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: 01-06 (89), 01-07 (89), 01-08 (89), 01-09 (89), 01-10 (89) — by astronomy; check the weather when the night is within four days.

2048-01-05astronomy score per night — click a bar for that night2048-02-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2048-01-05 Sun	86	—	unknown	19:45–00:55 (good, 5.17 h)	42.9° 23:00	11.41	79%	75.9°
2048-01-06 Mon	89	—	unknown	19:40–01:50 (good, 6.17 h)	42.9° 22:55	11.39	70%	87.4°
2048-01-07 Tue	89	—	unknown	19:35–01:55 (good, 6.33 h)	42.9° 22:50	11.38	59%	99.1°
2048-01-08 Wed	89	—	unknown	19:30–02:00 (good, 6.5 h)	42.9° 22:45	11.36	48%	110.9°
2048-01-09 Thu	89	—	unknown	19:30–02:00 (good, 6.5 h)	42.9° 22:40	11.35	37%	122.6°
2048-01-10 Fri	89	—	unknown	19:25–02:00 (good, 6.58 h)	42.9° 22:40	11.33	26%	133.7°
2048-01-11 Sat	89	—	unknown	19:20–01:55 (good, 6.58 h)	42.9° 22:35	11.31	17%	143.2°
2048-01-12 Sun	89	—	unknown	19:15–01:50 (good, 6.58 h)	42.9° 22:30	11.29	9%	149.2°
2048-01-13 Mon	89	—	unknown	19:10–01:45 (good, 6.58 h)	42.9° 22:25	11.27	3%	149.6°
2048-01-14 Tue	89	—	unknown	19:10–01:40 (good, 6.5 h)	42.9° 22:25	11.25	0%	144.0°
2048-01-15 Wed	89	—	unknown	19:05–01:40 (good, 6.58 h)	42.9° 22:20	11.23	0%	134.8°
2048-01-16 Thu	89	—	unknown	19:00–01:35 (good, 6.58 h)	42.9° 22:15	11.21	3%	124.0°
2048-01-17 Fri	89	—	unknown	19:00–01:30 (good, 6.5 h)	42.9° 22:10	11.19	8%	112.6°
2048-01-18 Sat	89	—	unknown	19:00–01:25 (good, 6.42 h)	42.9° 22:05	11.16	14%	101.2°
2048-01-19 Sun	89	—	unknown	19:00–01:20 (good, 6.33 h)	42.9° 22:05	11.14	22%	90.0°
2048-01-20 Mon	87	—	unknown	19:00–01:20 (good, 6.33 h)	42.9° 22:00	11.12	31%	79.1°
2048-01-21 Tue	83	—	unknown	19:05–01:15 (good, 6.17 h)	42.9° 21:55	11.09	41%	68.6°
2048-01-22 Wed	69	—	unknown	19:40–00:50 (good, 5.17 h)	42.9° 21:50	11.06	50%	58.6°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-01-05&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.