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.

2043-05-08astronomy score per night — click a bar for that night2043-06-06

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-05-08 Fri	—	unknown	—	42.9° 15:55	5.97	0%	48.2°
2043-05-09 Sat	—	unknown	—	42.9° 15:50	5.91	1%	39.3°
2043-05-10 Sun	—	unknown	—	42.9° 15:45	5.86	5%	34.2°
2043-05-11 Mon	—	unknown	—	42.9° 15:40	5.8	12%	34.6°
2043-05-12 Tue	—	unknown	—	42.9° 15:40	5.75	20%	39.9°
2043-05-13 Wed	—	unknown	—	42.9° 15:35	5.69	30%	48.1°
2043-05-14 Thu	—	unknown	—	42.9° 15:30	5.64	40%	57.8°
2043-05-15 Fri	—	unknown	—	42.9° 15:25	5.58	50%	68.0°
2043-05-16 Sat	—	unknown	—	42.9° 15:20	5.53	61%	78.4°
2043-05-17 Sun	—	unknown	—	42.9° 15:20	5.48	70%	88.7°
2043-05-18 Mon	—	unknown	—	42.9° 15:15	5.43	79%	98.8°
2043-05-19 Tue	—	unknown	—	42.9° 15:10	5.38	86%	108.6°
2043-05-20 Wed	—	unknown	—	42.9° 15:05	5.33	92%	118.1°
2043-05-21 Thu	—	unknown	—	42.9° 15:00	5.28	96%	127.0°
2043-05-22 Fri	—	unknown	—	42.9° 15:00	5.23	99%	135.0°
2043-05-23 Sat	—	unknown	—	42.9° 14:55	5.18	100%	141.5°
2043-05-24 Sun	—	unknown	—	42.9° 14:50	5.13	99%	145.5°
2043-05-25 Mon	—	unknown	—	42.9° 14:45	5.09	96%	146.2°
2043-05-26 Tue	—	unknown	—	42.9° 14:45	5.04	92%	143.2°
2043-05-27 Wed	—	unknown	—	42.9° 14:40	5.0	86%	137.2°
2043-05-28 Thu	—	unknown	—	42.9° 14:35	4.96	78%	129.2°
2043-05-29 Fri	—	unknown	—	42.9° 14:30	4.92	69%	119.9°
2043-05-30 Sat	—	unknown	—	42.9° 14:25	4.88	59%	109.6°
2043-05-31 Sun	—	unknown	—	42.9° 14:25	4.84	49%	98.7°
2043-06-01 Mon	—	unknown	—	42.9° 14:20	4.8	38%	87.3°
2043-06-02 Tue	—	unknown	—	42.9° 14:15	4.76	27%	75.7°
2043-06-03 Wed	—	unknown	—	42.9° 14:10	4.73	17%	64.0°
2043-06-04 Thu	—	unknown	—	42.9° 14:05	4.7	9%	52.8°
2043-06-05 Fri	—	unknown	—	42.9° 14:05	4.67	4%	42.9°
2043-06-06 Sat	—	unknown	—	42.9° 14:00	4.64	1%	35.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-05-08&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.