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: 06-18 (100), 06-19 (100), 06-20 (100), 06-21 (100), 06-22 (100) — by astronomy; check the weather when the night is within four days.

2028-06-18astronomy score per night — click a bar for that night2028-07-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-06-18 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:30	4.43	16%	70.6°
2028-06-19 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:25	4.42	10%	77.6°
2028-06-20 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:20	4.42	4%	85.3°
2028-06-21 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:20	4.42	1%	93.3°
2028-06-22 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:15	4.43	0%	101.5°
2028-06-23 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:10	4.43	2%	109.3°
2028-06-24 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:05	4.44	6%	116.3°
2028-06-25 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:00	4.45	13%	121.8°
2028-06-26 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:00	4.46	22%	125.4°
2028-06-27 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 03:55	4.47	32%	126.5°
2028-06-28 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 03:50	4.49	43%	124.9°
2028-06-29 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:45	4.51	55%	121.1°
2028-06-30 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:40	4.53	66%	115.4°
2028-07-01 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:40	4.55	76%	108.7°
2028-07-02 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:35	4.57	85%	101.2°
2028-07-03 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:30	4.6	92%	93.4°
2028-07-04 Tue	79	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:25	4.62	96%	85.7°
2028-07-05 Wed	71	—	unknown	23:10–03:50 (good, 4.67 h)	87.2° 03:25	4.65	99%	78.2°
2028-07-06 Thu	61	—	unknown	23:10–03:50 (good, 4.67 h)	87.2° 03:20	4.68	100%	71.2°
2028-07-07 Fri	55	—	unknown	23:05–03:50 (good, 4.75 h)	87.3° 03:15	4.71	99%	65.0°
2028-07-08 Sat	54	—	unknown	23:05–01:10 (good, 2.08 h)	87.2° 03:10	4.75	95%	59.9°
2028-07-09 Sun	56	—	unknown	23:05–01:20 (good, 2.25 h)	87.2° 03:05	4.78	90%	56.1°
2028-07-10 Mon	62	—	unknown	23:05–02:05 (good, 3.0 h)	87.2° 03:05	4.82	84%	54.0°
2028-07-11 Tue	92	—	unknown	23:05–03:25 (good, 4.33 h)	87.2° 03:00	4.86	77%	53.6°
2028-07-12 Wed	95	—	unknown	23:05–03:55 (good, 4.83 h)	87.3° 02:55	4.9	68%	55.0°
2028-07-13 Thu	99	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:50	4.94	59%	58.1°
2028-07-14 Fri	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:45	4.98	49%	62.5°
2028-07-15 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:45	5.02	40%	68.2°
2028-07-16 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:40	5.06	30%	74.8°
2028-07-17 Mon	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.2° 02:35	5.11	21%	82.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-06-18&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.