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: 11-04 (89), 11-05 (89), 11-06 (89), 11-21 (89), 11-22 (89) — by astronomy; check the weather when the night is within four days.

2038-11-04astronomy score per night — click a bar for that night2038-12-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-11-04 Thu	89	—	unknown	23:55–05:25 (good, 5.5 h)	42.9° 03:00	10.61	60%	112.3°
2038-11-05 Fri	89	—	unknown	23:55–05:25 (good, 5.5 h)	42.9° 02:55	10.65	70%	101.4°
2038-11-06 Sat	89	—	unknown	00:05–05:30 (good, 5.42 h)	42.9° 02:55	10.68	79%	90.5°
2038-11-07 Sun	88	—	unknown	00:40–05:30 (good, 4.83 h)	42.9° 02:50	10.71	86%	79.8°
2038-11-08 Mon	86	—	unknown	02:25–05:30 (good, 3.08 h)	42.9° 02:45	10.75	92%	69.4°
2038-11-09 Tue	69	—	unknown	05:15–05:30 (good, 0.25 h)	42.9° 02:40	10.78	96%	59.2°
2038-11-10 Wed	34	—	unknown	23:50–05:30 (marginal, 5.67 h)	42.9° 02:35	10.81	99%	49.5°
2038-11-11 Thu	22	—	unknown	01:50–05:35 (marginal, 3.75 h)	42.9° 02:35	10.84	100%	40.6°
2038-11-12 Fri	15	—	unknown	04:10–05:35 (marginal, 1.42 h)	42.9° 02:30	10.87	99%	33.3°
2038-11-13 Sat	12	—	unknown	—	42.9° 02:25	10.9	96%	28.6°
2038-11-14 Sun	13	—	unknown	—	42.9° 02:20	10.93	92%	28.2°
2038-11-15 Mon	19	—	unknown	23:10–03:00 (marginal, 3.83 h)	42.9° 02:15	10.96	86%	32.2°
2038-11-16 Tue	32	—	unknown	22:45–05:20 (marginal, 6.58 h)	42.9° 02:15	10.99	79%	39.4°
2038-11-17 Wed	49	—	unknown	22:25–05:35 (marginal, 7.17 h)	42.9° 02:10	11.02	70%	48.7°
2038-11-18 Thu	65	—	unknown	23:15–03:05 (good, 3.83 h)	42.9° 02:05	11.04	60%	59.0°
2038-11-19 Fri	81	—	unknown	22:50–04:50 (good, 6.0 h)	42.9° 02:00	11.07	50%	70.2°
2038-11-20 Sat	86	—	unknown	22:45–05:00 (good, 6.25 h)	42.9° 02:00	11.1	39%	82.0°
2038-11-21 Sun	89	—	unknown	22:40–05:05 (good, 6.42 h)	42.9° 01:55	11.12	29%	94.3°
2038-11-22 Mon	89	—	unknown	22:35–05:05 (good, 6.5 h)	42.9° 01:50	11.15	19%	106.9°
2038-11-23 Tue	89	—	unknown	22:30–05:05 (good, 6.58 h)	42.9° 01:45	11.17	10%	119.6°
2038-11-24 Wed	89	—	unknown	22:30–05:00 (good, 6.5 h)	42.9° 01:40	11.19	4%	131.8°
2038-11-25 Thu	89	—	unknown	22:25–04:55 (good, 6.5 h)	42.9° 01:40	11.21	1%	142.8°
2038-11-26 Fri	89	—	unknown	22:20–04:55 (good, 6.58 h)	42.9° 01:35	11.24	0%	150.4°
2038-11-27 Sat	89	—	unknown	22:15–04:50 (good, 6.58 h)	42.9° 01:30	11.26	3%	151.9°
2038-11-28 Sun	89	—	unknown	22:10–04:45 (good, 6.58 h)	42.9° 01:25	11.28	8%	146.7°
2038-11-29 Mon	89	—	unknown	22:10–04:40 (good, 6.5 h)	42.9° 01:20	11.3	15%	137.5°
2038-11-30 Tue	89	—	unknown	22:05–04:40 (good, 6.58 h)	42.9° 01:20	11.31	24%	126.8°
2038-12-01 Wed	89	—	unknown	22:00–04:35 (good, 6.58 h)	42.9° 01:15	11.33	34%	115.6°
2038-12-02 Thu	89	—	unknown	22:05–04:30 (good, 6.42 h)	42.9° 01:10	11.35	44%	104.4°
2038-12-03 Fri	89	—	unknown	22:05–04:25 (good, 6.33 h)	42.9° 01:05	11.37	54%	93.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-11-04&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.