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: 10-15 (100), 10-16 (100), 10-17 (100), 10-18 (100), 10-19 (100) — by astronomy; check the weather when the night is within four days.

2039-10-15astronomy score per night — click a bar for that night2039-11-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-10-15 Sat	100	—	unknown	22:25–06:05 (good, 7.67 h)	72.5° 03:30	9.81	5%	117.4°
2039-10-16 Sun	100	—	unknown	22:20–06:05 (good, 7.75 h)	72.5° 03:30	9.86	1%	131.2°
2039-10-17 Mon	100	—	unknown	22:20–06:05 (good, 7.75 h)	72.5° 03:25	9.9	0%	145.4°
2039-10-18 Tue	100	—	unknown	22:15–06:05 (good, 7.83 h)	72.5° 03:20	9.94	2%	159.6°
2039-10-19 Wed	100	—	unknown	22:10–06:10 (good, 8.0 h)	72.5° 03:15	9.99	6%	172.7°
2039-10-20 Thu	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:15	10.03	13%	168.9°
2039-10-21 Fri	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:10	10.07	22%	155.2°
2039-10-22 Sat	100	—	unknown	22:00–06:10 (good, 8.17 h)	72.5° 03:05	10.11	32%	141.0°
2039-10-23 Sun	100	—	unknown	22:00–06:15 (good, 8.25 h)	72.5° 03:00	10.15	44%	126.9°
2039-10-24 Mon	100	—	unknown	22:00–06:15 (good, 8.25 h)	72.5° 02:55	10.19	55%	113.1°
2039-10-25 Tue	100	—	unknown	22:00–06:15 (good, 8.25 h)	72.5° 02:55	10.23	66%	99.5°
2039-10-26 Wed	100	—	unknown	22:05–06:15 (good, 8.17 h)	72.5° 02:50	10.27	75%	86.1°
2039-10-27 Thu	100	—	unknown	23:20–06:15 (good, 6.92 h)	72.5° 02:45	10.31	84%	73.0°
2039-10-28 Fri	98	—	unknown	01:45–06:20 (good, 4.58 h)	72.5° 02:40	10.35	91%	60.1°
2039-10-29 Sat	90	—	unknown	03:50–05:20 (good, 1.5 h)	72.5° 02:35	10.38	96%	47.4°
2039-10-30 Sun	44	—	unknown	22:35–05:20 (marginal, 6.75 h)	72.5° 01:35	10.42	99%	35.0°
2039-10-31 Mon	30	—	unknown	02:20–05:20 (marginal, 3.0 h)	72.5° 01:30	10.46	100%	22.8°
2039-11-01 Tue	25	—	unknown	03:20–05:20 (marginal, 2.0 h)	72.5° 01:25	10.5	99%	11.3°
2039-11-02 Wed	26	—	unknown	20:20–23:30 (marginal, 3.17 h)	72.5° 01:20	10.53	96%	5.7°
2039-11-03 Thu	34	—	unknown	20:05–01:05 (marginal, 5.0 h)	72.5° 01:20	10.57	92%	15.0°
2039-11-04 Fri	45	—	unknown	19:50–05:25 (marginal, 9.58 h)	72.5° 01:15	10.6	86%	26.4°
2039-11-05 Sat	66	—	unknown	20:05–20:15 (good, 0.17 h)	72.5° 01:10	10.64	79%	38.0°
2039-11-06 Sun	85	—	unknown	20:00–01:30 (good, 5.5 h)	72.5° 01:05	10.67	71%	49.8°
2039-11-07 Mon	92	—	unknown	19:55–04:20 (good, 8.42 h)	72.5° 01:00	10.71	62%	61.6°
2039-11-08 Tue	100	—	unknown	19:50–05:30 (good, 9.67 h)	72.5° 01:00	10.74	52%	73.7°
2039-11-09 Wed	100	—	unknown	19:50–05:30 (good, 9.67 h)	72.5° 00:55	10.77	42%	86.0°
2039-11-10 Thu	100	—	unknown	19:45–05:30 (good, 9.75 h)	72.5° 00:50	10.8	33%	98.6°
2039-11-11 Fri	100	—	unknown	19:40–05:35 (good, 9.92 h)	72.5° 00:45	10.83	23%	111.7°
2039-11-12 Sat	100	—	unknown	19:35–05:35 (good, 10.0 h)	72.5° 00:40	10.87	15%	125.2°
2039-11-13 Sun	100	—	unknown	19:30–05:35 (good, 10.08 h)	72.5° 00:40	10.9	8%	139.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-10-15&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.