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 Seven Sisters: 07-14 (3), 07-15 (3), 07-12 (2), 07-13 (2), 07-09 (1) — by astronomy; check the weather when the night is within four days.

2045-06-16astronomy score per night — click a bar for that night2045-07-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-06-16 Fri	0	—	unknown	—	72.6° 11:25	4.44	5%	51.2°
2045-06-17 Sat	0	—	unknown	—	72.6° 11:20	4.43	11%	66.1°
2045-06-18 Sun	0	—	unknown	—	72.6° 11:20	4.43	20%	80.8°
2045-06-19 Mon	0	—	unknown	—	72.6° 11:15	4.42	30%	95.3°
2045-06-20 Tue	0	—	unknown	—	72.6° 11:10	4.42	41%	109.5°
2045-06-21 Wed	0	—	unknown	—	72.6° 11:05	4.42	52%	123.4°
2045-06-22 Thu	0	—	unknown	—	72.6° 11:05	4.43	63%	137.0°
2045-06-23 Fri	0	—	unknown	—	72.6° 11:00	4.43	73%	150.3°
2045-06-24 Sat	0	—	unknown	—	72.6° 10:55	4.44	82%	163.4°
2045-06-25 Sun	0	—	unknown	—	72.6° 10:50	4.45	89%	176.2°
2045-06-26 Mon	0	—	unknown	—	72.6° 10:45	4.46	94%	171.0°
2045-06-27 Tue	0	—	unknown	—	72.6° 10:45	4.47	98%	158.6°
2045-06-28 Wed	0	—	unknown	—	72.6° 10:40	4.49	100%	146.3°
2045-06-29 Thu	0	—	unknown	—	72.6° 10:35	4.51	100%	134.2°
2045-06-30 Fri	0	—	unknown	—	72.6° 10:30	4.53	98%	122.2°
2045-07-01 Sat	0	—	unknown	—	72.6° 10:25	4.55	94%	110.3°
2045-07-02 Sun	0	—	unknown	—	72.6° 10:25	4.57	88%	98.5°
2045-07-03 Mon	0	—	unknown	—	72.6° 10:20	4.59	82%	86.7°
2045-07-04 Tue	0	—	unknown	—	72.6° 10:15	4.62	74%	74.8°
2045-07-05 Wed	0	—	unknown	—	72.6° 10:10	4.65	65%	62.8°
2045-07-06 Thu	0	—	unknown	—	72.6° 10:10	4.68	55%	50.6°
2045-07-07 Fri	0	—	unknown	—	72.6° 10:05	4.71	45%	38.2°
2045-07-08 Sat	0	—	unknown	—	72.6° 10:00	4.74	35%	25.4°
2045-07-09 Sun	1	—	unknown	—	72.6° 09:55	4.78	26%	12.2°
2045-07-10 Mon	1	—	unknown	—	72.6° 09:50	4.81	17%	1.8°
2045-07-11 Tue	1	—	unknown	—	72.6° 09:50	4.85	9%	15.6°
2045-07-12 Wed	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.6° 09:45	4.89	3%	30.1°
2045-07-13 Thu	2	—	unknown	04:35–04:45 (marginal, 0.17 h)	72.6° 09:40	4.93	0%	45.0°
2045-07-14 Fri	3	—	unknown	04:30–04:50 (marginal, 0.33 h)	72.6° 09:35	4.97	0%	60.1°
2045-07-15 Sat	3	—	unknown	04:25–04:50 (marginal, 0.42 h)	72.6° 09:30	5.02	3%	75.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-06-16&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.