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: 12-10 (40), 12-11 (40), 12-12 (38), 12-08 (36), 12-09 (36) — by astronomy; check the weather when the night is within four days.

2041-12-03astronomy score per night — click a bar for that night2042-01-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2041-12-10 Tue	40	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 15:05	11.46	89%	131.7°
2041-12-11 Wed	40	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 15:00	11.47	82%	132.7°
2041-12-12 Thu	38	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 14:55	11.47	74%	131.3°
2041-12-13 Fri	36	—	unknown	18:35–20:00 (good, 1.42 h)	71.1° 14:55	11.48	65%	127.8°
2041-12-14 Sat	35	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 14:50	11.49	56%	122.7°
2041-12-15 Sun	34	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:45	11.49	47%	116.4°
2041-12-16 Mon	32	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:40	11.5	37%	109.2°
2041-12-17 Tue	31	—	unknown	18:35–19:45 (good, 1.17 h)	71.1° 14:40	11.5	28%	101.5°
2041-12-18 Wed	29	—	unknown	18:35–19:40 (good, 1.08 h)	71.1° 14:35	11.5	20%	93.3°
2041-12-19 Thu	28	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 14:30	11.51	13%	84.8°
2041-12-20 Fri	27	—	unknown	18:35–19:30 (good, 0.92 h)	71.1° 14:25	11.51	7%	76.2°
2041-12-21 Sat	25	—	unknown	18:35–19:30 (good, 0.92 h)	71.1° 14:20	11.51	2%	67.8°
2041-12-22 Sun	23	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 14:20	11.51	0%	60.1°
2041-12-23 Mon	21	—	unknown	18:40–19:20 (good, 0.67 h)	71.1° 14:15	11.51	1%	53.5°
2041-12-24 Tue	20	—	unknown	18:40–19:15 (good, 0.58 h)	71.1° 14:10	11.5	3%	49.0°
2041-12-25 Wed	18	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 14:05	11.5	9%	47.2°
2041-12-26 Thu	15	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:00	11.49	16%	48.7°
2041-12-27 Fri	12	—	unknown	18:40–18:55 (good, 0.25 h)	71.1° 14:00	11.49	26%	53.1°
2041-12-28 Sat	10	—	unknown	18:40–18:45 (good, 0.08 h)	71.1° 13:55	11.48	36%	59.8°
2041-12-29 Sun	8	—	unknown	18:40–19:25 (marginal, 0.75 h)	71.1° 13:50	11.48	48%	67.9°
2041-12-30 Mon	6	—	unknown	18:40–19:20 (marginal, 0.67 h)	71.1° 13:45	11.47	59%	76.8°
2041-12-31 Tue	5	—	unknown	18:45–19:15 (marginal, 0.5 h)	71.1° 13:40	11.46	70%	86.2°
2042-01-01 Wed	4	—	unknown	18:45–19:10 (marginal, 0.42 h)	71.1° 13:40	11.45	79%	95.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-12-03&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.