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: 09-17 (100), 09-18 (100), 09-19 (100), 09-20 (100), 09-21 (100) — by astronomy; check the weather when the night is within four days.

2044-09-17astronomy score per night — click a bar for that night2044-10-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-09-17 Sat	100	—	unknown	21:05–02:40 (good, 5.58 h)	71.1° 21:35	8.51	16%	135.0°
2044-09-18 Sun	100	—	unknown	21:00–02:35 (good, 5.58 h)	71.1° 21:30	8.56	8%	134.2°
2044-09-19 Mon	100	—	unknown	21:00–02:35 (good, 5.58 h)	71.1° 21:25	8.61	3%	130.2°
2044-09-20 Tue	100	—	unknown	20:55–02:30 (good, 5.58 h)	71.1° 21:25	8.67	0%	123.6°
2044-09-21 Wed	100	—	unknown	20:55–02:25 (good, 5.5 h)	71.1° 21:20	8.72	0%	115.5°
2044-09-22 Thu	100	—	unknown	20:55–02:20 (good, 5.42 h)	71.1° 21:15	8.77	3%	106.7°
2044-09-23 Fri	100	—	unknown	20:50–02:15 (good, 5.42 h)	71.1° 21:10	8.82	7%	97.6°
2044-09-24 Sat	100	—	unknown	20:50–02:15 (good, 5.42 h)	71.1° 21:05	8.87	13%	88.5°
2044-09-25 Sun	100	—	unknown	20:50–02:10 (good, 5.33 h)	71.1° 21:05	8.92	21%	79.6°
2044-09-26 Mon	100	—	unknown	20:45–02:05 (good, 5.33 h)	71.1° 21:00	8.97	29%	71.2°
2044-09-27 Tue	100	—	unknown	20:45–02:00 (good, 5.25 h)	71.1° 20:55	9.02	38%	63.5°
2044-09-28 Wed	98	—	unknown	20:40–01:55 (good, 5.25 h)	71.1° 20:50	9.07	48%	56.6°
2044-09-29 Thu	90	—	unknown	20:40–01:55 (good, 5.25 h)	71.1° 20:45	9.11	57%	50.9°
2044-09-30 Fri	82	—	unknown	20:40–01:50 (good, 5.17 h)	71.1° 20:45	9.16	66%	46.8°
2044-10-01 Sat	55	—	unknown	20:35–23:45 (good, 3.17 h)	71.1° 20:40	9.21	75%	44.9°
2044-10-02 Sun	45	—	unknown	20:35–02:00 (marginal, 5.42 h)	71.1° 20:35	9.26	83%	45.5°
2044-10-03 Mon	40	—	unknown	20:35–01:50 (marginal, 5.25 h)	71.1° 20:30	9.31	90%	48.6°
2044-10-04 Tue	38	—	unknown	20:30–01:40 (marginal, 5.17 h)	71.1° 20:30	9.35	95%	53.9°
2044-10-05 Wed	41	—	unknown	20:30–01:30 (marginal, 5.0 h)	71.1° 20:25	9.4	99%	61.0°
2044-10-06 Thu	47	—	unknown	20:30–21:35 (good, 1.08 h)	71.1° 20:20	9.45	100%	69.3°
2044-10-07 Fri	58	—	unknown	20:25–22:45 (good, 2.33 h)	71.1° 20:15	9.49	99%	78.6°
2044-10-08 Sat	70	—	unknown	20:25–23:45 (good, 3.33 h)	71.1° 20:10	9.54	96%	88.3°
2044-10-09 Sun	84	—	unknown	20:25–00:45 (good, 4.33 h)	71.1° 20:10	9.58	90%	98.2°
2044-10-10 Mon	100	—	unknown	20:20–00:55 (good, 4.58 h)	71.1° 20:05	9.63	82%	108.0°
2044-10-11 Tue	100	—	unknown	20:20–00:55 (good, 4.58 h)	71.1° 20:00	9.67	72%	117.1°
2044-10-12 Wed	100	—	unknown	20:20–00:55 (good, 4.58 h)	71.1° 19:55	9.72	61%	125.1°
2044-10-13 Thu	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:50	9.76	50%	131.3°
2044-10-14 Fri	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:50	9.81	39%	134.8°
2044-10-15 Sat	100	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:45	9.85	28%	134.9°
2044-10-16 Sun	100	—	unknown	20:10–00:45 (good, 4.58 h)	71.1° 19:40	9.89	18%	131.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-09-17&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.