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: 02-23 (76), 02-24 (74), 02-25 (73), 02-26 (71), 02-27 (69) — by astronomy; check the weather when the night is within four days.

2036-02-23astronomy score per night — click a bar for that night2036-03-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-02-23 Sat	76	—	unknown	19:40–23:05 (good, 3.42 h)	42.9° 19:45	9.93	10%	136.8°
2036-02-24 Sun	74	—	unknown	19:40–23:00 (good, 3.33 h)	42.9° 19:40	9.89	5%	126.9°
2036-02-25 Mon	73	—	unknown	19:40–22:55 (good, 3.25 h)	42.9° 19:35	9.84	2%	116.3°
2036-02-26 Tue	71	—	unknown	19:40–22:55 (good, 3.25 h)	42.9° 19:35	9.8	0%	105.4°
2036-02-27 Wed	69	—	unknown	19:45–22:50 (good, 3.08 h)	42.9° 19:30	9.76	0%	94.2°
2036-02-28 Thu	67	—	unknown	19:45–22:45 (good, 3.0 h)	42.9° 19:25	9.71	3%	82.8°
2036-02-29 Fri	64	—	unknown	19:45–22:40 (good, 2.92 h)	42.9° 19:20	9.67	7%	71.3°
2036-03-01 Sat	59	—	unknown	19:45–22:35 (good, 2.83 h)	42.9° 19:20	9.62	14%	59.8°
2036-03-02 Sun	51	—	unknown	19:50–22:25 (good, 2.58 h)	42.9° 19:15	9.57	22%	48.5°
2036-03-03 Mon	41	—	unknown	19:50–22:10 (good, 2.33 h)	42.9° 19:10	9.53	31%	37.9°
2036-03-04 Tue	30	—	unknown	19:50–21:50 (good, 2.0 h)	42.9° 19:05	9.48	42%	28.9°
2036-03-05 Wed	22	—	unknown	19:50–22:45 (marginal, 2.92 h)	42.9° 19:00	9.44	53%	24.1°
2036-03-06 Thu	15	—	unknown	19:55–22:30 (marginal, 2.58 h)	42.9° 19:00	9.39	64%	26.3°
2036-03-07 Fri	11	—	unknown	19:55–22:05 (marginal, 2.17 h)	42.9° 18:55	9.34	75%	34.4°
2036-03-08 Sat	11	—	unknown	19:55–22:00 (marginal, 2.08 h)	42.9° 18:50	9.29	84%	45.7°
2036-03-09 Sun	13	—	unknown	19:55–22:00 (marginal, 2.08 h)	42.9° 18:45	9.24	92%	58.2°
2036-03-10 Mon	17	—	unknown	19:55–22:10 (marginal, 2.25 h)	42.9° 18:40	9.2	97%	71.4°
2036-03-11 Tue	22	—	unknown	20:00–20:10 (good, 0.17 h)	42.9° 18:40	9.15	100%	84.7°
2036-03-12 Wed	28	—	unknown	20:00–21:25 (good, 1.42 h)	42.9° 18:35	9.1	100%	97.9°
2036-03-13 Thu	34	—	unknown	20:00–21:35 (good, 1.58 h)	42.9° 18:30	9.05	97%	110.7°
2036-03-14 Fri	40	—	unknown	20:00–21:35 (good, 1.58 h)	42.9° 18:25	9.0	92%	123.0°
2036-03-15 Sat	39	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:25	8.95	85%	134.3°
2036-03-16 Sun	38	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.9	77%	144.4°
2036-03-17 Mon	36	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:15	8.85	68%	152.1°
2036-03-18 Tue	34	—	unknown	20:05–21:30 (good, 1.42 h)	42.9° 18:10	8.8	58%	155.9°
2036-03-19 Wed	32	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:05	8.74	48%	154.2°
2036-03-20 Thu	31	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:05	8.69	39%	148.1°
2036-03-21 Fri	29	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:00	8.64	30%	139.7°
2036-03-22 Sat	28	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 17:55	8.59	22%	130.0°
2036-03-23 Sun	26	—	unknown	20:15–21:10 (good, 0.92 h)	42.9° 17:50	8.54	14%	119.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-02-23&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.