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.

2039-09-07astronomy score per night — click a bar for that night2039-10-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-09-07 Wed	100	—	unknown	21:25–04:00 (good, 6.58 h)	87.2° 23:15	7.93	74%	80.0°
2039-09-08 Thu	100	—	unknown	21:20–04:55 (good, 7.58 h)	87.2° 23:10	7.99	65%	85.4°
2039-09-09 Fri	100	—	unknown	21:20–05:05 (good, 7.75 h)	87.2° 23:05	8.04	56%	90.9°
2039-09-10 Sat	100	—	unknown	21:20–05:05 (good, 7.75 h)	87.2° 23:00	8.1	47%	96.3°
2039-09-11 Sun	100	—	unknown	21:15–05:10 (good, 7.92 h)	87.2° 23:00	8.15	37%	101.5°
2039-09-12 Mon	100	—	unknown	21:15–05:10 (good, 7.92 h)	87.2° 22:55	8.2	28%	106.4°
2039-09-13 Tue	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.2° 22:50	8.26	20%	110.7°
2039-09-14 Wed	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.2° 22:45	8.31	13%	114.1°
2039-09-15 Thu	100	—	unknown	21:10–05:00 (good, 7.83 h)	87.2° 22:45	8.36	7%	116.5°
2039-09-16 Fri	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.2° 22:40	8.42	3%	117.5°
2039-09-17 Sat	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.2° 22:35	8.47	0%	117.0°
2039-09-18 Sun	100	—	unknown	21:00–04:50 (good, 7.83 h)	87.2° 22:30	8.52	1%	114.8°
2039-09-19 Mon	100	—	unknown	21:00–04:45 (good, 7.75 h)	87.2° 22:25	8.57	3%	111.1°
2039-09-20 Tue	100	—	unknown	21:00–04:45 (good, 7.75 h)	87.2° 22:25	8.62	8%	106.2°
2039-09-21 Wed	100	—	unknown	20:55–04:40 (good, 7.75 h)	87.2° 22:20	8.68	16%	100.4°
2039-09-22 Thu	100	—	unknown	20:55–04:35 (good, 7.67 h)	87.2° 22:15	8.73	25%	94.0°
2039-09-23 Fri	100	—	unknown	20:55–04:30 (good, 7.58 h)	87.2° 22:10	8.78	36%	87.4°
2039-09-24 Sat	100	—	unknown	20:50–04:30 (good, 7.67 h)	87.2° 22:05	8.83	47%	81.0°
2039-09-25 Sun	100	—	unknown	20:50–04:25 (good, 7.58 h)	87.2° 22:05	8.88	58%	75.1°
2039-09-26 Mon	96	—	unknown	20:45–04:20 (good, 7.58 h)	87.2° 22:00	8.93	69%	70.0°
2039-09-27 Tue	88	—	unknown	20:45–04:15 (good, 7.5 h)	87.2° 21:55	8.98	79%	66.0°
2039-09-28 Wed	78	—	unknown	20:45–04:10 (good, 7.42 h)	87.2° 21:50	9.03	87%	63.5°
2039-09-29 Thu	64	—	unknown	20:40–22:05 (good, 1.42 h)	87.2° 21:50	9.08	94%	62.5°
2039-09-30 Fri	63	—	unknown	20:40–21:35 (good, 0.92 h)	87.2° 21:45	9.12	98%	63.2°
2039-10-01 Sat	65	—	unknown	20:40–21:55 (good, 1.25 h)	87.2° 21:40	9.17	100%	65.4°
2039-10-02 Sun	69	—	unknown	20:35–22:40 (good, 2.08 h)	87.2° 21:35	9.22	100%	68.8°
2039-10-03 Mon	73	—	unknown	20:35–23:55 (good, 3.33 h)	87.2° 21:30	9.27	97%	73.1°
2039-10-04 Tue	78	—	unknown	20:35–00:55 (good, 4.33 h)	87.2° 21:30	9.32	93%	78.1°
2039-10-05 Wed	100	—	unknown	20:30–01:45 (good, 5.25 h)	87.2° 21:25	9.36	87%	83.4°
2039-10-06 Thu	100	—	unknown	20:30–02:35 (good, 6.08 h)	87.2° 21:20	9.41	80%	88.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-09-07&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.