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: 08-27 (100), 08-28 (100), 09-09 (100), 09-10 (100), 09-11 (100) — by astronomy; check the weather when the night is within four days.

2047-08-27astronomy score per night — click a bar for that night2047-09-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-08-27 Tue	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.2° 23:00	7.33	48%	75.3°
2047-08-28 Wed	100	—	unknown	21:45–04:00 (good, 6.25 h)	71.2° 22:55	7.38	59%	65.1°
2047-08-29 Thu	98	—	unknown	21:40–04:00 (good, 6.33 h)	71.1° 22:50	7.44	70%	55.8°
2047-08-30 Fri	89	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.49	80%	48.0°
2047-08-31 Sat	77	—	unknown	03:25–03:50 (good, 0.42 h)	71.2° 22:45	7.55	88%	42.4°
2047-09-01 Sun	42	—	unknown	21:35–04:05 (marginal, 6.5 h)	71.2° 22:40	7.61	94%	40.0°
2047-09-02 Mon	37	—	unknown	21:35–03:50 (marginal, 6.25 h)	71.2° 22:35	7.66	98%	41.1°
2047-09-03 Tue	38	—	unknown	21:30–03:35 (marginal, 6.08 h)	71.1° 22:30	7.72	100%	45.4°
2047-09-04 Wed	43	—	unknown	21:30–03:30 (marginal, 6.0 h)	71.1° 22:30	7.77	100%	51.8°
2047-09-05 Thu	53	—	unknown	21:30–22:10 (good, 0.67 h)	71.2° 22:25	7.83	97%	59.6°
2047-09-06 Fri	67	—	unknown	21:25–00:00 (good, 2.58 h)	71.2° 22:20	7.88	93%	68.1°
2047-09-07 Sat	77	—	unknown	21:25–01:10 (good, 3.75 h)	71.1° 22:15	7.94	88%	77.0°
2047-09-08 Sun	83	—	unknown	21:20–02:15 (good, 4.92 h)	71.1° 22:15	7.99	81%	86.0°
2047-09-09 Mon	100	—	unknown	21:20–02:50 (good, 5.5 h)	71.2° 22:10	8.05	73%	95.1°
2047-09-10 Tue	100	—	unknown	21:20–02:55 (good, 5.58 h)	71.2° 22:05	8.1	64%	104.1°
2047-09-11 Wed	100	—	unknown	21:15–03:00 (good, 5.75 h)	71.2° 22:00	8.16	55%	112.8°
2047-09-12 Thu	100	—	unknown	21:15–03:00 (good, 5.75 h)	71.1° 21:55	8.21	46%	121.2°
2047-09-13 Fri	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:55	8.26	36%	128.8°
2047-09-14 Sat	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.2° 21:50	8.32	27%	135.1°
2047-09-15 Sun	100	—	unknown	21:10–02:50 (good, 5.67 h)	71.2° 21:45	8.37	18%	139.2°
2047-09-16 Mon	100	—	unknown	21:05–02:50 (good, 5.75 h)	71.2° 21:40	8.42	10%	140.0°
2047-09-17 Tue	100	—	unknown	21:05–02:45 (good, 5.67 h)	71.1° 21:35	8.47	5%	137.0°
2047-09-18 Wed	100	—	unknown	21:00–02:40 (good, 5.67 h)	71.1° 21:35	8.52	1%	130.7°
2047-09-19 Thu	100	—	unknown	21:00–02:35 (good, 5.58 h)	71.2° 21:30	8.58	0%	121.9°
2047-09-20 Fri	100	—	unknown	21:00–02:30 (good, 5.5 h)	71.2° 21:25	8.63	2%	111.7°
2047-09-21 Sat	100	—	unknown	20:55–02:30 (good, 5.58 h)	71.1° 21:20	8.68	7%	100.6°
2047-09-22 Sun	100	—	unknown	20:55–02:25 (good, 5.5 h)	71.1° 21:20	8.73	14%	89.3°
2047-09-23 Mon	100	—	unknown	20:55–02:20 (good, 5.42 h)	71.2° 21:15	8.78	23%	78.1°
2047-09-24 Tue	100	—	unknown	20:50–02:15 (good, 5.42 h)	71.2° 21:10	8.83	34%	67.4°
2047-09-25 Wed	100	—	unknown	20:50–02:10 (good, 5.33 h)	71.2° 21:05	8.88	45%	57.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-08-27&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.