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: 08-13 (100), 08-14 (100), 08-15 (100), 08-16 (100), 08-17 (100) — by astronomy; check the weather when the night is within four days.

2031-08-13astronomy score per night — click a bar for that night2031-09-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-08-13 Wed	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.2° 00:50	6.52	16%	105.9°
2031-08-14 Thu	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:50	6.57	10%	112.2°
2031-08-15 Fri	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:45	6.63	5%	117.9°
2031-08-16 Sat	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:40	6.69	2%	122.5°
2031-08-17 Sun	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:35	6.75	0%	125.7°
2031-08-18 Mon	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:35	6.8	1%	127.2°
2031-08-19 Tue	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:30	6.86	3%	126.8°
2031-08-20 Wed	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.92	7%	124.4°
2031-08-21 Thu	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:20	6.98	14%	120.2°
2031-08-22 Fri	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.03	21%	114.5°
2031-08-23 Sat	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.09	30%	107.6°
2031-08-24 Sun	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:10	7.15	41%	100.0°
2031-08-25 Mon	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:05	7.2	52%	91.8°
2031-08-26 Tue	100	—	unknown	21:50–05:05 (good, 7.25 h)	87.2° 00:00	7.26	63%	83.3°
2031-08-27 Wed	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:55	7.32	74%	74.9°
2031-08-28 Thu	97	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:55	7.37	83%	67.0°
2031-08-29 Fri	89	—	unknown	00:10–05:10 (good, 5.0 h)	87.2° 23:50	7.43	91%	60.3°
2031-08-30 Sat	57	—	unknown	21:40–05:10 (marginal, 7.5 h)	87.2° 23:45	7.49	97%	55.4°
2031-08-31 Sun	55	—	unknown	21:40–05:10 (marginal, 7.5 h)	87.2° 23:40	7.54	100%	52.9°
2031-09-01 Mon	57	—	unknown	21:35–05:10 (marginal, 7.58 h)	87.2° 23:40	7.6	99%	53.2°
2031-09-02 Tue	63	—	unknown	21:35–22:10 (good, 0.58 h)	87.2° 23:35	7.66	97%	56.2°
2031-09-03 Wed	70	—	unknown	21:30–23:40 (good, 2.17 h)	87.2° 23:30	7.71	92%	61.3°
2031-09-04 Thu	77	—	unknown	21:30–02:15 (good, 4.75 h)	87.2° 23:25	7.77	84%	67.7°
2031-09-05 Fri	100	—	unknown	21:30–03:30 (good, 6.0 h)	87.2° 23:20	7.82	76%	74.8°
2031-09-06 Sat	100	—	unknown	21:25–04:45 (good, 7.33 h)	87.2° 23:20	7.88	67%	82.2°
2031-09-07 Sun	100	—	unknown	21:25–05:10 (good, 7.75 h)	87.2° 23:15	7.93	57%	89.7°
2031-09-08 Mon	100	—	unknown	21:20–05:15 (good, 7.92 h)	87.2° 23:10	7.99	48%	97.0°
2031-09-09 Tue	100	—	unknown	21:20–05:15 (good, 7.92 h)	87.2° 23:05	8.04	38%	104.0°
2031-09-10 Wed	100	—	unknown	21:20–05:15 (good, 7.92 h)	87.2° 23:00	8.09	29%	110.6°
2031-09-11 Thu	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.2° 23:00	8.15	21%	116.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-08-13&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.