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: 07-11 (2), 07-12 (2), 07-13 (2), 07-14 (2), 07-15 (2) — by astronomy; check the weather when the night is within four days.

2030-06-16astronomy score per night — click a bar for that night2030-07-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-06-16 Sun	0	—	unknown	—	72.5° 11:25	4.44	98%	137.3°
2030-06-17 Mon	0	—	unknown	—	72.5° 11:25	4.43	93%	122.6°
2030-06-18 Tue	0	—	unknown	—	72.5° 11:20	4.43	86%	108.3°
2030-06-19 Wed	0	—	unknown	—	72.5° 11:15	4.42	78%	94.5°
2030-06-20 Thu	0	—	unknown	—	72.5° 11:10	4.42	68%	81.1°
2030-06-21 Fri	0	—	unknown	—	72.5° 11:05	4.42	58%	68.2°
2030-06-22 Sat	0	—	unknown	—	72.5° 11:05	4.42	48%	55.6°
2030-06-23 Sun	0	—	unknown	—	72.5° 11:00	4.43	38%	43.4°
2030-06-24 Mon	0	—	unknown	—	72.5° 10:55	4.44	29%	31.3°
2030-06-25 Tue	0	—	unknown	—	72.5° 10:50	4.44	21%	19.5°
2030-06-26 Wed	0	—	unknown	—	72.5° 10:45	4.46	14%	7.9°
2030-06-27 Thu	0	—	unknown	—	72.5° 10:45	4.47	8%	5.1°
2030-06-28 Fri	0	—	unknown	—	72.5° 10:40	4.48	4%	16.4°
2030-06-29 Sat	0	—	unknown	—	72.5° 10:35	4.5	1%	28.2°
2030-06-30 Sun	0	—	unknown	—	72.5° 10:30	4.52	0%	40.2°
2030-07-01 Mon	0	—	unknown	—	72.5° 10:30	4.54	1%	52.4°
2030-07-02 Tue	0	—	unknown	—	72.5° 10:25	4.56	4%	64.7°
2030-07-03 Wed	0	—	unknown	—	72.5° 10:20	4.58	9%	77.2°
2030-07-04 Thu	0	—	unknown	—	72.5° 10:15	4.61	16%	90.0°
2030-07-05 Fri	0	—	unknown	—	72.5° 10:10	4.64	24%	102.9°
2030-07-06 Sat	0	—	unknown	—	72.5° 10:10	4.67	34%	116.1°
2030-07-07 Sun	1	—	unknown	—	72.5° 10:05	4.7	44%	129.6°
2030-07-08 Mon	1	—	unknown	—	72.5° 10:00	4.73	55%	143.3°
2030-07-09 Tue	1	—	unknown	—	72.5° 09:55	4.77	66%	157.3°
2030-07-10 Wed	1	—	unknown	—	72.5° 09:50	4.8	77%	171.5°
2030-07-11 Thu	2	—	unknown	—	72.5° 09:50	4.84	86%	172.9°
2030-07-12 Fri	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:45	4.88	93%	158.5°
2030-07-13 Sat	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:40	4.92	98%	143.7°
2030-07-14 Sun	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:35	4.96	100%	128.9°
2030-07-15 Mon	2	—	unknown	04:40–04:50 (marginal, 0.17 h)	72.5° 09:35	5.0	99%	114.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-06-16&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.