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: 09-30 (100), 10-01 (100), 10-02 (100), 10-03 (100), 10-04 (100) — by astronomy; check the weather when the night is within four days.

2045-09-24astronomy score per night — click a bar for that night2045-10-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2045-10-07 Sat	100	—	unknown	20:25–03:35 (good, 7.17 h)	87.2° 21:15	9.48	9%	124.2°
2045-10-08 Sun	100	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.53	3%	123.9°
2045-10-09 Mon	100	—	unknown	20:25–03:25 (good, 7.0 h)	87.2° 21:05	9.57	0%	121.2°
2045-10-10 Tue	100	—	unknown	20:20–03:25 (good, 7.08 h)	87.1° 21:00	9.62	0%	116.4°
2045-10-11 Wed	100	—	unknown	20:20–03:20 (good, 7.0 h)	87.2° 21:00	9.66	3%	110.2°
2045-10-12 Thu	100	—	unknown	20:20–03:15 (good, 6.92 h)	87.2° 20:55	9.71	8%	103.2°
2045-10-13 Fri	100	—	unknown	20:15–03:10 (good, 6.92 h)	87.2° 20:50	9.75	15%	95.8°
2045-10-14 Sat	100	—	unknown	20:15–03:05 (good, 6.83 h)	87.2° 20:45	9.79	23%	88.5°
2045-10-15 Sun	100	—	unknown	20:15–03:05 (good, 6.83 h)	87.2° 20:45	9.84	32%	81.4°
2045-10-16 Mon	100	—	unknown	20:15–03:00 (good, 6.75 h)	87.2° 20:40	9.88	42%	74.8°
2045-10-17 Tue	96	—	unknown	20:10–02:55 (good, 6.75 h)	87.2° 20:35	9.92	51%	68.8°
2045-10-18 Wed	88	—	unknown	20:10–02:50 (good, 6.67 h)	87.2° 20:30	9.97	61%	63.7°
2045-10-19 Thu	81	—	unknown	20:10–02:45 (good, 6.58 h)	87.2° 20:25	10.01	70%	59.6°
2045-10-20 Fri	63	—	unknown	20:05–00:45 (good, 4.67 h)	87.2° 20:25	10.05	78%	56.8°
2045-10-21 Sat	58	—	unknown	20:05–03:10 (marginal, 7.08 h)	87.2° 20:20	10.09	85%	55.6°
2045-10-22 Sun	51	—	unknown	20:05–02:55 (marginal, 6.83 h)	87.2° 20:15	10.13	91%	56.1°
2045-10-23 Mon	47	—	unknown	20:05–02:40 (marginal, 6.58 h)	87.2° 20:10	10.17	96%	58.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-09-24&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.