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: 02-21 (78), 02-22 (76), 02-23 (74), 02-24 (73), 02-25 (72) — by astronomy; check the weather when the night is within four days.

2033-02-21astronomy score per night — click a bar for that night2033-03-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-02-21 Mon	78	—	unknown	19:35–23:10 (good, 3.58 h)	42.9° 19:50	9.99	56%	144.4°
2033-02-22 Tue	76	—	unknown	19:40–23:05 (good, 3.42 h)	42.9° 19:45	9.94	46%	152.1°
2033-02-23 Wed	74	—	unknown	19:40–23:00 (good, 3.33 h)	42.9° 19:40	9.9	35%	155.8°
2033-02-24 Thu	73	—	unknown	19:40–22:55 (good, 3.25 h)	42.9° 19:40	9.86	25%	153.1°
2033-02-25 Fri	72	—	unknown	19:40–22:55 (good, 3.25 h)	42.9° 19:35	9.81	16%	145.0°
2033-02-26 Sat	69	—	unknown	19:45–22:50 (good, 3.08 h)	42.9° 19:30	9.77	9%	133.9°
2033-02-27 Sun	68	—	unknown	19:45–22:45 (good, 3.0 h)	42.9° 19:25	9.72	3%	121.2°
2033-02-28 Mon	66	—	unknown	19:45–22:40 (good, 2.92 h)	42.9° 19:25	9.68	0%	107.7°
2033-03-01 Tue	65	—	unknown	19:45–22:40 (good, 2.92 h)	42.9° 19:20	9.63	1%	93.9°
2033-03-02 Wed	62	—	unknown	19:50–22:35 (good, 2.75 h)	42.9° 19:15	9.59	4%	80.0°
2033-03-03 Thu	58	—	unknown	19:50–22:30 (good, 2.67 h)	42.9° 19:10	9.54	10%	66.4°
2033-03-04 Fri	50	—	unknown	19:50–22:25 (good, 2.58 h)	42.9° 19:05	9.49	18%	53.5°
2033-03-05 Sat	42	—	unknown	19:50–22:10 (good, 2.33 h)	42.9° 19:05	9.45	28%	41.7°
2033-03-06 Sun	32	—	unknown	19:50–21:50 (good, 2.0 h)	42.9° 19:00	9.4	38%	31.7°
2033-03-07 Mon	23	—	unknown	19:55–22:40 (marginal, 2.75 h)	42.9° 18:55	9.35	49%	25.3°
2033-03-08 Tue	16	—	unknown	19:55–22:25 (marginal, 2.5 h)	42.9° 18:50	9.31	59%	24.6°
2033-03-09 Wed	11	—	unknown	19:55–22:05 (marginal, 2.17 h)	42.9° 18:45	9.26	69%	29.6°
2033-03-10 Thu	10	—	unknown	19:55–21:55 (marginal, 2.0 h)	42.9° 18:45	9.21	78%	37.8°
2033-03-11 Fri	10	—	unknown	20:00–21:50 (marginal, 1.83 h)	42.9° 18:40	9.16	85%	47.5°
2033-03-12 Sat	12	—	unknown	20:00–21:55 (marginal, 1.92 h)	42.9° 18:35	9.11	91%	57.8°
2033-03-13 Sun	14	—	unknown	20:00–22:00 (marginal, 2.0 h)	42.9° 18:30	9.06	96%	68.4°
2033-03-14 Mon	18	—	unknown	20:00–22:05 (marginal, 2.08 h)	42.9° 18:30	9.01	99%	79.2°
2033-03-15 Tue	22	—	unknown	20:05–20:45 (good, 0.67 h)	42.9° 18:25	8.96	100%	89.9°
2033-03-16 Wed	26	—	unknown	20:05–21:15 (good, 1.17 h)	42.9° 18:20	8.91	99%	100.8°
2033-03-17 Thu	29	—	unknown	20:05–21:20 (good, 1.25 h)	42.9° 18:15	8.86	97%	111.5°
2033-03-18 Fri	34	—	unknown	20:05–21:25 (good, 1.33 h)	42.9° 18:10	8.81	93%	122.1°
2033-03-19 Sat	33	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:10	8.76	87%	132.4°
2033-03-20 Sun	31	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:05	8.71	80%	142.1°
2033-03-21 Mon	30	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:00	8.65	71%	150.4°
2033-03-22 Tue	28	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 17:55	8.6	62%	155.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-02-21&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.