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: 09-20 (100), 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100) — by astronomy; check the weather when the night is within four days.

2046-09-11astronomy score per night — click a bar for that night2046-10-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-09-11 Tue	44	—	unknown	21:15–03:25 (marginal, 6.17 h)	71.1° 22:00	8.17	90%	41.5°
2046-09-12 Wed	38	—	unknown	21:15–03:10 (marginal, 5.92 h)	71.1° 21:55	8.22	95%	42.8°
2046-09-13 Thu	37	—	unknown	21:10–03:00 (marginal, 5.83 h)	71.1° 21:50	8.27	98%	46.6°
2046-09-14 Fri	40	—	unknown	21:10–02:50 (marginal, 5.67 h)	71.1° 21:50	8.33	100%	52.3°
2046-09-15 Sat	47	—	unknown	21:05–21:20 (good, 0.25 h)	71.1° 21:45	8.38	100%	59.4°
2046-09-16 Sun	57	—	unknown	21:05–22:40 (good, 1.58 h)	71.1° 21:40	8.43	97%	67.3°
2046-09-17 Mon	70	—	unknown	21:05–00:05 (good, 3.0 h)	71.1° 21:35	8.49	94%	75.8°
2046-09-18 Tue	80	—	unknown	21:00–01:05 (good, 4.08 h)	71.1° 21:30	8.54	88%	84.5°
2046-09-19 Wed	86	—	unknown	21:00–02:00 (good, 5.0 h)	71.1° 21:30	8.59	82%	93.5°
2046-09-20 Thu	100	—	unknown	21:00–02:15 (good, 5.25 h)	71.1° 21:25	8.64	73%	102.5°
2046-09-21 Fri	100	—	unknown	20:55–02:15 (good, 5.33 h)	71.1° 21:20	8.69	64%	111.4°
2046-09-22 Sat	100	—	unknown	20:55–02:15 (good, 5.33 h)	71.1° 21:15	8.74	54%	119.9°
2046-09-23 Sun	100	—	unknown	20:50–02:15 (good, 5.42 h)	71.1° 21:15	8.79	44%	127.7°
2046-09-24 Mon	100	—	unknown	20:50–02:15 (good, 5.42 h)	71.1° 21:10	8.84	33%	134.1°
2046-09-25 Tue	100	—	unknown	20:50–02:10 (good, 5.33 h)	71.1° 21:05	8.89	23%	137.9°
2046-09-26 Wed	100	—	unknown	20:45–02:05 (good, 5.33 h)	71.1° 21:00	8.94	14%	138.2°
2046-09-27 Thu	100	—	unknown	20:45–02:05 (good, 5.33 h)	71.1° 20:55	8.99	7%	134.4°
2046-09-28 Fri	100	—	unknown	20:45–02:00 (good, 5.25 h)	71.1° 20:55	9.04	2%	127.3°
2046-09-29 Sat	100	—	unknown	20:40–01:55 (good, 5.25 h)	71.1° 20:50	9.09	0%	118.0°
2046-09-30 Sun	100	—	unknown	20:40–01:50 (good, 5.17 h)	71.1° 20:45	9.14	1%	107.4°
2046-10-01 Mon	100	—	unknown	20:40–01:50 (good, 5.17 h)	71.1° 20:40	9.19	5%	96.3°
2046-10-02 Tue	100	—	unknown	20:35–01:45 (good, 5.17 h)	71.1° 20:35	9.24	12%	85.2°
2046-10-03 Wed	100	—	unknown	20:35–01:40 (good, 5.08 h)	71.1° 20:35	9.28	20%	74.5°
2046-10-04 Thu	100	—	unknown	20:30–01:35 (good, 5.08 h)	71.1° 20:30	9.33	30%	64.6°
2046-10-05 Fri	98	—	unknown	20:30–01:30 (good, 5.0 h)	71.1° 20:25	9.38	40%	55.9°
2046-10-06 Sat	90	—	unknown	20:30–01:30 (good, 5.0 h)	71.1° 20:20	9.42	51%	48.8°
2046-10-07 Sun	79	—	unknown	20:25–01:25 (good, 5.0 h)	71.1° 20:20	9.47	61%	43.8°
2046-10-08 Mon	52	—	unknown	20:25–23:25 (good, 3.0 h)	71.1° 20:15	9.52	70%	41.5°
2046-10-09 Tue	42	—	unknown	20:25–01:35 (marginal, 5.17 h)	71.1° 20:10	9.56	78%	42.0°
2046-10-10 Wed	36	—	unknown	20:20–01:25 (marginal, 5.08 h)	71.1° 20:05	9.61	86%	45.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-09-11&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.