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: 04-10 (1), 04-11 (1), 04-12 (1) — by astronomy; check the weather when the night is within four days.

2027-04-10astronomy score per night — click a bar for that night2027-05-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-04-10 Sat	1	—	unknown	—	72.5° 15:55	7.59	18%	11.3°
2027-04-11 Sun	1	—	unknown	—	72.5° 15:50	7.54	28%	25.4°
2027-04-12 Mon	1	—	unknown	—	72.5° 15:45	7.48	38%	39.5°
2027-04-13 Tue	0	—	unknown	—	72.5° 15:45	7.42	50%	53.6°
2027-04-14 Wed	0	—	unknown	—	72.5° 15:40	7.36	61%	67.8°
2027-04-15 Thu	0	—	unknown	—	72.5° 15:35	7.31	72%	81.9°
2027-04-16 Fri	0	—	unknown	—	72.5° 15:30	7.25	81%	96.0°
2027-04-17 Sat	0	—	unknown	—	72.5° 15:25	7.19	89%	110.0°
2027-04-18 Sun	0	—	unknown	—	72.5° 15:25	7.13	95%	123.8°
2027-04-19 Mon	0	—	unknown	—	72.5° 15:20	7.08	99%	137.5°
2027-04-20 Tue	0	—	unknown	—	72.5° 15:15	7.02	100%	150.9°
2027-04-21 Wed	0	—	unknown	—	72.5° 15:10	6.96	99%	164.0°
2027-04-22 Thu	0	—	unknown	—	72.5° 15:10	6.9	96%	176.8°
2027-04-23 Fri	0	—	unknown	—	72.5° 15:05	6.84	90%	170.5°
2027-04-24 Sat	0	—	unknown	—	72.5° 15:00	6.78	84%	158.2°
2027-04-25 Sun	0	—	unknown	—	72.5° 14:55	6.73	76%	146.1°
2027-04-26 Mon	0	—	unknown	—	72.5° 14:50	6.67	68%	134.1°
2027-04-27 Tue	0	—	unknown	—	72.5° 14:50	6.61	59%	122.3°
2027-04-28 Wed	0	—	unknown	—	72.5° 14:45	6.55	49%	110.4°
2027-04-29 Thu	0	—	unknown	—	72.5° 14:40	6.49	40%	98.5°
2027-04-30 Fri	0	—	unknown	—	72.5° 14:35	6.43	31%	86.4°
2027-05-01 Sat	0	—	unknown	—	72.5° 14:30	6.38	22%	74.1°
2027-05-02 Sun	0	—	unknown	—	72.5° 14:30	6.32	14%	61.5°
2027-05-03 Mon	0	—	unknown	—	72.5° 14:25	6.26	8%	48.5°
2027-05-04 Tue	0	—	unknown	—	72.5° 14:20	6.2	3%	35.1°
2027-05-05 Wed	0	—	unknown	—	72.5° 14:15	6.15	0%	21.4°
2027-05-06 Thu	0	—	unknown	—	72.5° 14:15	6.09	0%	7.4°
2027-05-07 Fri	0	—	unknown	—	72.5° 14:10	6.03	3%	6.9°
2027-05-08 Sat	0	—	unknown	—	72.5° 14:05	5.98	8%	21.3°
2027-05-09 Sun	0	—	unknown	—	72.5° 14:00	5.92	16%	35.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-04-10&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.