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: 11-27 (61), 11-28 (61), 11-29 (60), 11-30 (58), 11-26 (56) — by astronomy; check the weather when the night is within four days.

2026-11-20astronomy score per night — click a bar for that night2026-12-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-11-20 Fri	29	—	unknown	18:35–18:45 (good, 0.17 h)	71.1° 16:25	11.09	82%	65.9°
2026-11-21 Sat	29	—	unknown	18:35–19:00 (good, 0.42 h)	71.1° 16:20	11.12	90%	75.4°
2026-11-22 Sun	33	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 16:15	11.14	96%	85.6°
2026-11-23 Mon	39	—	unknown	18:35–20:20 (good, 1.75 h)	71.1° 16:15	11.17	99%	96.3°
2026-11-24 Tue	46	—	unknown	18:35–20:55 (good, 2.33 h)	71.1° 16:10	11.19	100%	106.9°
2026-11-25 Wed	53	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 16:05	11.21	97%	117.0°
2026-11-26 Thu	56	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 16:00	11.23	92%	125.9°
2026-11-27 Fri	61	—	unknown	18:35–20:55 (good, 2.33 h)	71.1° 15:55	11.26	84%	132.6°
2026-11-28 Sat	61	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 15:55	11.28	75%	136.2°
2026-11-29 Sun	60	—	unknown	18:35–20:55 (good, 2.33 h)	71.1° 15:50	11.3	65%	136.2°
2026-11-30 Mon	58	—	unknown	18:35–20:50 (good, 2.25 h)	71.1° 15:45	11.31	54%	132.7°
2026-12-01 Tue	56	—	unknown	18:35–20:45 (good, 2.17 h)	71.1° 15:40	11.33	43%	126.7°
2026-12-02 Wed	54	—	unknown	18:35–20:45 (good, 2.17 h)	71.1° 15:35	11.35	33%	119.2°
2026-12-03 Thu	53	—	unknown	18:35–20:40 (good, 2.08 h)	71.1° 15:35	11.36	23%	110.8°
2026-12-04 Fri	51	—	unknown	18:35–20:35 (good, 2.0 h)	71.1° 15:30	11.38	16%	102.0°
2026-12-05 Sat	50	—	unknown	18:35–20:30 (good, 1.92 h)	71.1° 15:25	11.39	9%	93.0°
2026-12-06 Sun	48	—	unknown	18:35–20:30 (good, 1.92 h)	71.1° 15:20	11.41	4%	84.1°
2026-12-07 Mon	46	—	unknown	18:35–20:25 (good, 1.83 h)	71.1° 15:20	11.42	1%	75.4°
2026-12-08 Tue	44	—	unknown	18:35–20:20 (good, 1.75 h)	71.1° 15:15	11.43	0%	67.1°
2026-12-09 Wed	43	—	unknown	18:35–20:15 (good, 1.67 h)	71.1° 15:10	11.44	1%	59.5°
2026-12-10 Thu	42	—	unknown	18:35–20:10 (good, 1.58 h)	71.1° 15:05	11.45	3%	52.8°
2026-12-11 Fri	39	—	unknown	18:35–20:10 (good, 1.58 h)	71.1° 15:00	11.46	7%	47.5°
2026-12-12 Sat	35	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 15:00	11.47	13%	44.2°
2026-12-13 Sun	30	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 14:55	11.48	20%	43.2°
2026-12-14 Mon	26	—	unknown	18:35–19:45 (good, 1.17 h)	71.1° 14:50	11.49	28%	44.8°
2026-12-15 Tue	22	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 14:45	11.49	37%	48.9°
2026-12-16 Wed	18	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 14:40	11.5	47%	55.0°
2026-12-17 Thu	16	—	unknown	18:35–18:45 (good, 0.17 h)	71.1° 14:40	11.5	57%	62.6°
2026-12-18 Fri	14	—	unknown	18:35–20:05 (marginal, 1.5 h)	71.1° 14:35	11.5	67%	71.4°
2026-12-19 Sat	14	—	unknown	18:35–20:00 (marginal, 1.42 h)	71.1° 14:30	11.51	77%	81.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-11-20&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.