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: 09-04 (100), 09-05 (100), 09-06 (100), 09-07 (100), 09-08 (100) — by astronomy; check the weather when the night is within four days.

2045-09-04astronomy score per night — click a bar for that night2045-10-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-09-04 Mon	100	—	unknown	21:30–03:25 (good, 5.92 h)	71.1° 22:25	7.8	44%	115.1°
2045-09-05 Tue	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:25	7.86	34%	123.6°
2045-09-06 Wed	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:20	7.91	23%	130.8°
2045-09-07 Thu	100	—	unknown	21:25–03:20 (good, 5.92 h)	71.1° 22:15	7.96	14%	135.5°
2045-09-08 Fri	100	—	unknown	21:20–03:15 (good, 5.92 h)	71.1° 22:10	8.02	7%	136.7°
2045-09-09 Sat	100	—	unknown	21:20–03:15 (good, 5.92 h)	71.1° 22:05	8.07	2%	133.8°
2045-09-10 Sun	100	—	unknown	21:15–03:10 (good, 5.92 h)	71.1° 22:05	8.13	0%	127.5°
2045-09-11 Mon	100	—	unknown	21:15–03:05 (good, 5.83 h)	71.1° 22:00	8.18	1%	119.0°
2045-09-12 Tue	100	—	unknown	21:15–03:00 (good, 5.75 h)	71.1° 21:55	8.23	5%	109.3°
2045-09-13 Wed	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:50	8.29	11%	99.1°
2045-09-14 Thu	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:45	8.34	20%	89.0°
2045-09-15 Fri	100	—	unknown	21:05–02:50 (good, 5.75 h)	71.1° 21:45	8.39	29%	79.3°
2045-09-16 Sat	100	—	unknown	21:05–02:45 (good, 5.67 h)	71.1° 21:40	8.45	39%	70.2°
2045-09-17 Sun	100	—	unknown	21:05–02:40 (good, 5.58 h)	71.1° 21:35	8.5	49%	61.9°
2045-09-18 Mon	96	—	unknown	21:00–02:40 (good, 5.67 h)	71.1° 21:30	8.55	58%	54.6°
2045-09-19 Tue	88	—	unknown	21:00–02:35 (good, 5.58 h)	71.1° 21:25	8.6	68%	48.8°
2045-09-20 Wed	75	—	unknown	20:55–01:25 (good, 4.5 h)	71.1° 21:25	8.65	76%	44.8°
2045-09-21 Thu	48	—	unknown	20:55–02:50 (marginal, 5.92 h)	71.1° 21:20	8.7	84%	43.2°
2045-09-22 Fri	41	—	unknown	20:55–02:35 (marginal, 5.67 h)	71.1° 21:15	8.75	90%	44.2°
2045-09-23 Sat	38	—	unknown	20:50–02:25 (marginal, 5.58 h)	71.1° 21:10	8.81	95%	47.5°
2045-09-24 Sun	38	—	unknown	20:50–02:15 (marginal, 5.42 h)	71.1° 21:10	8.86	98%	52.9°
2045-09-25 Mon	42	—	unknown	20:50–02:10 (marginal, 5.33 h)	71.1° 21:05	8.91	100%	59.7°
2045-09-26 Tue	51	—	unknown	20:45–21:55 (good, 1.17 h)	71.1° 21:00	8.96	100%	67.6°
2045-09-27 Wed	62	—	unknown	20:45–23:20 (good, 2.58 h)	71.1° 20:55	9.0	97%	76.2°
2045-09-28 Thu	75	—	unknown	20:45–00:15 (good, 3.5 h)	71.1° 20:50	9.05	93%	85.2°
2045-09-29 Fri	84	—	unknown	20:40–01:15 (good, 4.58 h)	71.1° 20:50	9.1	87%	94.5°
2045-09-30 Sat	100	—	unknown	20:40–01:30 (good, 4.83 h)	71.1° 20:45	9.15	79%	103.9°
2045-10-01 Sun	100	—	unknown	20:35–01:35 (good, 5.0 h)	71.1° 20:40	9.2	70%	113.0°
2045-10-02 Mon	100	—	unknown	20:35–01:35 (good, 5.0 h)	71.1° 20:35	9.25	59%	121.6°
2045-10-03 Tue	100	—	unknown	20:35–01:35 (good, 5.0 h)	71.1° 20:30	9.29	48%	129.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-09-04&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.