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: 07-14 (100), 07-15 (100), 07-16 (100), 07-17 (100), 07-18 (100) — by astronomy; check the weather when the night is within four days.

2047-07-10astronomy score per night — click a bar for that night2047-08-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-07-10 Wed	53	—	unknown	23:05–00:40 (good, 1.58 h)	71.1° 02:10	4.8	86%	43.7°
2047-07-11 Thu	88	—	unknown	23:05–02:25 (good, 3.33 h)	71.2° 02:05	4.83	78%	49.6°
2047-07-12 Fri	96	—	unknown	23:05–03:55 (good, 4.83 h)	71.2° 02:00	4.87	70%	56.9°
2047-07-13 Sat	98	—	unknown	23:00–03:55 (good, 4.92 h)	71.1° 01:55	4.91	60%	65.1°
2047-07-14 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:55	4.95	51%	73.8°
2047-07-15 Mon	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.2° 01:50	5.0	41%	82.8°
2047-07-16 Tue	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.2° 01:45	5.04	32%	91.8°
2047-07-17 Wed	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.2° 01:40	5.08	24%	100.9°
2047-07-18 Thu	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:35	5.13	16%	109.9°
2047-07-19 Fri	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:35	5.17	9%	118.6°
2047-07-20 Sat	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.2° 01:30	5.22	4%	126.7°
2047-07-21 Sun	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.2° 01:25	5.27	1%	133.5°
2047-07-22 Mon	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.32	0%	138.3°
2047-07-23 Tue	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.37	1%	140.0°
2047-07-24 Wed	100	—	unknown	22:50–04:15 (good, 5.42 h)	71.1° 01:15	5.42	5%	138.1°
2047-07-25 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.2° 01:10	5.47	10%	132.7°
2047-07-26 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.2° 01:05	5.52	18%	124.9°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-07-10&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.