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), 05-27 (100), 05-28 (100), 05-29 (100), 05-30 (100) — by astronomy; check the weather when the night is within four days.

2041-05-26astronomy score per night — click a bar for that night2041-06-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-05-26 Sun	100	—	unknown	23:45–03:50 (good, 4.08 h)	87.2° 06:00	5.02	10%	70.7°
2041-05-27 Mon	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:55	4.98	5%	75.9°
2041-05-28 Tue	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:55	4.94	1%	81.7°
2041-05-29 Wed	100	—	unknown	23:35–03:50 (good, 4.25 h)	87.2° 05:50	4.9	0%	87.8°
2041-05-30 Thu	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.2° 05:45	4.86	1%	93.8°
2041-05-31 Fri	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.2° 05:40	4.82	4%	99.6°
2041-06-01 Sat	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.2° 05:40	4.78	9%	104.9°
2041-06-02 Sun	100	—	unknown	23:20–03:45 (good, 4.42 h)	87.2° 05:35	4.75	16%	109.5°
2041-06-03 Mon	100	—	unknown	23:20–03:45 (good, 4.42 h)	87.2° 05:30	4.71	23%	113.2°
2041-06-04 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 05:25	4.68	32%	116.0°
2041-06-05 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:20	4.65	41%	117.5°
2041-06-06 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:20	4.62	50%	117.8°
2041-06-07 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:15	4.6	60%	116.8°
2041-06-08 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:10	4.57	69%	114.5°
2041-06-09 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:05	4.55	78%	111.0°
2041-06-10 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:00	4.53	86%	106.5°
2041-06-11 Tue	86	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:00	4.51	92%	101.1°
2041-06-12 Wed	80	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:55	4.49	97%	95.0°
2041-06-13 Thu	73	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:50	4.47	100%	88.6°
2041-06-14 Fri	66	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:45	4.46	100%	82.1°
2041-06-15 Sat	63	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:40	4.45	97%	75.8°
2041-06-16 Sun	79	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:40	4.44	92%	70.3°
2041-06-17 Mon	89	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:35	4.43	84%	65.9°
2041-06-18 Tue	93	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:30	4.43	74%	63.1°
2041-06-19 Wed	97	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:25	4.42	64%	62.1°
2041-06-20 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:25	4.42	52%	62.9°
2041-06-21 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:20	4.42	41%	65.5°
2041-06-22 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:15	4.43	30%	69.5°
2041-06-23 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:10	4.43	21%	74.4°
2041-06-24 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:05	4.44	13%	80.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-05-26&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.