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 HD 189733: 10-10 (100), 10-11 (100), 10-12 (100), 10-13 (100), 10-14 (100) — by astronomy; check the weather when the night is within four days.

2026-10-10astronomy score per night — click a bar for that night2026-11-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-10-10 Sat	100	98	98	20:25–01:10 (good, 4.75 h)	71.1° 20:05	9.6	0%	106.0°
2026-10-11 Sun	100	0	0	—	71.1° 20:00	9.64	2%	96.9°
2026-10-12 Mon	100	0	0	—	71.1° 20:00	9.69	6%	87.9°
2026-10-13 Tue	100	0	0	—	71.1° 19:55	9.73	11%	79.0°
2026-10-14 Wed	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:50	9.78	17%	70.6°
2026-10-15 Thu	100	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:45	9.82	25%	62.7°
2026-10-16 Fri	97	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:40	9.86	34%	55.7°
2026-10-17 Sat	90	—	unknown	20:10–00:45 (good, 4.58 h)	71.1° 19:40	9.91	43%	49.9°
2026-10-18 Sun	77	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:35	9.95	52%	45.7°
2026-10-19 Mon	57	—	unknown	20:10–00:10 (good, 4.0 h)	71.1° 19:30	9.99	62%	43.8°
2026-10-20 Tue	46	—	unknown	20:10–21:55 (good, 1.75 h)	71.1° 19:25	10.03	71%	44.4°
2026-10-21 Wed	39	—	unknown	20:05–00:45 (marginal, 4.67 h)	71.1° 19:20	10.08	80%	47.8°
2026-10-22 Thu	35	—	unknown	20:05–00:35 (marginal, 4.5 h)	71.1° 19:20	10.12	87%	53.5°
2026-10-23 Fri	35	—	unknown	20:05–00:25 (marginal, 4.33 h)	71.1° 19:15	10.16	94%	61.1°
2026-10-24 Sat	40	—	unknown	20:00–20:45 (good, 0.75 h)	71.1° 19:10	10.2	98%	70.0°
2026-10-25 Sun	47	—	unknown	19:00–20:40 (good, 1.67 h)	71.1° 18:05	10.24	100%	79.9°
2026-10-26 Mon	58	—	unknown	19:00–21:40 (good, 2.67 h)	71.1° 18:05	10.28	99%	90.3°
2026-10-27 Tue	70	—	unknown	19:00–22:40 (good, 3.67 h)	71.1° 18:00	10.31	96%	100.8°
2026-10-28 Wed	83	—	unknown	18:55–22:45 (good, 3.83 h)	71.1° 17:55	10.35	90%	111.0°
2026-10-29 Thu	99	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:50	10.39	81%	120.3°
2026-10-30 Fri	100	—	unknown	18:55–22:45 (good, 3.83 h)	71.1° 17:45	10.43	71%	128.2°
2026-10-31 Sat	100	—	unknown	18:55–22:45 (good, 3.83 h)	71.1° 17:45	10.47	60%	133.9°
2026-11-01 Sun	100	—	unknown	18:50–22:45 (good, 3.92 h)	71.1° 17:40	10.5	49%	136.4°
2026-11-02 Mon	100	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:35	10.54	38%	135.4°
2026-11-03 Tue	99	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:30	10.57	28%	131.3°
2026-11-04 Wed	98	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:25	10.61	19%	125.0°
2026-11-05 Thu	96	—	unknown	18:50–22:30 (good, 3.67 h)	71.1° 17:25	10.64	12%	117.2°
2026-11-06 Fri	96	—	unknown	18:45–22:25 (good, 3.67 h)	71.1° 17:20	10.68	6%	108.6°
2026-11-07 Sat	94	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:15	10.71	2%	99.7°
2026-11-08 Sun	93	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:10	10.74	0%	90.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-10-10&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.