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: 12-12 (37), 12-13 (37), 12-14 (36), 12-09 (34), 12-10 (34) — by astronomy; check the weather when the night is within four days.

2030-12-02astronomy score per night — click a bar for that night2030-12-31

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-12-02 Mon	25	—	unknown	18:35–19:00 (good, 0.42 h)	71.1° 15:35	11.35	60%	53.6°
2030-12-03 Tue	22	—	unknown	18:35–21:00 (marginal, 2.42 h)	71.1° 15:35	11.36	70%	62.5°
2030-12-04 Wed	22	—	unknown	18:35–20:55 (marginal, 2.33 h)	71.1° 15:30	11.38	78%	71.8°
2030-12-05 Thu	22	—	unknown	18:35–18:50 (good, 0.25 h)	71.1° 15:25	11.39	86%	81.3°
2030-12-06 Fri	24	—	unknown	18:35–19:20 (good, 0.75 h)	71.1° 15:20	11.41	92%	90.9°
2030-12-07 Sat	27	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 15:20	11.42	96%	100.4°
2030-12-08 Sun	30	—	unknown	18:35–20:00 (good, 1.42 h)	71.1° 15:15	11.43	99%	109.6°
2030-12-09 Mon	34	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 15:10	11.44	100%	118.5°
2030-12-10 Tue	34	—	unknown	18:35–20:00 (good, 1.42 h)	71.1° 15:05	11.45	99%	126.6°
2030-12-11 Wed	34	—	unknown	18:35–20:00 (good, 1.42 h)	71.1° 15:00	11.46	96%	133.7°
2030-12-12 Thu	37	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 15:00	11.47	92%	139.2°
2030-12-13 Fri	37	—	unknown	18:35–20:00 (good, 1.42 h)	71.1° 14:55	11.48	86%	142.2°
2030-12-14 Sat	36	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 14:50	11.49	79%	142.0°
2030-12-15 Sun	34	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:45	11.49	70%	138.6°
2030-12-16 Mon	32	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:40	11.5	61%	132.6°
2030-12-17 Tue	31	—	unknown	18:35–19:45 (good, 1.17 h)	71.1° 14:40	11.5	51%	124.6°
2030-12-18 Wed	30	—	unknown	18:35–19:40 (good, 1.08 h)	71.1° 14:35	11.5	40%	115.2°
2030-12-19 Thu	28	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 14:30	11.51	30%	104.8°
2030-12-20 Fri	27	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 14:25	11.51	20%	93.7°
2030-12-21 Sat	25	—	unknown	18:35–19:30 (good, 0.92 h)	71.1° 14:25	11.51	11%	82.2°
2030-12-22 Sun	23	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 14:20	11.51	5%	70.5°
2030-12-23 Mon	22	—	unknown	18:40–19:20 (good, 0.67 h)	71.1° 14:15	11.51	1%	59.3°
2030-12-24 Tue	20	—	unknown	18:40–19:15 (good, 0.58 h)	71.1° 14:10	11.5	0%	49.3°
2030-12-25 Wed	19	—	unknown	18:40–19:15 (good, 0.58 h)	71.1° 14:05	11.5	2%	41.6°
2030-12-26 Thu	17	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:05	11.5	7%	37.8°
2030-12-27 Fri	14	—	unknown	18:40–19:00 (good, 0.33 h)	71.1° 14:00	11.49	14%	38.7°
2030-12-28 Sat	11	—	unknown	18:40–18:50 (good, 0.17 h)	71.1° 13:55	11.48	23%	43.6°
2030-12-29 Sun	8	—	unknown	18:10–19:25 (marginal, 1.25 h)	71.1° 13:50	11.48	33%	51.2°
2030-12-30 Mon	7	—	unknown	18:40–19:20 (marginal, 0.67 h)	71.1° 13:45	11.47	44%	60.0°
2030-12-31 Tue	5	—	unknown	18:45–19:15 (marginal, 0.5 h)	71.1° 13:45	11.46	54%	69.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-12-02&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.