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: 02-28 (66), 03-01 (65), 03-02 (63), 03-03 (61), 03-04 (60) — by astronomy; check the weather when the night is within four days.

2038-02-28astronomy score per night — click a bar for that night2038-03-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-02-28 Sun	66	—	unknown	19:45–22:45 (good, 3.0 h)	42.9° 19:25	9.69	23%	146.0°
2038-03-01 Mon	65	—	unknown	19:45–22:40 (good, 2.92 h)	42.9° 19:20	9.64	15%	137.1°
2038-03-02 Tue	63	—	unknown	19:45–22:35 (good, 2.83 h)	42.9° 19:15	9.6	9%	127.0°
2038-03-03 Wed	61	—	unknown	19:50–22:30 (good, 2.67 h)	42.9° 19:10	9.55	4%	116.4°
2038-03-04 Thu	60	—	unknown	19:50–22:25 (good, 2.58 h)	42.9° 19:10	9.5	1%	105.6°
2038-03-05 Fri	58	—	unknown	19:50–22:25 (good, 2.58 h)	42.9° 19:05	9.46	0%	94.8°
2038-03-06 Sat	56	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:00	9.41	1%	84.1°
2038-03-07 Sun	54	—	unknown	19:55–22:15 (good, 2.33 h)	42.9° 18:55	9.36	4%	73.5°
2038-03-08 Mon	50	—	unknown	19:55–22:10 (good, 2.25 h)	42.9° 18:50	9.32	8%	63.1°
2038-03-09 Tue	46	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:50	9.27	14%	53.1°
2038-03-10 Wed	40	—	unknown	19:55–21:55 (good, 2.0 h)	42.9° 18:45	9.22	21%	43.6°
2038-03-11 Thu	32	—	unknown	20:00–21:40 (good, 1.67 h)	42.9° 18:40	9.17	29%	35.2°
2038-03-12 Fri	25	—	unknown	20:00–21:25 (good, 1.42 h)	42.9° 18:35	9.12	38%	28.9°
2038-03-13 Sat	19	—	unknown	20:00–22:20 (marginal, 2.33 h)	42.9° 18:35	9.07	48%	26.5°
2038-03-14 Sun	14	—	unknown	20:00–22:05 (marginal, 2.08 h)	42.9° 18:30	9.02	58%	29.3°
2038-03-15 Mon	10	—	unknown	20:05–21:50 (marginal, 1.75 h)	42.9° 18:25	8.97	68%	36.4°
2038-03-16 Tue	9	—	unknown	20:05–21:40 (marginal, 1.58 h)	42.9° 18:20	8.92	78%	46.2°
2038-03-17 Wed	10	—	unknown	20:05–21:35 (marginal, 1.5 h)	42.9° 18:15	8.87	86%	57.7°
2038-03-18 Thu	12	—	unknown	20:05–21:40 (marginal, 1.58 h)	42.9° 18:15	8.82	93%	70.2°
2038-03-19 Fri	15	—	unknown	20:10–21:50 (marginal, 1.67 h)	42.9° 18:10	8.77	98%	83.4°
2038-03-20 Sat	19	—	unknown	20:10–20:50 (good, 0.67 h)	42.9° 18:05	8.72	100%	96.9°
2038-03-21 Sun	22	—	unknown	20:10–21:05 (good, 0.92 h)	42.9° 18:00	8.67	99%	110.4°
2038-03-22 Mon	27	—	unknown	20:10–21:05 (good, 0.92 h)	42.9° 17:55	8.61	95%	123.5°
2038-03-23 Tue	27	—	unknown	20:15–21:10 (good, 0.92 h)	42.9° 17:55	8.56	88%	135.6°
2038-03-24 Wed	25	—	unknown	20:15–21:10 (good, 0.92 h)	42.9° 17:50	8.51	79%	145.9°
2038-03-25 Thu	24	—	unknown	20:15–21:05 (good, 0.83 h)	42.9° 17:45	8.46	69%	152.3°
2038-03-26 Fri	22	—	unknown	20:15–21:00 (good, 0.75 h)	42.9° 17:40	8.4	59%	152.8°
2038-03-27 Sat	20	—	unknown	20:20–20:55 (good, 0.58 h)	42.9° 17:40	8.35	48%	147.6°
2038-03-28 Sun	19	—	unknown	21:20–21:55 (good, 0.58 h)	42.9° 18:35	8.3	38%	139.2°
2038-03-29 Mon	17	—	unknown	21:20–21:50 (good, 0.5 h)	42.9° 18:30	8.24	28%	129.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-02-28&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.