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.

2045-03-26astronomy score per night — click a bar for that night2045-04-24

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-03-26 Sun	—	unknown	—	89.8° 13:50	8.39	60%	80.2°
2045-03-27 Mon	—	unknown	—	89.8° 13:45	8.33	71%	92.7°
2045-03-28 Tue	—	unknown	—	89.7° 13:40	8.28	81%	105.2°
2045-03-29 Wed	—	unknown	—	89.5° 13:35	8.22	89%	117.6°
2045-03-30 Thu	—	unknown	—	89.6° 13:35	8.17	95%	129.4°
2045-03-31 Fri	—	unknown	—	89.8° 13:30	8.12	99%	139.9°
2045-04-01 Sat	—	unknown	—	89.8° 13:25	8.06	100%	147.8°
2045-04-02 Sun	—	unknown	—	89.7° 13:20	8.01	98%	151.0°
2045-04-03 Mon	—	unknown	—	89.5° 13:20	7.95	94%	148.6°
2045-04-04 Tue	—	unknown	—	89.7° 13:15	7.89	88%	141.8°
2045-04-05 Wed	—	unknown	—	89.8° 13:10	7.84	81%	133.0°
2045-04-06 Thu	—	unknown	—	89.8° 13:05	7.78	72%	123.1°
2045-04-07 Fri	—	unknown	—	89.6° 13:00	7.73	63%	112.9°
2045-04-08 Sat	—	unknown	—	89.6° 13:00	7.67	54%	102.6°
2045-04-09 Sun	—	unknown	—	89.8° 12:55	7.61	44%	92.3°
2045-04-10 Mon	—	unknown	—	89.8° 12:50	7.56	35%	81.9°
2045-04-11 Tue	—	unknown	—	89.7° 12:45	7.5	26%	71.6°
2045-04-12 Wed	—	unknown	—	89.5° 12:40	7.44	18%	61.4°
2045-04-13 Thu	—	unknown	—	89.6° 12:40	7.39	12%	51.6°
2045-04-14 Fri	—	unknown	—	89.8° 12:35	7.33	6%	42.3°
2045-04-15 Sat	—	unknown	—	89.8° 12:30	7.27	2%	34.5°
2045-04-16 Sun	—	unknown	—	89.7° 12:25	7.21	0%	29.7°
2045-04-17 Mon	—	unknown	—	89.5° 12:25	7.15	1%	29.7°
2045-04-18 Tue	—	unknown	—	89.7° 12:20	7.1	3%	34.8°
2045-04-19 Wed	—	unknown	—	89.8° 12:15	7.04	8%	43.3°
2045-04-20 Thu	—	unknown	—	89.8° 12:10	6.98	15%	53.8°
2045-04-21 Fri	—	unknown	—	89.6° 12:05	6.92	24%	65.4°
2045-04-22 Sat	—	unknown	—	89.7° 12:00	6.86	35%	77.5°
2045-04-23 Sun	—	unknown	—	89.8° 11:55	6.81	46%	89.8°
2045-04-24 Mon	—	unknown	—	89.7° 11:50	6.75	57%	102.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-03-26&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.