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: 06-15 (100), 06-16 (100), 06-17 (100), 06-18 (100), 06-19 (100) — by astronomy; check the weather when the night is within four days.

2040-06-15astronomy score per night — click a bar for that night2040-07-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-06-15 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:40	4.45	31%	117.0°
2040-06-16 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:40	4.44	40%	117.2°
2040-06-17 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:35	4.43	50%	116.0°
2040-06-18 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:30	4.43	61%	113.4°
2040-06-19 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:25	4.42	71%	109.5°
2040-06-20 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:20	4.42	80%	104.6°
2040-06-21 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:20	4.42	88%	98.7°
2040-06-22 Fri	82	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:15	4.43	95%	92.1°
2040-06-23 Sat	74	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:10	4.43	99%	85.3°
2040-06-24 Sun	65	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:05	4.44	100%	78.6°
2040-06-25 Mon	61	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:00	4.45	98%	72.6°
2040-06-26 Tue	64	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:00	4.46	93%	67.7°
2040-06-27 Wed	91	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 03:55	4.48	86%	64.3°
2040-06-28 Thu	95	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 03:50	4.49	76%	62.8°
2040-06-29 Fri	99	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:45	4.51	66%	63.1°
2040-06-30 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:45	4.53	55%	65.0°
2040-07-01 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:40	4.55	45%	68.2°
2040-07-02 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:35	4.57	34%	72.5°
2040-07-03 Tue	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:30	4.6	25%	77.4°
2040-07-04 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:25	4.63	17%	82.8°
2040-07-05 Thu	100	—	unknown	23:10–03:50 (good, 4.67 h)	87.2° 03:25	4.66	10%	88.3°
2040-07-06 Fri	100	—	unknown	23:10–03:50 (good, 4.67 h)	87.2° 03:20	4.69	5%	93.8°
2040-07-07 Sat	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.2° 03:15	4.72	2%	99.1°
2040-07-08 Sun	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.2° 03:10	4.75	0%	104.1°
2040-07-09 Mon	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.2° 03:05	4.79	0%	108.6°
2040-07-10 Tue	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.2° 03:05	4.82	2%	112.3°
2040-07-11 Wed	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.2° 03:00	4.86	6%	115.2°
2040-07-12 Thu	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.2° 02:55	4.9	11%	116.9°
2040-07-13 Fri	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:50	4.94	18%	117.4°
2040-07-14 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:45	4.98	26%	116.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-06-15&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.