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: 02-15 (89), 02-16 (86), 02-17 (80), 02-18 (69), 03-03 (60) — by astronomy; check the weather when the night is within four days.

2048-02-15astronomy score per night — click a bar for that night2048-03-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2048-02-15 Sat	89	—	unknown	19:30–23:35 (good, 4.08 h)	42.9° 20:15	10.26	4%	94.4°
2048-02-16 Sun	86	—	unknown	19:30–23:30 (good, 4.0 h)	42.9° 20:15	10.22	10%	83.2°
2048-02-17 Mon	80	—	unknown	19:30–23:30 (good, 4.0 h)	42.9° 20:10	10.18	16%	72.4°
2048-02-18 Tue	69	—	unknown	19:35–23:25 (good, 3.83 h)	42.9° 20:05	10.14	24%	62.0°
2048-02-19 Wed	58	—	unknown	19:35–23:05 (good, 3.5 h)	42.9° 20:00	10.1	33%	52.3°
2048-02-20 Thu	46	—	unknown	19:35–22:50 (good, 3.25 h)	42.9° 19:55	10.05	42%	43.4°
2048-02-21 Fri	34	—	unknown	19:35–23:40 (marginal, 4.08 h)	42.9° 19:55	10.01	51%	36.0°
2048-02-22 Sat	24	—	unknown	19:40–23:25 (marginal, 3.75 h)	42.9° 19:50	9.97	61%	31.0°
2048-02-23 Sun	16	—	unknown	19:40–23:10 (marginal, 3.5 h)	42.9° 19:45	9.93	70%	29.7°
2048-02-24 Mon	13	—	unknown	19:40–22:45 (marginal, 3.08 h)	42.9° 19:40	9.88	78%	32.7°
2048-02-25 Tue	12	—	unknown	19:40–22:30 (marginal, 2.83 h)	42.9° 19:40	9.84	86%	39.1°
2048-02-26 Wed	14	—	unknown	19:40–22:30 (marginal, 2.83 h)	42.9° 19:35	9.8	92%	47.9°
2048-02-27 Thu	18	—	unknown	19:45–22:40 (marginal, 2.92 h)	42.9° 19:30	9.75	97%	58.1°
2048-02-28 Fri	25	—	unknown	19:45–22:50 (marginal, 3.08 h)	42.9° 19:25	9.71	99%	69.2°
2048-02-29 Sat	33	—	unknown	19:45–20:40 (good, 0.92 h)	42.9° 19:20	9.66	100%	80.9°
2048-03-01 Sun	42	—	unknown	19:45–22:05 (good, 2.33 h)	42.9° 19:20	9.62	98%	93.0°
2048-03-02 Mon	57	—	unknown	19:50–22:15 (good, 2.42 h)	42.9° 19:15	9.57	93%	105.2°
2048-03-03 Tue	60	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:10	9.52	86%	117.3°
2048-03-04 Wed	58	—	unknown	19:50–22:25 (good, 2.58 h)	42.9° 19:05	9.48	77%	128.8°
2048-03-05 Thu	57	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:00	9.43	67%	139.1°
2048-03-06 Fri	55	—	unknown	19:55–22:15 (good, 2.33 h)	42.9° 19:00	9.38	56%	147.0°
2048-03-07 Sat	53	—	unknown	19:55–22:15 (good, 2.33 h)	42.9° 18:55	9.34	44%	150.5°
2048-03-08 Sun	51	—	unknown	19:55–22:10 (good, 2.25 h)	42.9° 18:50	9.29	34%	148.1°
2048-03-09 Mon	50	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:45	9.24	23%	141.2°
2048-03-10 Tue	48	—	unknown	20:00–22:00 (good, 2.0 h)	42.9° 18:45	9.19	15%	131.7°
2048-03-11 Wed	46	—	unknown	20:00–22:00 (good, 2.0 h)	42.9° 18:40	9.14	8%	121.0°
2048-03-12 Thu	45	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:35	9.09	3%	109.8°
2048-03-13 Fri	43	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.04	1%	98.4°
2048-03-14 Sat	41	—	unknown	20:00–21:45 (good, 1.75 h)	42.9° 18:25	8.99	0%	87.2°
2048-03-15 Sun	39	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:25	8.94	2%	76.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-02-15&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.