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: 02-24 (73), 02-23 (72), 02-25 (72), 02-26 (69), 02-27 (69) — by astronomy; check the weather when the night is within four days.

2046-02-19astronomy score per night — click a bar for that night2046-03-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-02-19 Mon	21	—	unknown	19:35–23:05 (marginal, 3.5 h)	42.9° 20:00	10.08	98%	58.5°
2046-02-20 Tue	31	—	unknown	19:35–23:20 (marginal, 3.75 h)	42.9° 19:55	10.03	100%	70.7°
2046-02-21 Wed	43	—	unknown	19:35–21:30 (good, 1.92 h)	42.9° 19:50	9.99	98%	83.4°
2046-02-22 Thu	66	—	unknown	19:40–22:40 (good, 3.0 h)	42.9° 19:45	9.95	94%	96.1°
2046-02-23 Fri	72	—	unknown	19:40–22:50 (good, 3.17 h)	42.9° 19:45	9.91	87%	108.5°
2046-02-24 Sat	73	—	unknown	19:40–22:55 (good, 3.25 h)	42.9° 19:40	9.86	78%	120.2°
2046-02-25 Sun	72	—	unknown	19:40–22:55 (good, 3.25 h)	42.9° 19:35	9.82	68%	130.7°
2046-02-26 Mon	69	—	unknown	19:45–22:50 (good, 3.08 h)	42.9° 19:30	9.77	58%	139.3°
2046-02-27 Tue	69	—	unknown	19:45–22:45 (good, 3.0 h)	42.9° 19:30	9.73	47%	145.3°
2046-02-28 Wed	67	—	unknown	19:45–22:45 (good, 3.0 h)	42.9° 19:25	9.69	37%	147.3°
2046-03-01 Thu	65	—	unknown	19:45–22:40 (good, 2.92 h)	42.9° 19:20	9.64	28%	145.2°
2046-03-02 Fri	63	—	unknown	19:45–22:35 (good, 2.83 h)	42.9° 19:15	9.59	20%	139.7°
2046-03-03 Sat	61	—	unknown	19:50–22:30 (good, 2.67 h)	42.9° 19:10	9.55	12%	132.2°
2046-03-04 Sun	60	—	unknown	19:50–22:25 (good, 2.58 h)	42.9° 19:10	9.5	7%	123.5°
2046-03-05 Mon	58	—	unknown	19:50–22:25 (good, 2.58 h)	42.9° 19:05	9.45	3%	114.2°
2046-03-06 Tue	56	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:00	9.41	1%	104.5°
2046-03-07 Wed	54	—	unknown	19:55–22:15 (good, 2.33 h)	42.9° 18:55	9.36	0%	94.6°
2046-03-08 Thu	53	—	unknown	19:55–22:10 (good, 2.25 h)	42.9° 18:50	9.31	1%	84.6°
2046-03-09 Fri	50	—	unknown	19:55–22:10 (good, 2.25 h)	42.9° 18:50	9.26	4%	74.7°
2046-03-10 Sat	47	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:45	9.22	9%	64.9°
2046-03-11 Sun	41	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:40	9.17	15%	55.4°
2046-03-12 Mon	35	—	unknown	20:00–21:45 (good, 1.75 h)	42.9° 18:35	9.12	23%	46.6°
2046-03-13 Tue	29	—	unknown	20:00–21:30 (good, 1.5 h)	42.9° 18:35	9.07	32%	39.1°
2046-03-14 Wed	22	—	unknown	20:00–20:20 (good, 0.33 h)	42.9° 18:30	9.02	42%	33.9°
2046-03-15 Thu	15	—	unknown	20:05–22:05 (marginal, 2.0 h)	42.9° 18:25	8.97	52%	32.7°
2046-03-16 Fri	11	—	unknown	20:05–21:50 (marginal, 1.75 h)	42.9° 18:20	8.92	63%	36.1°
2046-03-17 Sat	9	—	unknown	20:05–21:35 (marginal, 1.5 h)	42.9° 18:15	8.87	74%	43.4°
2046-03-18 Sun	9	—	unknown	20:05–21:30 (marginal, 1.42 h)	42.9° 18:15	8.82	83%	53.4°
2046-03-19 Mon	10	—	unknown	20:10–21:35 (marginal, 1.42 h)	42.9° 18:10	8.77	91%	64.9°
2046-03-20 Tue	13	—	unknown	20:10–21:40 (marginal, 1.5 h)	42.9° 18:05	8.71	97%	77.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-02-19&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.