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

2045-09-07astronomy score per night — click a bar for that night2045-10-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-09-07 Thu	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:10	7.96	14%	113.4°
2045-09-08 Fri	100	—	unknown	21:20–05:20 (good, 8.0 h)	87.2° 23:10	8.02	7%	119.1°
2045-09-09 Sat	100	—	unknown	21:20–05:25 (good, 8.08 h)	87.2° 23:05	8.07	2%	123.0°
2045-09-10 Sun	100	—	unknown	21:15–05:20 (good, 8.08 h)	87.2° 23:00	8.13	0%	124.3°
2045-09-11 Mon	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.2° 22:55	8.18	1%	123.0°
2045-09-12 Tue	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.1° 22:55	8.23	5%	119.3°
2045-09-13 Wed	100	—	unknown	21:10–05:10 (good, 8.0 h)	87.2° 22:50	8.29	11%	113.9°
2045-09-14 Thu	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.2° 22:45	8.34	20%	107.4°
2045-09-15 Fri	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.2° 22:40	8.39	29%	100.4°
2045-09-16 Sat	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.2° 22:35	8.45	39%	93.2°
2045-09-17 Sun	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.2° 22:35	8.5	49%	86.1°
2045-09-18 Mon	100	—	unknown	21:00–04:50 (good, 7.83 h)	87.2° 22:30	8.55	58%	79.3°
2045-09-19 Tue	100	—	unknown	21:00–04:45 (good, 7.75 h)	87.2° 22:25	8.6	68%	73.0°
2045-09-20 Wed	93	—	unknown	20:55–04:40 (good, 7.75 h)	87.2° 22:20	8.65	76%	67.3°
2045-09-21 Thu	85	—	unknown	20:55–04:35 (good, 7.67 h)	87.2° 22:15	8.7	84%	62.5°
2045-09-22 Fri	73	—	unknown	00:35–01:35 (good, 1.0 h)	87.2° 22:15	8.75	90%	58.7°
2045-09-23 Sat	58	—	unknown	20:50–05:00 (marginal, 8.17 h)	87.2° 22:10	8.81	95%	56.4°
2045-09-24 Sun	57	—	unknown	20:50–04:45 (marginal, 7.92 h)	87.2° 22:05	8.86	98%	55.7°
2045-09-25 Mon	56	—	unknown	20:50–04:30 (marginal, 7.67 h)	87.2° 22:00	8.91	100%	56.6°
2045-09-26 Tue	60	—	unknown	20:45–21:00 (good, 0.25 h)	87.1° 22:00	8.96	100%	59.3°
2045-09-27 Wed	66	—	unknown	20:45–22:00 (good, 1.25 h)	87.2° 21:55	9.0	97%	63.4°
2045-09-28 Thu	72	—	unknown	20:45–23:35 (good, 2.83 h)	87.2° 21:50	9.05	93%	68.8°
2045-09-29 Fri	78	—	unknown	20:40–01:15 (good, 4.58 h)	87.2° 21:45	9.1	87%	75.1°
2045-09-30 Sat	100	—	unknown	20:40–02:20 (good, 5.67 h)	87.2° 21:40	9.15	79%	82.1°
2045-10-01 Sun	100	—	unknown	20:35–03:25 (good, 6.83 h)	87.2° 21:40	9.2	70%	89.5°
2045-10-02 Mon	100	—	unknown	20:35–03:35 (good, 7.0 h)	87.2° 21:35	9.25	59%	97.0°
2045-10-03 Tue	100	—	unknown	20:35–03:40 (good, 7.08 h)	87.2° 21:30	9.29	48%	104.5°
2045-10-04 Wed	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:25	9.34	37%	111.4°
2045-10-05 Thu	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.39	26%	117.4°
2045-10-06 Fri	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.43	17%	121.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-09-07&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.