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: 02-03 (89), 02-04 (89), 02-05 (89), 02-06 (89), 02-07 (89) — by astronomy; check the weather when the night is within four days.

2046-02-03astronomy score per night — click a bar for that night2046-03-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-02-03 Sat	89	—	unknown	19:15–00:20 (good, 5.08 h)	42.9° 21:00	10.69	4%	138.0°
2046-02-04 Sun	89	—	unknown	19:20–00:15 (good, 4.92 h)	42.9° 21:00	10.65	1%	130.1°
2046-02-05 Mon	89	—	unknown	19:20–00:15 (good, 4.92 h)	42.9° 20:55	10.62	0%	121.2°
2046-02-06 Tue	89	—	unknown	19:20–00:10 (good, 4.83 h)	42.9° 20:50	10.58	1%	111.7°
2046-02-07 Wed	89	—	unknown	19:20–00:05 (good, 4.75 h)	42.9° 20:45	10.54	4%	102.0°
2046-02-08 Thu	89	—	unknown	19:20–00:00 (good, 4.67 h)	42.9° 20:40	10.51	8%	92.0°
2046-02-09 Fri	88	—	unknown	19:25–00:00 (good, 4.58 h)	42.9° 20:40	10.47	14%	82.1°
2046-02-10 Sat	85	—	unknown	19:25–23:55 (good, 4.5 h)	42.9° 20:35	10.43	21%	72.2°
2046-02-11 Sun	75	—	unknown	19:25–23:50 (good, 4.42 h)	42.9° 20:30	10.4	29%	62.5°
2046-02-12 Mon	61	—	unknown	19:25–23:30 (good, 4.08 h)	42.9° 20:25	10.36	38%	53.1°
2046-02-13 Tue	47	—	unknown	19:30–23:10 (good, 3.67 h)	42.9° 20:25	10.32	48%	44.5°
2046-02-14 Wed	33	—	unknown	19:30–00:05 (marginal, 4.58 h)	42.9° 20:20	10.28	58%	37.4°
2046-02-15 Thu	22	—	unknown	19:30–23:45 (marginal, 4.25 h)	42.9° 20:15	10.24	68%	33.2°
2046-02-16 Fri	15	—	unknown	19:30–23:20 (marginal, 3.83 h)	42.9° 20:10	10.2	78%	33.5°
2046-02-17 Sat	13	—	unknown	19:30–22:55 (marginal, 3.42 h)	42.9° 20:05	10.16	87%	38.7°
2046-02-18 Sun	15	—	unknown	19:35–22:55 (marginal, 3.33 h)	42.9° 20:05	10.12	94%	47.5°
2046-02-19 Mon	21	—	unknown	19:35–23:05 (marginal, 3.5 h)	42.9° 20:00	10.08	98%	58.5°
2046-02-20 Tue	31	—	unknown	19:35–23:20 (marginal, 3.75 h)	42.9° 19:55	10.03	100%	70.7°
2046-02-21 Wed	43	—	unknown	19:35–21:30 (good, 1.92 h)	42.9° 19:50	9.99	98%	83.4°
2046-02-22 Thu	66	—	unknown	19:40–22:40 (good, 3.0 h)	42.9° 19:45	9.95	94%	96.1°
2046-02-23 Fri	72	—	unknown	19:40–22:50 (good, 3.17 h)	42.9° 19:45	9.91	87%	108.5°
2046-02-24 Sat	73	—	unknown	19:40–22:55 (good, 3.25 h)	42.9° 19:40	9.86	78%	120.2°
2046-02-25 Sun	72	—	unknown	19:40–22:55 (good, 3.25 h)	42.9° 19:35	9.82	68%	130.7°
2046-02-26 Mon	69	—	unknown	19:45–22:50 (good, 3.08 h)	42.9° 19:30	9.77	58%	139.3°
2046-02-27 Tue	69	—	unknown	19:45–22:45 (good, 3.0 h)	42.9° 19:30	9.73	47%	145.3°
2046-02-28 Wed	67	—	unknown	19:45–22:45 (good, 3.0 h)	42.9° 19:25	9.69	37%	147.3°
2046-03-01 Thu	65	—	unknown	19:45–22:40 (good, 2.92 h)	42.9° 19:20	9.64	28%	145.2°
2046-03-02 Fri	63	—	unknown	19:45–22:35 (good, 2.83 h)	42.9° 19:15	9.59	20%	139.7°
2046-03-03 Sat	61	—	unknown	19:50–22:30 (good, 2.67 h)	42.9° 19:10	9.55	12%	132.2°
2046-03-04 Sun	60	—	unknown	19:50–22:25 (good, 2.58 h)	42.9° 19:10	9.5	7%	123.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-02-03&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.