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: 05-26 (100), 06-09 (100), 06-10 (100), 06-11 (100), 06-12 (100) — by astronomy; check the weather when the night is within four days.

2045-05-26astronomy score per night — click a bar for that night2045-06-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-05-26 Fri	100	—	unknown	00:00–03:50 (good, 3.83 h)	87.2° 06:00	5.02	84%	117.9°
2045-05-27 Sat	90	—	unknown	00:00–03:50 (good, 3.83 h)	87.2° 05:55	4.98	91%	112.7°
2045-05-28 Sun	83	—	unknown	00:00–03:50 (good, 3.83 h)	87.2° 05:55	4.93	96%	106.4°
2045-05-29 Mon	76	—	unknown	00:00–03:50 (good, 3.83 h)	87.2° 05:50	4.89	99%	99.7°
2045-05-30 Tue	69	—	unknown	00:00–03:45 (good, 3.75 h)	87.2° 05:45	4.86	100%	92.6°
2045-05-31 Wed	64	—	unknown	00:00–03:45 (good, 3.75 h)	87.2° 05:40	4.82	98%	85.7°
2045-06-01 Thu	61	—	unknown	23:55–03:45 (good, 3.83 h)	87.1° 05:40	4.78	95%	78.9°
2045-06-02 Fri	66	—	unknown	23:50–03:45 (good, 3.92 h)	87.2° 05:35	4.75	90%	72.7°
2045-06-03 Sat	76	—	unknown	23:15–03:45 (good, 4.5 h)	87.2° 05:30	4.71	84%	67.1°
2045-06-04 Sun	83	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:25	4.68	76%	62.3°
2045-06-05 Mon	89	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:20	4.65	68%	58.8°
2045-06-06 Tue	92	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:20	4.62	59%	56.6°
2045-06-07 Wed	94	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:15	4.6	49%	56.0°
2045-06-08 Thu	97	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:10	4.57	40%	57.1°
2045-06-09 Fri	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:05	4.55	30%	59.9°
2045-06-10 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:00	4.53	21%	64.3°
2045-06-11 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:00	4.51	13%	70.1°
2045-06-12 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:55	4.49	7%	76.9°
2045-06-13 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:50	4.47	2%	84.6°
2045-06-14 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:45	4.46	0%	92.6°
2045-06-15 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 04:40	4.45	1%	100.7°
2045-06-16 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:40	4.44	5%	108.4°
2045-06-17 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:35	4.43	11%	115.1°
2045-06-18 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:30	4.43	20%	120.2°
2045-06-19 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:25	4.42	30%	123.4°
2045-06-20 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:25	4.42	41%	124.1°
2045-06-21 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:20	4.42	52%	122.6°
2045-06-22 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:15	4.43	63%	119.1°
2045-06-23 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:10	4.43	73%	114.1°
2045-06-24 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:05	4.44	82%	108.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-05-26&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.