 Tue	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.41	13%	101.1°
2043-10-07 Wed	100	—	unknown	20:30–03:35 (good, 7.08 h)	87.2° 21:15	9.46	20%	95.1°
2043-10-08 Thu	100	—	unknown	20:25–03:35 (good, 7.17 h)	87.2° 21:10	9.5	28%	89.1°
2043-10-09 Fri	100	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.55	37%	83.0°
2043-10-10 Sat	100	—	unknown	20:25–03:25 (good, 7.0 h)	87.2° 21:05	9.59	46%	77.1°
2043-10-11 Sun	98	—	unknown	20:20–03:20 (good, 7.0 h)	87.2° 21:00	9.64	56%	71.6°
2043-10-12 Mon	89	—	unknown	20:20–03:15 (good, 6.92 h)	87.2° 20:55	9.68	66%	66.6°
2043-10-13 Tue	81	—	unknown	20:20–03:15 (good, 6.92 h)	87.2° 20:55	9.73	75%	62.6°
2043-10-14 Wed	64	—	unknown	20:15–00:35 (good, 4.33 h)	87.2° 20:50	9.77	84%	59.9°
2043-10-15 Thu	60	—	unknown	19:45–03:30 (marginal, 7.75 h)	87.2° 20:45	9.82	91%	59.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-09-16&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.