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: 07-16 (2), 07-17 (2), 07-07 (1), 07-08 (1), 07-09 (1) — by astronomy; check the weather when the night is within four days.

2044-06-18astronomy score per night — click a bar for that night2044-07-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-06-18 Sat	0	—	unknown	—	72.5° 11:15	4.42	48%	58.8°
2044-06-19 Sun	0	—	unknown	—	72.6° 11:15	4.42	37%	45.5°
2044-06-20 Mon	0	—	unknown	—	72.6° 11:10	4.42	27%	31.8°
2044-06-21 Tue	0	—	unknown	—	72.6° 11:05	4.42	17%	17.7°
2044-06-22 Wed	0	—	unknown	—	72.6° 11:00	4.43	9%	3.2°
2044-06-23 Thu	0	—	unknown	—	72.5° 11:00	4.43	4%	11.9°
2044-06-24 Fri	0	—	unknown	—	72.6° 10:55	4.44	1%	27.0°
2044-06-25 Sat	0	—	unknown	—	72.6° 10:50	4.45	0%	42.3°
2044-06-26 Sun	0	—	unknown	—	72.6° 10:45	4.46	4%	57.4°
2044-06-27 Mon	0	—	unknown	—	72.6° 10:40	4.48	9%	72.4°
2044-06-28 Tue	0	—	unknown	—	72.6° 10:40	4.49	17%	86.9°
2044-06-29 Wed	0	—	unknown	—	72.6° 10:35	4.51	26%	101.0°
2044-06-30 Thu	0	—	unknown	—	72.6° 10:30	4.53	37%	114.6°
2044-07-01 Fri	0	—	unknown	—	72.6° 10:25	4.55	47%	127.8°
2044-07-02 Sat	0	—	unknown	—	72.5° 10:20	4.58	57%	140.6°
2044-07-03 Sun	0	—	unknown	—	72.6° 10:20	4.6	67%	153.1°
2044-07-04 Mon	0	—	unknown	—	72.6° 10:15	4.63	76%	165.3°
2044-07-05 Tue	0	—	unknown	—	72.6° 10:10	4.66	84%	177.3°
2044-07-06 Wed	0	—	unknown	—	72.6° 10:05	4.69	90%	170.7°
2044-07-07 Thu	1	—	unknown	—	72.5° 10:05	4.72	95%	158.8°
2044-07-08 Fri	1	—	unknown	—	72.6° 10:00	4.75	98%	147.0°
2044-07-09 Sat	1	—	unknown	—	72.6° 09:55	4.79	100%	135.2°
2044-07-10 Sun	1	—	unknown	—	72.6° 09:50	4.82	100%	123.3°
2044-07-11 Mon	1	—	unknown	—	72.6° 09:45	4.86	97%	111.3°
2044-07-12 Tue	1	—	unknown	—	72.6° 09:45	4.9	94%	99.3°
2044-07-13 Wed	1	—	unknown	—	72.6° 09:40	4.94	88%	87.0°
2044-07-14 Thu	1	—	unknown	—	72.6° 09:35	4.98	81%	74.6°
2044-07-15 Fri	1	—	unknown	—	72.6° 09:30	5.03	72%	62.0°
2044-07-16 Sat	2	—	unknown	—	72.6° 09:25	5.07	62%	49.2°
2044-07-17 Sun	2	—	unknown	03:55–04:05 (marginal, 0.17 h)	72.6° 09:25	5.11	52%	36.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-06-18&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.