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: 08-22 (1), 08-23 (1), 08-24 (1) — by astronomy; check the weather when the night is within four days.

2038-07-26astronomy score per night — click a bar for that night2038-08-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-07-26 Mon	0	—	unknown	—	42.9° 10:40	5.53	25%	31.4°
2038-07-27 Tue	0	—	unknown	—	42.9° 10:35	5.58	17%	27.3°
2038-07-28 Wed	0	—	unknown	—	42.9° 10:30	5.64	10%	28.1°
2038-07-29 Thu	0	—	unknown	—	42.9° 10:25	5.69	5%	33.6°
2038-07-30 Fri	0	—	unknown	—	42.9° 10:20	5.74	1%	42.3°
2038-07-31 Sat	0	—	unknown	—	42.9° 10:20	5.8	0%	52.9°
2038-08-01 Sun	0	—	unknown	—	42.9° 10:15	5.85	1%	64.5°
2038-08-02 Mon	0	—	unknown	—	42.9° 10:10	5.91	5%	76.7°
2038-08-03 Tue	0	—	unknown	—	42.9° 10:05	5.96	11%	89.3°
2038-08-04 Wed	0	—	unknown	—	42.9° 10:00	6.02	19%	102.0°
2038-08-05 Thu	0	—	unknown	—	42.9° 10:00	6.08	29%	114.5°
2038-08-06 Fri	0	—	unknown	—	42.9° 09:55	6.13	40%	126.6°
2038-08-07 Sat	0	—	unknown	—	42.9° 09:50	6.19	51%	137.7°
2038-08-08 Sun	0	—	unknown	—	42.9° 09:45	6.25	62%	147.0°
2038-08-09 Mon	0	—	unknown	—	42.9° 09:45	6.3	73%	152.4°
2038-08-10 Tue	0	—	unknown	—	42.9° 09:40	6.36	82%	151.8°
2038-08-11 Wed	0	—	unknown	—	42.9° 09:35	6.42	90%	145.8°
2038-08-12 Thu	0	—	unknown	—	42.9° 09:30	6.47	95%	136.6°
2038-08-13 Fri	0	—	unknown	—	42.9° 09:25	6.53	99%	126.1°
2038-08-14 Sat	0	—	unknown	—	42.9° 09:25	6.59	100%	115.0°
2038-08-15 Sun	0	—	unknown	—	42.9° 09:20	6.65	99%	103.8°
2038-08-16 Mon	0	—	unknown	—	42.9° 09:15	6.7	96%	92.6°
2038-08-17 Tue	0	—	unknown	—	42.9° 09:10	6.76	91%	81.6°
2038-08-18 Wed	0	—	unknown	—	42.9° 09:05	6.82	85%	70.9°
2038-08-19 Thu	0	—	unknown	—	42.9° 09:05	6.88	77%	60.6°
2038-08-20 Fri	0	—	unknown	—	42.9° 09:00	6.94	69%	50.7°
2038-08-21 Sat	0	—	unknown	—	42.9° 08:55	6.99	60%	41.6°
2038-08-22 Sun	1	—	unknown	—	42.9° 08:50	7.05	50%	33.8°
2038-08-23 Mon	1	—	unknown	—	42.9° 08:50	7.11	41%	28.5°
2038-08-24 Tue	1	—	unknown	—	42.9° 08:45	7.16	31%	27.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-07-26&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.