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: 08-14 (100), 08-15 (100), 08-16 (100), 08-17 (100), 08-18 (100) — by astronomy; check the weather when the night is within four days.

2033-08-13astronomy score per night — click a bar for that night2033-09-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-08-13 Sat	75	—	unknown	22:10–02:00 (good, 3.83 h)	71.1° 23:55	6.54	86%	65.3°
2033-08-14 Sun	100	—	unknown	22:10–03:25 (good, 5.25 h)	71.1° 23:50	6.6	77%	76.5°
2033-08-15 Mon	100	—	unknown	22:10–04:25 (good, 6.25 h)	71.1° 23:45	6.66	66%	87.8°
2033-08-16 Tue	100	—	unknown	22:05–04:35 (good, 6.5 h)	71.1° 23:40	6.72	55%	99.0°
2033-08-17 Wed	100	—	unknown	22:05–04:35 (good, 6.5 h)	71.1° 23:35	6.78	44%	109.8°
2033-08-18 Thu	100	—	unknown	22:05–04:35 (good, 6.5 h)	71.1° 23:35	6.83	34%	119.8°
2033-08-19 Fri	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.89	24%	128.8°
2033-08-20 Sat	100	—	unknown	22:00–04:30 (good, 6.5 h)	71.1° 23:25	6.95	16%	136.1°
2033-08-21 Sun	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:20	7.0	9%	140.9°
2033-08-22 Mon	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:15	7.06	4%	142.5°
2033-08-23 Tue	100	—	unknown	21:55–04:20 (good, 6.42 h)	71.1° 23:15	7.12	1%	140.6°
2033-08-24 Wed	100	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.18	0%	135.8°
2033-08-25 Thu	100	—	unknown	21:50–04:10 (good, 6.33 h)	71.1° 23:05	7.23	1%	129.0°
2033-08-26 Fri	100	—	unknown	21:45–04:10 (good, 6.42 h)	71.1° 23:00	7.29	4%	121.0°
2033-08-27 Sat	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:00	7.35	8%	112.4°
2033-08-28 Sun	100	—	unknown	21:45–04:00 (good, 6.25 h)	71.1° 22:55	7.4	14%	103.3°
2033-08-29 Mon	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.46	21%	94.0°
2033-08-30 Tue	100	—	unknown	21:40–03:50 (good, 6.17 h)	71.1° 22:45	7.52	30%	84.5°
2033-08-31 Wed	100	—	unknown	21:35–03:50 (good, 6.25 h)	71.1° 22:40	7.57	39%	75.1°
2033-09-01 Thu	100	—	unknown	21:35–03:45 (good, 6.17 h)	71.1° 22:40	7.63	48%	65.8°
2033-09-02 Fri	98	—	unknown	21:35–03:40 (good, 6.08 h)	71.1° 22:35	7.68	58%	56.8°
2033-09-03 Sat	92	—	unknown	21:30–03:35 (good, 6.08 h)	71.1° 22:30	7.74	68%	48.6°
2033-09-04 Sun	84	—	unknown	23:10–03:35 (good, 4.42 h)	71.1° 22:25	7.79	78%	41.9°
2033-09-05 Mon	47	—	unknown	21:25–03:55 (marginal, 6.5 h)	71.1° 22:20	7.85	86%	37.9°
2033-09-06 Tue	37	—	unknown	21:25–03:35 (marginal, 6.17 h)	71.1° 22:20	7.9	93%	38.1°
2033-09-07 Wed	35	—	unknown	21:25–03:20 (marginal, 5.92 h)	71.1° 22:15	7.96	98%	42.7°
2033-09-08 Thu	41	—	unknown	21:20–03:15 (marginal, 5.92 h)	71.1° 22:10	8.01	100%	50.8°
2033-09-09 Fri	53	—	unknown	21:20–22:05 (good, 0.75 h)	71.1° 22:05	8.07	99%	60.9°
2033-09-10 Sat	71	—	unknown	21:15–00:15 (good, 3.0 h)	71.1° 22:05	8.12	95%	72.3°
2033-09-11 Sun	81	—	unknown	21:15–01:35 (good, 4.33 h)	71.1° 22:00	8.18	88%	84.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-08-13&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.