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: 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100), 09-05 (100) — by astronomy; check the weather when the night is within four days.

2029-09-01astronomy score per night — click a bar for that night2029-09-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-09-01 Sat	100	—	unknown	21:35–05:10 (good, 7.58 h)	87.2° 23:35	7.63	43%	93.6°
2029-09-02 Sun	100	—	unknown	21:35–05:15 (good, 7.67 h)	87.2° 23:30	7.68	33%	101.0°
2029-09-03 Mon	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:30	7.74	24%	108.2°
2029-09-04 Tue	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:25	7.79	16%	115.0°
2029-09-05 Wed	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:20	7.85	8%	120.8°
2029-09-06 Thu	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.9	3%	125.1°
2029-09-07 Fri	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:10	7.96	0%	127.1°
2029-09-08 Sat	100	—	unknown	21:20–05:20 (good, 8.0 h)	87.2° 23:10	8.01	0%	126.4°
2029-09-09 Sun	100	—	unknown	21:20–05:25 (good, 8.08 h)	87.2° 23:05	8.07	3%	122.9°
2029-09-10 Mon	100	—	unknown	21:15–05:20 (good, 8.08 h)	87.2° 23:00	8.12	9%	117.1°
2029-09-11 Tue	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.2° 22:55	8.17	17%	109.9°
2029-09-12 Wed	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.2° 22:50	8.23	27%	101.7°
2029-09-13 Thu	100	—	unknown	21:10–05:10 (good, 8.0 h)	87.2° 22:50	8.28	37%	93.2°
2029-09-14 Fri	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.2° 22:45	8.33	48%	84.8°
2029-09-15 Sat	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.2° 22:40	8.39	60%	76.7°
2029-09-16 Sun	99	—	unknown	21:05–04:55 (good, 7.83 h)	87.2° 22:35	8.44	70%	69.4°
2029-09-17 Mon	91	—	unknown	21:05–04:55 (good, 7.83 h)	87.2° 22:35	8.49	79%	63.0°
2029-09-18 Tue	83	—	unknown	23:15–04:50 (good, 5.58 h)	87.2° 22:30	8.54	86%	57.9°
2029-09-19 Wed	59	—	unknown	21:00–05:20 (marginal, 8.33 h)	87.2° 22:25	8.59	93%	54.4°
2029-09-20 Thu	54	—	unknown	21:00–05:05 (marginal, 8.08 h)	87.2° 22:20	8.65	97%	52.9°
2029-09-21 Fri	53	—	unknown	20:55–04:50 (marginal, 7.92 h)	87.2° 22:15	8.7	99%	53.3°
2029-09-22 Sat	55	—	unknown	20:55–04:35 (marginal, 7.67 h)	87.2° 22:15	8.75	100%	55.6°
2029-09-23 Sun	63	—	unknown	20:50–21:20 (good, 0.5 h)	87.2° 22:10	8.8	98%	59.5°
2029-09-24 Mon	68	—	unknown	20:50–22:35 (good, 1.75 h)	87.2° 22:05	8.85	95%	64.6°
2029-09-25 Tue	74	—	unknown	20:50–00:35 (good, 3.75 h)	87.2° 22:00	8.9	91%	70.6°
2029-09-26 Wed	100	—	unknown	20:45–01:45 (good, 5.0 h)	87.2° 21:55	8.95	84%	77.2°
2029-09-27 Thu	100	—	unknown	20:45–02:55 (good, 6.17 h)	87.2° 21:55	9.0	77%	84.2°
2029-09-28 Fri	100	—	unknown	20:45–03:40 (good, 6.92 h)	87.2° 21:50	9.05	69%	91.5°
2029-09-29 Sat	100	—	unknown	20:40–03:45 (good, 7.08 h)	87.2° 21:45	9.1	59%	98.7°
2029-09-30 Sun	100	—	unknown	20:40–03:50 (good, 7.17 h)	87.2° 21:40	9.14	50%	105.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-09-01&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.