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: 07-27 (100), 07-28 (100), 07-29 (100), 07-30 (100), 07-31 (100) — by astronomy; check the weather when the night is within four days.

2047-07-27astronomy score per night — click a bar for that night2047-08-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-07-27 Sat	100	—	unknown	22:45–04:20 (good, 5.58 h)	71.1° 01:00	5.57	28%	115.6°
2047-07-28 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 01:00	5.63	39%	105.3°
2047-07-29 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.2° 00:55	5.68	50%	94.6°
2047-07-30 Tue	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.2° 00:50	5.73	62%	83.7°
2047-07-31 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.2° 00:45	5.79	72%	73.0°
2047-08-01 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.84	82%	62.9°
2047-08-02 Fri	95	—	unknown	22:40–04:25 (good, 5.75 h)	71.1° 00:40	5.9	90%	53.7°
2047-08-03 Sat	85	—	unknown	04:25–04:30 (good, 0.08 h)	71.2° 00:35	5.95	96%	46.3°
2047-08-04 Sun	43	—	unknown	22:30–04:30 (marginal, 6.0 h)	71.2° 00:30	6.01	99%	41.4°
2047-08-05 Mon	40	—	unknown	22:30–04:30 (marginal, 6.0 h)	71.1° 00:25	6.07	100%	40.0°
2047-08-06 Tue	43	—	unknown	22:25–04:35 (marginal, 6.17 h)	71.1° 00:20	6.12	99%	42.2°
2047-08-07 Wed	51	—	unknown	22:25–22:30 (good, 0.08 h)	71.1° 00:20	6.18	95%	47.3°
2047-08-08 Thu	65	—	unknown	22:20–23:55 (good, 1.58 h)	71.2° 00:15	6.24	90%	54.2°
2047-08-09 Fri	75	—	unknown	22:20–02:05 (good, 3.75 h)	71.2° 00:10	6.29	83%	62.3°
2047-08-10 Sat	100	—	unknown	22:20–03:15 (good, 4.92 h)	71.1° 00:05	6.35	75%	70.9°
2047-08-11 Sun	100	—	unknown	22:15–04:20 (good, 6.08 h)	71.1° 00:05	6.41	67%	79.8°
2047-08-12 Mon	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.2° 00:00	6.47	57%	88.9°
2047-08-13 Tue	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.2° 23:55	6.52	48%	97.9°
2047-08-14 Wed	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.2° 23:50	6.58	39%	106.9°
2047-08-15 Thu	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:45	6.64	30%	115.7°
2047-08-16 Fri	100	—	unknown	22:05–04:50 (good, 6.75 h)	71.1° 23:45	6.7	21%	123.9°
2047-08-17 Sat	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.2° 23:40	6.75	13%	131.2°
2047-08-18 Sun	100	—	unknown	22:05–04:40 (good, 6.58 h)	71.2° 23:35	6.81	7%	136.9°
2047-08-19 Mon	100	—	unknown	22:00–04:40 (good, 6.67 h)	71.2° 23:30	6.87	3%	139.8°
2047-08-20 Tue	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:25	6.93	0%	139.1°
2047-08-21 Wed	100	—	unknown	21:55–04:30 (good, 6.58 h)	71.1° 23:25	6.98	0%	134.7°
2047-08-22 Thu	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.2° 23:20	7.04	3%	127.4°
2047-08-23 Fri	100	—	unknown	21:55–04:20 (good, 6.42 h)	71.2° 23:15	7.1	9%	118.2°
2047-08-24 Sat	100	—	unknown	21:50–04:20 (good, 6.5 h)	71.1° 23:10	7.15	16%	107.9°
2047-08-25 Sun	100	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.21	26%	97.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-07-27&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.