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: 03-03 (60), 03-04 (59), 03-05 (58), 03-02 (57), 03-06 (56) — by astronomy; check the weather when the night is within four days.

2029-02-27astronomy score per night — click a bar for that night2029-03-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-02-27 Tue	23	—	unknown	19:45–22:50 (marginal, 3.08 h)	42.9° 19:25	9.72	99%	67.1°
2029-02-28 Wed	32	—	unknown	19:45–20:30 (good, 0.75 h)	42.9° 19:25	9.68	100%	79.8°
2029-03-01 Thu	42	—	unknown	19:45–22:05 (good, 2.33 h)	42.9° 19:20	9.63	98%	92.9°
2029-03-02 Fri	57	—	unknown	19:50–22:15 (good, 2.42 h)	42.9° 19:15	9.59	92%	105.8°
2029-03-03 Sat	60	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:10	9.54	85%	118.3°
2029-03-04 Sun	59	—	unknown	19:50–22:25 (good, 2.58 h)	42.9° 19:05	9.5	76%	129.9°
2029-03-05 Mon	58	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:05	9.45	65%	139.8°
2029-03-06 Tue	56	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:00	9.4	54%	147.0°
2029-03-07 Wed	54	—	unknown	19:55–22:15 (good, 2.33 h)	42.9° 18:55	9.35	44%	149.8°
2029-03-08 Thu	52	—	unknown	19:55–22:10 (good, 2.25 h)	42.9° 18:50	9.31	33%	147.6°
2029-03-09 Fri	50	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:45	9.26	24%	141.4°
2029-03-10 Sat	49	—	unknown	19:55–22:00 (good, 2.08 h)	42.9° 18:45	9.21	16%	133.1°
2029-03-11 Sun	47	—	unknown	20:00–22:00 (good, 2.0 h)	42.9° 18:40	9.16	10%	123.6°
2029-03-12 Mon	45	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:35	9.11	5%	113.7°
2029-03-13 Tue	43	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.06	2%	103.5°
2029-03-14 Wed	42	—	unknown	20:00–21:45 (good, 1.75 h)	42.9° 18:25	9.01	0%	93.2°
2029-03-15 Thu	40	—	unknown	20:05–21:45 (good, 1.67 h)	42.9° 18:25	8.96	1%	82.9°
2029-03-16 Fri	38	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.91	3%	72.8°
2029-03-17 Sat	35	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:15	8.86	7%	62.8°
2029-03-18 Sun	31	—	unknown	20:05–21:25 (good, 1.33 h)	42.9° 18:10	8.81	12%	53.3°
2029-03-19 Mon	27	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:10	8.76	19%	44.4°
2029-03-20 Tue	22	—	unknown	20:10–21:05 (good, 0.92 h)	42.9° 18:05	8.71	27%	36.8°
2029-03-21 Wed	17	—	unknown	20:10–20:45 (good, 0.58 h)	42.9° 18:00	8.66	36%	31.6°
2029-03-22 Thu	12	—	unknown	20:10–21:40 (marginal, 1.5 h)	42.9° 17:55	8.6	46%	30.1°
2029-03-23 Fri	9	—	unknown	20:15–21:30 (marginal, 1.25 h)	42.9° 17:50	8.55	56%	33.3°
2029-03-24 Sat	7	—	unknown	20:15–21:15 (marginal, 1.0 h)	42.9° 17:50	8.5	67%	40.4°
2029-03-25 Sun	6	—	unknown	21:15–22:05 (marginal, 0.83 h)	42.9° 18:45	8.45	77%	50.1°
2029-03-26 Mon	7	—	unknown	21:15–22:05 (marginal, 0.83 h)	42.9° 18:40	8.39	86%	61.4°
2029-03-27 Tue	7	—	unknown	21:20–22:10 (marginal, 0.83 h)	42.9° 18:35	8.34	93%	73.8°
2029-03-28 Wed	9	—	unknown	21:20–22:15 (marginal, 0.92 h)	42.9° 18:30	8.28	98%	86.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-02-27&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.