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: 07-25 (100), 07-26 (100), 07-27 (100), 07-28 (100), 07-29 (100) — by astronomy; check the weather when the night is within four days.

2041-07-25astronomy score per night — click a bar for that night2041-08-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-07-25 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:05	5.49	4%	102.0°
2041-07-26 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:00	5.54	1%	107.0°
2041-07-27 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:55	5.6	0%	111.3°
2041-07-28 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:55	5.65	1%	114.7°
2041-07-29 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:50	5.7	3%	117.0°
2041-07-30 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:45	5.76	8%	118.1°
2041-07-31 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:40	5.81	13%	117.9°
2041-08-01 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:40	5.87	20%	116.5°
2041-08-02 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:35	5.92	28%	113.8°
2041-08-03 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:30	5.98	38%	110.0°
2041-08-04 Sun	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:25	6.03	47%	105.4°
2041-08-05 Mon	100	—	unknown	22:25–04:30 (good, 6.08 h)	87.2° 01:20	6.09	57%	99.9°
2041-08-06 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:20	6.15	68%	93.9°
2041-08-07 Wed	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:15	6.2	77%	87.6°
2041-08-08 Thu	100	—	unknown	22:20–04:35 (good, 6.25 h)	87.2° 01:10	6.26	86%	81.1°
2041-08-09 Fri	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:05	6.32	93%	74.9°
2041-08-10 Sat	70	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:00	6.38	98%	69.3°
2041-08-11 Sun	66	—	unknown	22:15–01:15 (good, 3.0 h)	87.2° 01:00	6.43	100%	65.0°
2041-08-12 Mon	67	—	unknown	22:15–00:10 (good, 1.92 h)	87.2° 00:55	6.49	99%	62.4°
2041-08-13 Tue	71	—	unknown	22:10–00:40 (good, 2.5 h)	87.2° 00:50	6.55	95%	61.8°
2041-08-14 Wed	75	—	unknown	22:10–02:05 (good, 3.92 h)	87.2° 00:45	6.61	88%	63.4°
2041-08-15 Thu	100	—	unknown	22:10–03:55 (good, 5.75 h)	87.2° 00:45	6.66	79%	66.7°
2041-08-16 Fri	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:40	6.72	69%	71.4°
2041-08-17 Sat	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:35	6.78	59%	76.9°
2041-08-18 Sun	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:30	6.84	48%	82.8°
2041-08-19 Mon	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.89	38%	88.9°
2041-08-20 Tue	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.95	28%	94.9°
2041-08-21 Wed	100	—	unknown	21:55–04:55 (good, 7.0 h)	87.2° 00:20	7.01	20%	100.5°
2041-08-22 Thu	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.07	12%	105.7°
2041-08-23 Fri	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:10	7.12	7%	110.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-07-25&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.