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: 08-17 (100), 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100) — by astronomy; check the weather when the night is within four days.

2044-08-17astronomy score per night — click a bar for that night2044-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-08-17 Wed	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:35	6.79	33%	88.9°
2044-08-18 Thu	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:30	6.85	22%	96.6°
2044-08-19 Fri	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.91	13%	104.2°
2044-08-20 Sat	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:20	6.97	6%	111.1°
2044-08-21 Sun	100	—	unknown	21:55–04:55 (good, 7.0 h)	87.2° 00:20	7.02	2%	116.8°
2044-08-22 Mon	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.08	0%	120.8°
2044-08-23 Tue	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:10	7.14	1%	122.6°
2044-08-24 Wed	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:05	7.2	5%	122.2°
2044-08-25 Thu	100	—	unknown	21:50–05:05 (good, 7.25 h)	87.2° 00:00	7.25	10%	119.7°
2044-08-26 Fri	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 00:00	7.31	18%	115.7°
2044-08-27 Sat	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:55	7.37	27%	110.5°
2044-08-28 Sun	100	—	unknown	21:40–05:05 (good, 7.42 h)	87.2° 23:50	7.42	36%	104.6°
2044-08-29 Mon	100	—	unknown	21:40–05:10 (good, 7.5 h)	87.2° 23:45	7.48	46%	98.3°
2044-08-30 Tue	100	—	unknown	21:40–05:10 (good, 7.5 h)	87.2° 23:45	7.54	55%	91.9°
2044-08-31 Wed	100	—	unknown	21:35–05:10 (good, 7.58 h)	87.2° 23:40	7.59	64%	85.5°
2044-09-01 Thu	100	—	unknown	21:35–05:15 (good, 7.67 h)	87.2° 23:35	7.65	73%	79.3°
2044-09-02 Fri	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:30	7.7	81%	73.3°
2044-09-03 Sat	92	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:25	7.76	88%	68.0°
2044-09-04 Sun	84	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:25	7.81	94%	63.3°
2044-09-05 Mon	61	—	unknown	21:25–21:45 (good, 0.33 h)	87.2° 23:20	7.87	98%	59.8°
2044-09-06 Tue	60	—	unknown	20:50–05:20 (marginal, 8.5 h)	87.2° 23:15	7.92	100%	57.7°
2044-09-07 Wed	61	—	unknown	21:20–21:35 (good, 0.25 h)	87.2° 23:10	7.98	100%	57.3°
2044-09-08 Thu	64	—	unknown	21:20–22:10 (good, 0.83 h)	87.2° 23:05	8.03	98%	58.8°
2044-09-09 Fri	69	—	unknown	21:20–23:10 (good, 1.83 h)	87.2° 23:05	8.09	94%	62.0°
2044-09-10 Sat	75	—	unknown	21:15–01:00 (good, 3.75 h)	87.2° 23:00	8.14	87%	66.8°
2044-09-11 Sun	100	—	unknown	21:15–02:40 (good, 5.42 h)	87.2° 22:55	8.19	79%	72.7°
2044-09-12 Mon	100	—	unknown	21:10–03:55 (good, 6.75 h)	87.2° 22:50	8.25	69%	79.6°
2044-09-13 Tue	100	—	unknown	21:10–04:40 (good, 7.5 h)	87.2° 22:50	8.3	58%	87.0°
2044-09-14 Wed	100	—	unknown	21:10–04:45 (good, 7.58 h)	87.2° 22:45	8.35	47%	94.6°
2044-09-15 Thu	100	—	unknown	21:05–04:50 (good, 7.75 h)	87.2° 22:40	8.41	36%	102.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-08-17&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.