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: 11-12 (86), 11-13 (86), 11-11 (85), 11-14 (85), 11-15 (83) — by astronomy; check the weather when the night is within four days.

2041-11-10astronomy score per night — click a bar for that night2041-12-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-11-10 Sun	75	—	unknown	18:45–22:00 (good, 3.25 h)	71.1° 17:05	10.82	91%	118.6°
2041-11-11 Mon	85	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 17:00	10.85	84%	125.1°
2041-11-12 Tue	86	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 16:55	10.88	76%	129.8°
2041-11-13 Wed	86	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 16:50	10.91	67%	132.2°
2041-11-14 Thu	85	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 16:45	10.94	57%	132.3°
2041-11-15 Fri	83	—	unknown	18:40–21:50 (good, 3.17 h)	71.1° 16:45	10.97	48%	130.2°
2041-11-16 Sat	82	—	unknown	18:40–21:45 (good, 3.08 h)	71.1° 16:40	11.0	38%	126.1°
2041-11-17 Sun	80	—	unknown	18:40–21:40 (good, 3.0 h)	71.1° 16:35	11.03	29%	120.6°
2041-11-18 Mon	79	—	unknown	18:35–21:40 (good, 3.08 h)	71.1° 16:30	11.05	21%	113.9°
2041-11-19 Tue	77	—	unknown	18:35–21:35 (good, 3.0 h)	71.1° 16:30	11.08	14%	106.5°
2041-11-20 Wed	75	—	unknown	18:35–21:30 (good, 2.92 h)	71.1° 16:25	11.1	8%	98.5°
2041-11-21 Thu	74	—	unknown	18:35–21:25 (good, 2.83 h)	71.1° 16:20	11.13	3%	90.2°
2041-11-22 Fri	72	—	unknown	18:35–21:20 (good, 2.75 h)	71.1° 16:15	11.15	1%	81.6°
2041-11-23 Sat	70	—	unknown	18:35–21:20 (good, 2.75 h)	71.1° 16:10	11.18	0%	73.1°
2041-11-24 Sun	68	—	unknown	18:35–21:15 (good, 2.67 h)	71.1° 16:10	11.2	2%	65.0°
2041-11-25 Mon	67	—	unknown	18:35–21:10 (good, 2.58 h)	71.1° 16:05	11.22	6%	57.8°
2041-11-26 Tue	63	—	unknown	18:35–21:05 (good, 2.5 h)	71.1° 16:00	11.24	12%	51.9°
2041-11-27 Wed	56	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 15:55	11.26	20%	48.3°
2041-11-28 Thu	47	—	unknown	18:35–20:50 (good, 2.25 h)	71.1° 15:50	11.28	29%	47.4°
2041-11-29 Fri	39	—	unknown	18:35–20:40 (good, 2.08 h)	71.1° 15:50	11.3	40%	49.7°
2041-11-30 Sat	33	—	unknown	18:35–20:25 (good, 1.83 h)	71.1° 15:45	11.32	51%	54.6°
2041-12-01 Sun	28	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 15:40	11.34	62%	61.6°
2041-12-02 Mon	25	—	unknown	18:35–19:05 (good, 0.5 h)	71.1° 15:35	11.35	73%	69.9°
2041-12-03 Tue	24	—	unknown	18:35–19:05 (good, 0.5 h)	71.1° 15:35	11.37	83%	79.1°
2041-12-04 Wed	25	—	unknown	18:35–19:20 (good, 0.75 h)	71.1° 15:30	11.38	90%	88.6°
2041-12-05 Thu	28	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 15:25	11.4	96%	98.1°
2041-12-06 Fri	31	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 15:20	11.41	99%	107.2°
2041-12-07 Sat	34	—	unknown	18:35–20:10 (good, 1.58 h)	71.1° 15:15	11.42	100%	115.6°
2041-12-08 Sun	36	—	unknown	18:35–20:10 (good, 1.58 h)	71.1° 15:15	11.44	98%	122.8°
2041-12-09 Mon	36	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 15:10	11.45	94%	128.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-11-10&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.