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: 10-20 (98), 11-05 (97), 11-06 (97), 11-04 (96), 11-02 (95) — by astronomy; check the weather when the night is within four days.

2031-10-20astronomy score per night — click a bar for that night2031-11-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-10-20 Mon	98	—	unknown	20:10–00:35 (good, 4.42 h)	71.1° 19:25	10.02	24%	54.7°
2031-10-21 Tue	90	—	unknown	20:05–00:30 (good, 4.42 h)	71.1° 19:25	10.07	34%	46.0°
2031-10-22 Wed	75	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:20	10.11	46%	39.6°
2031-10-23 Thu	53	—	unknown	20:05–23:50 (good, 3.75 h)	71.1° 19:15	10.15	57%	37.0°
2031-10-24 Fri	41	—	unknown	20:00–00:40 (marginal, 4.67 h)	71.1° 19:10	10.19	68%	38.9°
2031-10-25 Sat	34	—	unknown	20:00–00:30 (marginal, 4.5 h)	71.1° 19:10	10.23	78%	44.6°
2031-10-26 Sun	32	—	unknown	19:00–23:15 (marginal, 4.25 h)	71.1° 18:05	10.27	87%	52.9°
2031-10-27 Mon	34	—	unknown	19:00–23:10 (marginal, 4.17 h)	71.1° 18:00	10.31	93%	62.6°
2031-10-28 Tue	41	—	unknown	18:55–20:00 (good, 1.08 h)	71.1° 17:55	10.34	98%	72.9°
2031-10-29 Wed	49	—	unknown	18:55–20:50 (good, 1.92 h)	71.1° 17:50	10.38	100%	83.5°
2031-10-30 Thu	59	—	unknown	18:55–21:45 (good, 2.83 h)	71.1° 17:50	10.42	100%	94.0°
2031-10-31 Fri	71	—	unknown	18:55–22:25 (good, 3.5 h)	71.1° 17:45	10.46	97%	104.3°
2031-11-01 Sat	81	—	unknown	18:55–22:30 (good, 3.58 h)	71.1° 17:40	10.49	93%	114.0°
2031-11-02 Sun	95	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:35	10.53	87%	123.0°
2031-11-03 Mon	95	—	unknown	18:50–22:30 (good, 3.67 h)	71.1° 17:30	10.57	80%	130.9°
2031-11-04 Tue	96	—	unknown	18:50–22:30 (good, 3.67 h)	71.1° 17:30	10.6	72%	137.4°
2031-11-05 Wed	97	—	unknown	18:50–22:25 (good, 3.58 h)	71.1° 17:25	10.64	63%	141.6°
2031-11-06 Thu	97	—	unknown	18:45–22:25 (good, 3.67 h)	71.1° 17:20	10.67	54%	143.0°
2031-11-07 Fri	95	—	unknown	18:45–22:25 (good, 3.67 h)	71.1° 17:15	10.7	44%	141.2°
2031-11-08 Sat	93	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:15	10.74	35%	136.6°
2031-11-09 Sun	92	—	unknown	18:45–22:15 (good, 3.5 h)	71.1° 17:10	10.77	26%	129.7°
2031-11-10 Mon	91	—	unknown	18:45–22:10 (good, 3.42 h)	71.1° 17:05	10.8	17%	121.3°
2031-11-11 Tue	89	—	unknown	18:45–22:05 (good, 3.33 h)	71.1° 17:00	10.83	10%	111.7°
2031-11-12 Wed	89	—	unknown	18:40–22:05 (good, 3.42 h)	71.1° 16:55	10.86	5%	101.4°
2031-11-13 Thu	87	—	unknown	18:40–22:00 (good, 3.33 h)	71.1° 16:55	10.89	1%	90.5°
2031-11-14 Fri	86	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 16:50	10.92	0%	79.4°
2031-11-15 Sat	84	—	unknown	18:40–21:50 (good, 3.17 h)	71.1° 16:45	10.95	1%	68.3°
2031-11-16 Sun	82	—	unknown	18:40–21:45 (good, 3.08 h)	71.1° 16:40	10.98	6%	57.6°
2031-11-17 Mon	75	—	unknown	18:40–21:45 (good, 3.08 h)	71.1° 16:35	11.01	12%	48.2°
2031-11-18 Tue	66	—	unknown	18:40–21:40 (good, 3.0 h)	71.1° 16:35	11.04	21%	40.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-10-20&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.