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: 03-08 (53), 03-09 (51), 03-10 (50), 03-11 (47), 03-12 (46) — by astronomy; check the weather when the night is within four days.

2043-03-08astronomy score per night — click a bar for that night2043-04-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-03-08 Sun	53	—	unknown	19:55–22:10 (good, 2.25 h)	42.9° 18:55	9.33	8%	119.4°
2043-03-09 Mon	51	—	unknown	19:55–22:10 (good, 2.25 h)	42.9° 18:50	9.28	3%	108.4°
2043-03-10 Tue	50	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:45	9.23	0%	96.6°
2043-03-11 Wed	47	—	unknown	20:00–22:00 (good, 2.0 h)	42.9° 18:40	9.18	0%	84.5°
2043-03-12 Thu	46	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:40	9.13	3%	72.3°
2043-03-13 Fri	42	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:35	9.08	9%	60.5°
2043-03-14 Sat	36	—	unknown	20:00–21:40 (good, 1.67 h)	42.9° 18:30	9.03	17%	49.8°
2043-03-15 Sun	29	—	unknown	20:05–21:30 (good, 1.42 h)	42.9° 18:25	8.98	27%	40.8°
2043-03-16 Mon	22	—	unknown	20:05–21:10 (good, 1.08 h)	42.9° 18:20	8.93	38%	35.1°
2043-03-17 Tue	16	—	unknown	20:05–22:00 (marginal, 1.92 h)	42.9° 18:20	8.88	49%	33.9°
2043-03-18 Wed	12	—	unknown	20:05–21:50 (marginal, 1.75 h)	42.9° 18:15	8.83	60%	37.5°
2043-03-19 Thu	9	—	unknown	20:10–21:35 (marginal, 1.42 h)	42.9° 18:10	8.78	70%	44.5°
2043-03-20 Fri	8	—	unknown	20:10–21:25 (marginal, 1.25 h)	42.9° 18:05	8.73	79%	53.3°
2043-03-21 Sat	9	—	unknown	20:10–21:25 (marginal, 1.25 h)	42.9° 18:00	8.68	87%	63.0°
2043-03-22 Sun	10	—	unknown	20:10–21:30 (marginal, 1.33 h)	42.9° 18:00	8.62	93%	73.2°
2043-03-23 Mon	12	—	unknown	20:15–21:35 (marginal, 1.33 h)	42.9° 17:55	8.57	97%	83.5°
2043-03-24 Tue	14	—	unknown	20:15–20:30 (good, 0.25 h)	42.9° 17:50	8.52	100%	93.8°
2043-03-25 Wed	16	—	unknown	20:15–20:45 (good, 0.5 h)	42.9° 17:45	8.47	100%	103.9°
2043-03-26 Thu	18	—	unknown	20:15–20:50 (good, 0.58 h)	42.9° 17:45	8.41	98%	113.6°
2043-03-27 Fri	20	—	unknown	20:20–20:50 (good, 0.5 h)	42.9° 17:40	8.36	95%	122.9°
2043-03-28 Sat	19	—	unknown	20:20–20:55 (good, 0.58 h)	42.9° 17:35	8.31	90%	131.4°
2043-03-29 Sun	17	—	unknown	21:20–21:50 (good, 0.5 h)	42.9° 18:30	8.25	84%	138.6°
2043-03-30 Mon	15	—	unknown	21:20–21:45 (good, 0.42 h)	42.9° 18:25	8.2	76%	143.9°
2043-03-31 Tue	13	—	unknown	21:25–21:40 (good, 0.25 h)	42.9° 18:25	8.14	68%	146.2°
2043-04-01 Wed	12	—	unknown	21:25–21:40 (good, 0.25 h)	42.9° 18:20	8.09	58%	144.9°
2043-04-02 Thu	10	—	unknown	21:25–21:35 (good, 0.17 h)	42.9° 18:15	8.03	49%	140.1°
2043-04-03 Fri	9	—	unknown	21:25–21:30 (good, 0.08 h)	42.9° 18:10	7.98	38%	132.8°
2043-04-04 Sat	7	—	unknown	21:30–21:55 (marginal, 0.42 h)	42.9° 18:05	7.92	29%	123.6°
2043-04-05 Sun	6	—	unknown	21:30–21:55 (marginal, 0.42 h)	42.9° 18:05	7.87	19%	113.2°
2043-04-06 Mon	5	—	unknown	21:30–21:50 (marginal, 0.33 h)	42.9° 18:00	7.81	11%	101.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-03-08&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.