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 Great Orion Nebula: 04-08 (2), 04-09 (1), 04-10 (1), 04-11 (1) — by astronomy; check the weather when the night is within four days.

2038-04-08astronomy score per night — click a bar for that night2038-05-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-04-08 Thu	2	—	unknown	21:35–21:40 (marginal, 0.08 h)	42.9° 17:50	7.69	16%	30.5°
2038-04-09 Fri	1	—	unknown	—	42.9° 17:45	7.63	23%	26.9°
2038-04-10 Sat	1	—	unknown	—	42.9° 17:40	7.57	32%	28.2°
2038-04-11 Sun	1	—	unknown	—	42.9° 17:40	7.52	42%	34.0°
2038-04-12 Mon	0	—	unknown	—	42.9° 17:35	7.46	52%	42.8°
2038-04-13 Tue	0	—	unknown	—	42.9° 17:30	7.4	62%	53.4°
2038-04-14 Wed	0	—	unknown	—	42.9° 17:25	7.35	73%	65.1°
2038-04-15 Thu	0	—	unknown	—	42.9° 17:25	7.29	82%	77.7°
2038-04-16 Fri	0	—	unknown	—	42.9° 17:20	7.23	90%	90.7°
2038-04-17 Sat	0	—	unknown	—	42.9° 17:15	7.17	96%	104.1°
2038-04-18 Sun	0	—	unknown	—	42.9° 17:10	7.11	99%	117.4°
2038-04-19 Mon	0	—	unknown	—	42.9° 17:05	7.06	100%	130.2°
2038-04-20 Tue	0	—	unknown	—	42.9° 17:05	7.0	96%	141.7°
2038-04-21 Wed	0	—	unknown	—	42.9° 17:00	6.94	91%	150.1°
2038-04-22 Thu	0	—	unknown	—	42.9° 16:55	6.88	83%	153.1°
2038-04-23 Fri	0	—	unknown	—	42.9° 16:50	6.82	74%	149.6°
2038-04-24 Sat	0	—	unknown	—	42.9° 16:45	6.77	64%	141.7°
2038-04-25 Sun	0	—	unknown	—	42.9° 16:45	6.71	53%	132.0°
2038-04-26 Mon	0	—	unknown	—	42.9° 16:40	6.65	43%	121.5°
2038-04-27 Tue	0	—	unknown	—	42.9° 16:35	6.59	34%	110.8°
2038-04-28 Wed	0	—	unknown	—	42.9° 16:30	6.53	25%	100.1°
2038-04-29 Thu	0	—	unknown	—	42.9° 16:30	6.47	17%	89.5°
2038-04-30 Fri	0	—	unknown	—	42.9° 16:25	6.42	11%	78.9°
2038-05-01 Sat	0	—	unknown	—	42.9° 16:20	6.36	6%	68.5°
2038-05-02 Sun	0	—	unknown	—	42.9° 16:15	6.3	2%	58.3°
2038-05-03 Mon	0	—	unknown	—	42.9° 16:10	6.24	0%	48.5°
2038-05-04 Tue	0	—	unknown	—	42.9° 16:10	6.19	0%	39.5°
2038-05-05 Wed	0	—	unknown	—	42.9° 16:05	6.13	2%	32.1°
2038-05-06 Thu	0	—	unknown	—	42.9° 16:00	6.07	6%	27.5°
2038-05-07 Fri	0	—	unknown	—	42.9° 15:55	6.01	11%	27.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-04-08&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.