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: 11-20 (75), 11-21 (72), 11-22 (71), 11-23 (64), 11-24 (56) — by astronomy; check the weather when the night is within four days.

2044-11-20astronomy score per night — click a bar for that night2044-12-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-11-20 Sun	75	—	unknown	18:35–21:30 (good, 2.92 h)	71.1° 16:25	11.11	2%	68.4°
2044-11-21 Mon	72	—	unknown	18:35–21:25 (good, 2.83 h)	71.1° 16:20	11.14	5%	60.8°
2044-11-22 Tue	71	—	unknown	18:35–21:20 (good, 2.75 h)	71.1° 16:15	11.16	10%	54.2°
2044-11-23 Wed	64	—	unknown	18:35–21:15 (good, 2.67 h)	71.1° 16:10	11.18	16%	48.9°
2044-11-24 Thu	56	—	unknown	18:35–21:15 (good, 2.67 h)	71.1° 16:05	11.2	24%	45.5°
2044-11-25 Fri	48	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 16:05	11.23	32%	44.3°
2044-11-26 Sat	41	—	unknown	18:35–20:45 (good, 2.17 h)	71.1° 16:00	11.25	41%	45.7°
2044-11-27 Sun	34	—	unknown	18:35–20:30 (good, 1.92 h)	71.1° 15:55	11.27	51%	49.4°
2044-11-28 Mon	29	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 15:50	11.29	61%	55.1°
2044-11-29 Tue	25	—	unknown	18:35–18:50 (good, 0.25 h)	71.1° 15:45	11.31	70%	62.3°
2044-11-30 Wed	24	—	unknown	18:35–18:40 (good, 0.08 h)	71.1° 15:45	11.32	80%	70.8°
2044-12-01 Thu	24	—	unknown	18:35–18:50 (good, 0.25 h)	71.1° 15:40	11.34	88%	80.2°
2044-12-02 Fri	27	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 15:35	11.36	94%	90.2°
2044-12-03 Sat	30	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 15:30	11.37	98%	100.5°
2044-12-04 Sun	35	—	unknown	18:35–20:15 (good, 1.67 h)	71.1° 15:30	11.39	100%	110.7°
2044-12-05 Mon	39	—	unknown	18:35–20:20 (good, 1.75 h)	71.1° 15:25	11.4	98%	120.1°
2044-12-06 Tue	40	—	unknown	18:35–20:15 (good, 1.67 h)	71.1° 15:20	11.42	94%	128.1°
2044-12-07 Wed	44	—	unknown	18:35–20:15 (good, 1.67 h)	71.1° 15:15	11.43	88%	133.6°
2044-12-08 Thu	44	—	unknown	18:35–20:20 (good, 1.75 h)	71.1° 15:10	11.44	79%	135.7°
2044-12-09 Fri	42	—	unknown	18:35–20:15 (good, 1.67 h)	71.1° 15:10	11.45	68%	134.1°
2044-12-10 Sat	41	—	unknown	18:35–20:10 (good, 1.58 h)	71.1° 15:05	11.46	58%	129.4°
2044-12-11 Sun	39	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 15:00	11.47	47%	122.5°
2044-12-12 Mon	38	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 14:55	11.48	36%	114.5°
2044-12-13 Tue	36	—	unknown	18:35–20:00 (good, 1.42 h)	71.1° 14:50	11.48	26%	105.8°
2044-12-14 Wed	35	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 14:50	11.49	18%	96.8°
2044-12-15 Thu	34	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:45	11.49	11%	87.8°
2044-12-16 Fri	32	—	unknown	18:35–19:45 (good, 1.17 h)	71.1° 14:40	11.5	6%	79.0°
2044-12-17 Sat	31	—	unknown	18:35–19:45 (good, 1.17 h)	71.1° 14:35	11.5	2%	70.6°
2044-12-18 Sun	29	—	unknown	18:35–19:40 (good, 1.08 h)	71.1° 14:35	11.51	0%	62.8°
2044-12-19 Mon	27	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 14:30	11.51	0%	55.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-11-20&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.