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.

2048-01-23astronomy score per night — click a bar for that night2048-02-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2048-01-23 Thu	57	—	unknown	22:40–00:20 (good, 1.67 h)	42.9° 21:45	11.04	60%	49.2°
2048-01-24 Fri	40	—	unknown	19:05–01:25 (marginal, 6.33 h)	42.9° 21:45	11.01	69%	40.9°
2048-01-25 Sat	26	—	unknown	19:05–01:10 (marginal, 6.08 h)	42.9° 21:40	10.98	77%	34.1°
2048-01-26 Sun	16	—	unknown	20:55–00:35 (marginal, 3.67 h)	42.9° 21:35	10.95	84%	30.2°
2048-01-27 Mon	12	—	unknown	—	42.9° 21:30	10.92	91%	30.4°
2048-01-28 Tue	14	—	unknown	19:10–20:05 (marginal, 0.92 h)	42.9° 21:30	10.89	96%	34.7°
2048-01-29 Wed	19	—	unknown	19:10–22:10 (marginal, 3.0 h)	42.9° 21:25	10.86	99%	42.2°
2048-01-30 Thu	28	—	unknown	19:10–00:10 (marginal, 5.0 h)	42.9° 21:20	10.83	100%	51.5°
2048-01-31 Fri	40	—	unknown	19:15–00:30 (marginal, 5.25 h)	42.9° 21:15	10.8	99%	61.9°
2048-02-01 Sat	74	—	unknown	19:15–21:35 (good, 2.33 h)	42.9° 21:10	10.77	96%	73.1°
2048-02-02 Sun	88	—	unknown	19:15–23:25 (good, 4.17 h)	42.9° 21:10	10.74	90%	84.7°
2048-02-03 Mon	89	—	unknown	19:15–00:00 (good, 4.75 h)	42.9° 21:05	10.7	83%	96.6°
2048-02-04 Tue	89	—	unknown	19:15–00:10 (good, 4.92 h)	42.9° 21:00	10.67	74%	108.4°
2048-02-05 Wed	89	—	unknown	19:20–00:15 (good, 4.92 h)	42.9° 20:55	10.63	63%	120.1°
2048-02-06 Thu	89	—	unknown	19:20–00:10 (good, 4.83 h)	42.9° 20:50	10.6	52%	131.2°
2048-02-07 Fri	89	—	unknown	19:20–00:10 (good, 4.83 h)	42.9° 20:50	10.56	41%	141.0°
2048-02-08 Sat	89	—	unknown	19:20–00:05 (good, 4.75 h)	42.9° 20:45	10.53	30%	148.0°
2048-02-09 Sun	89	—	unknown	19:25–00:00 (good, 4.58 h)	42.9° 20:40	10.49	20%	150.2°
2048-02-10 Mon	89	—	unknown	19:25–23:55 (good, 4.5 h)	42.9° 20:35	10.45	12%	146.6°
2048-02-11 Tue	89	—	unknown	19:25–23:50 (good, 4.42 h)	42.9° 20:35	10.41	5%	138.6°
2048-02-12 Wed	89	—	unknown	19:25–23:50 (good, 4.42 h)	42.9° 20:30	10.38	2%	128.4°
2048-02-13 Thu	89	—	unknown	19:25–23:45 (good, 4.33 h)	42.9° 20:25	10.34	0%	117.3°
2048-02-14 Fri	89	—	unknown	19:30–23:40 (good, 4.17 h)	42.9° 20:20	10.3	1%	105.8°
2048-02-15 Sat	89	—	unknown	19:30–23:35 (good, 4.08 h)	42.9° 20:15	10.26	4%	94.4°
2048-02-16 Sun	86	—	unknown	19:30–23:30 (good, 4.0 h)	42.9° 20:15	10.22	10%	83.2°
2048-02-17 Mon	80	—	unknown	19:30–23:30 (good, 4.0 h)	42.9° 20:10	10.18	16%	72.4°
2048-02-18 Tue	69	—	unknown	19:35–23:25 (good, 3.83 h)	42.9° 20:05	10.14	24%	62.0°
2048-02-19 Wed	58	—	unknown	19:35–23:05 (good, 3.5 h)	42.9° 20:00	10.1	33%	52.3°
2048-02-20 Thu	46	—	unknown	19:35–22:50 (good, 3.25 h)	42.9° 19:55	10.05	42%	43.4°
2048-02-21 Fri	34	—	unknown	19:35–23:40 (marginal, 4.08 h)	42.9° 19:55	10.01	51%	36.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-01-23&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.