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: 11-22 (69), 11-23 (69), 11-24 (68), 11-21 (67), 11-25 (66) — by astronomy; check the weather when the night is within four days.

2040-11-20astronomy score per night — click a bar for that night2040-12-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-11-20 Tue	62	—	unknown	18:35–21:20 (good, 2.75 h)	71.1° 16:25	11.11	95%	119.6°
2040-11-21 Wed	67	—	unknown	18:35–21:15 (good, 2.67 h)	71.1° 16:20	11.13	90%	125.6°
2040-11-22 Thu	69	—	unknown	18:35–21:15 (good, 2.67 h)	71.1° 16:15	11.16	84%	129.9°
2040-11-23 Fri	69	—	unknown	18:35–21:10 (good, 2.58 h)	71.1° 16:10	11.18	76%	132.4°
2040-11-24 Sat	68	—	unknown	18:35–21:15 (good, 2.67 h)	71.1° 16:05	11.2	68%	132.6°
2040-11-25 Sun	66	—	unknown	18:35–21:10 (good, 2.58 h)	71.1° 16:05	11.23	59%	130.6°
2040-11-26 Mon	65	—	unknown	18:35–21:05 (good, 2.5 h)	71.1° 16:00	11.25	50%	126.7°
2040-11-27 Tue	63	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 15:55	11.27	40%	121.1°
2040-11-28 Wed	61	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 15:50	11.29	31%	114.2°
2040-11-29 Thu	59	—	unknown	18:35–20:55 (good, 2.33 h)	71.1° 15:45	11.31	22%	106.4°
2040-11-30 Fri	57	—	unknown	18:35–20:50 (good, 2.25 h)	71.1° 15:45	11.32	14%	97.8°
2040-12-01 Sat	56	—	unknown	18:35–20:45 (good, 2.17 h)	71.1° 15:40	11.34	7%	88.7°
2040-12-02 Sun	54	—	unknown	18:35–20:40 (good, 2.08 h)	71.1° 15:35	11.36	2%	79.4°
2040-12-03 Mon	52	—	unknown	18:35–20:40 (good, 2.08 h)	71.1° 15:30	11.37	0%	70.2°
2040-12-04 Tue	50	—	unknown	18:35–20:35 (good, 2.0 h)	71.1° 15:30	11.39	1%	61.6°
2040-12-05 Wed	48	—	unknown	18:35–20:30 (good, 1.92 h)	71.1° 15:25	11.4	4%	54.3°
2040-12-06 Thu	46	—	unknown	18:35–20:25 (good, 1.83 h)	71.1° 15:20	11.42	10%	49.2°
2040-12-07 Fri	40	—	unknown	18:35–20:20 (good, 1.75 h)	71.1° 15:15	11.43	18%	47.2°
2040-12-08 Sat	34	—	unknown	18:35–20:10 (good, 1.58 h)	71.1° 15:10	11.44	27%	48.6°
2040-12-09 Sun	28	—	unknown	18:35–20:00 (good, 1.42 h)	71.1° 15:10	11.45	38%	52.9°
2040-12-10 Mon	24	—	unknown	18:35–19:45 (good, 1.17 h)	71.1° 15:05	11.46	49%	59.4°
2040-12-11 Tue	21	—	unknown	18:35–19:20 (good, 0.75 h)	71.1° 15:00	11.47	60%	67.2°
2040-12-12 Wed	19	—	unknown	18:35–18:55 (good, 0.33 h)	71.1° 14:55	11.48	71%	75.7°
2040-12-13 Thu	18	—	unknown	18:35–18:55 (good, 0.33 h)	71.1° 14:50	11.48	80%	84.5°
2040-12-14 Fri	19	—	unknown	18:35–19:10 (good, 0.58 h)	71.1° 14:50	11.49	88%	93.4°
2040-12-15 Sat	20	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 14:45	11.49	94%	102.0°
2040-12-16 Sun	22	—	unknown	18:35–19:30 (good, 0.92 h)	71.1° 14:40	11.5	98%	110.1°
2040-12-17 Mon	23	—	unknown	18:35–19:30 (good, 0.92 h)	71.1° 14:35	11.5	100%	117.5°
2040-12-18 Tue	23	—	unknown	18:35–19:30 (good, 0.92 h)	71.1° 14:35	11.51	100%	123.9°
2040-12-19 Wed	23	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 14:30	11.51	98%	128.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-11-20&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.