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: 08-21 (100), 08-22 (100), 08-23 (100), 08-24 (100), 08-25 (100) — by astronomy; check the weather when the night is within four days.

2046-08-16astronomy score per night — click a bar for that night2046-09-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-08-16 Thu	43	—	unknown	22:05–04:50 (marginal, 6.75 h)	71.1° 23:40	6.71	100%	43.6°
2046-08-17 Fri	48	—	unknown	22:05–04:45 (marginal, 6.67 h)	71.1° 23:40	6.77	98%	47.9°
2046-08-18 Sat	57	—	unknown	22:05–22:45 (good, 0.67 h)	71.1° 23:35	6.82	95%	54.1°
2046-08-19 Sun	70	—	unknown	22:00–00:20 (good, 2.33 h)	71.1° 23:30	6.88	90%	61.4°
2046-08-20 Mon	77	—	unknown	22:00–01:55 (good, 3.92 h)	71.1° 23:25	6.94	84%	69.5°
2046-08-21 Tue	100	—	unknown	21:55–03:00 (good, 5.08 h)	71.1° 23:20	7.0	76%	78.0°
2046-08-22 Wed	100	—	unknown	21:55–04:00 (good, 6.08 h)	71.1° 23:20	7.05	68%	86.9°
2046-08-23 Thu	100	—	unknown	21:55–04:05 (good, 6.17 h)	71.1° 23:15	7.11	58%	95.9°
2046-08-24 Fri	100	—	unknown	21:50–04:05 (good, 6.25 h)	71.1° 23:10	7.17	48%	105.0°
2046-08-25 Sat	100	—	unknown	21:50–04:10 (good, 6.33 h)	71.1° 23:05	7.23	38%	114.0°
2046-08-26 Sun	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:05	7.28	28%	122.5°
2046-08-27 Mon	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:00	7.34	19%	130.1°
2046-08-28 Tue	100	—	unknown	21:45–04:00 (good, 6.25 h)	71.1° 22:55	7.4	11%	135.8°
2046-08-29 Wed	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.45	5%	138.4°
2046-08-30 Thu	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:45	7.51	1%	136.9°
2046-08-31 Fri	100	—	unknown	21:35–03:50 (good, 6.25 h)	71.1° 22:45	7.56	0%	131.5°
2046-09-01 Sat	100	—	unknown	21:35–03:45 (good, 6.17 h)	71.1° 22:40	7.62	2%	123.2°
2046-09-02 Sun	100	—	unknown	21:35–03:40 (good, 6.08 h)	71.1° 22:35	7.68	7%	113.4°
2046-09-03 Mon	100	—	unknown	21:30–03:40 (good, 6.17 h)	71.1° 22:30	7.73	15%	102.7°
2046-09-04 Tue	100	—	unknown	21:30–03:35 (good, 6.08 h)	71.1° 22:25	7.79	24%	91.9°
2046-09-05 Wed	100	—	unknown	21:25–03:30 (good, 6.08 h)	71.1° 22:25	7.84	34%	81.3°
2046-09-06 Thu	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:20	7.9	45%	71.2°
2046-09-07 Fri	100	—	unknown	21:25–03:20 (good, 5.92 h)	71.1° 22:15	7.95	56%	62.0°
2046-09-08 Sat	95	—	unknown	21:20–03:20 (good, 6.0 h)	71.1° 22:10	8.01	66%	53.9°
2046-09-09 Sun	87	—	unknown	21:20–03:15 (good, 5.92 h)	71.1° 22:10	8.06	75%	47.5°
2046-09-10 Mon	67	—	unknown	02:55–03:10 (good, 0.25 h)	71.1° 22:05	8.11	83%	43.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-08-16&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.