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: 08-31 (100), 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100) — by astronomy; check the weather when the night is within four days.

2041-08-07astronomy score per night — click a bar for that night2041-09-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-08-07 Wed	43	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:00	6.2	77%	160.8°
2041-08-08 Thu	46	—	unknown	02:50–04:35 (good, 1.75 h)	72.5° 08:00	6.26	86%	146.9°
2041-08-09 Fri	47	—	unknown	02:55–04:40 (good, 1.75 h)	72.5° 07:55	6.32	93%	132.5°
2041-08-10 Sat	42	—	unknown	02:55–04:40 (good, 1.75 h)	72.5° 07:50	6.38	98%	117.7°
2041-08-11 Sun	35	—	unknown	03:00–04:40 (good, 1.67 h)	72.5° 07:45	6.43	100%	102.6°
2041-08-12 Mon	29	—	unknown	03:40–04:45 (good, 1.08 h)	72.5° 07:40	6.49	99%	87.4°
2041-08-13 Tue	22	—	unknown	02:15–04:45 (marginal, 2.5 h)	72.5° 07:40	6.55	95%	72.3°
2041-08-14 Wed	18	—	unknown	02:20–04:45 (marginal, 2.42 h)	72.5° 07:35	6.61	88%	57.3°
2041-08-15 Thu	16	—	unknown	02:20–04:50 (marginal, 2.5 h)	72.5° 07:30	6.66	79%	42.7°
2041-08-16 Fri	16	—	unknown	02:10–04:50 (marginal, 2.67 h)	72.5° 07:25	6.72	69%	28.5°
2041-08-17 Sat	23	—	unknown	01:55–04:50 (marginal, 2.92 h)	72.5° 07:20	6.78	59%	14.8°
2041-08-18 Sun	32	—	unknown	03:35–04:55 (good, 1.33 h)	72.5° 07:20	6.84	48%	2.6°
2041-08-19 Mon	42	—	unknown	02:30–04:55 (good, 2.42 h)	72.5° 07:15	6.89	38%	12.0°
2041-08-20 Tue	52	—	unknown	02:15–04:55 (good, 2.67 h)	72.5° 07:10	6.95	28%	24.5°
2041-08-21 Wed	63	—	unknown	02:00–04:55 (good, 2.92 h)	72.5° 07:05	7.01	20%	36.9°
2041-08-22 Thu	74	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 07:05	7.07	12%	49.1°
2041-08-23 Fri	80	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 07:00	7.12	7%	61.1°
2041-08-24 Sat	86	—	unknown	01:50–05:00 (good, 3.17 h)	72.5° 06:55	7.18	3%	73.0°
2041-08-25 Sun	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.5° 06:50	7.24	1%	84.9°
2041-08-26 Mon	90	—	unknown	01:40–05:05 (good, 3.42 h)	72.5° 06:45	7.29	0%	96.7°
2041-08-27 Tue	92	—	unknown	01:35–05:05 (good, 3.5 h)	72.5° 06:45	7.35	2%	108.5°
2041-08-28 Wed	95	—	unknown	01:35–05:05 (good, 3.5 h)	72.5° 06:40	7.41	5%	120.3°
2041-08-29 Thu	97	—	unknown	01:30–05:10 (good, 3.67 h)	72.5° 06:35	7.46	9%	132.2°
2041-08-30 Fri	98	—	unknown	01:25–05:10 (good, 3.75 h)	72.5° 06:30	7.52	16%	144.2°
2041-08-31 Sat	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.5° 06:25	7.58	23%	156.3°
2041-09-01 Sun	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.5° 06:25	7.63	32%	168.6°
2041-09-02 Mon	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.5° 06:20	7.69	42%	177.4°
2041-09-03 Tue	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.5° 06:15	7.74	52%	165.4°
2041-09-04 Wed	100	—	unknown	01:05–05:15 (good, 4.17 h)	72.5° 06:10	7.8	63%	152.1°
2041-09-05 Thu	100	—	unknown	01:05–05:20 (good, 4.25 h)	72.5° 06:10	7.85	73%	138.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-08-07&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.