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: 06-27 (100), 06-28 (100), 06-29 (100), 06-30 (100), 07-01 (100) — by astronomy; check the weather when the night is within four days.

2046-06-18astronomy score per night — click a bar for that night2046-07-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-06-18 Mon	46	—	unknown	03:35–03:40 (good, 0.08 h)	71.1° 03:35	4.43	100%	55.6°
2046-06-19 Tue	40	—	unknown	23:10–03:40 (marginal, 4.5 h)	71.1° 03:30	4.42	98%	48.6°
2046-06-20 Wed	41	—	unknown	23:15–03:40 (marginal, 4.42 h)	71.1° 03:25	4.42	94%	43.7°
2046-06-21 Thu	66	—	unknown	23:15–23:20 (good, 0.08 h)	71.1° 03:20	4.42	88%	41.7°
2046-06-22 Fri	76	—	unknown	23:15–02:10 (good, 2.92 h)	71.1° 03:20	4.43	81%	42.5°
2046-06-23 Sat	87	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:15	4.43	73%	46.1°
2046-06-24 Sun	94	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.44	64%	51.6°
2046-06-25 Mon	97	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.45	55%	58.5°
2046-06-26 Tue	99	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.46	45%	66.3°
2046-06-27 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.47	36%	74.8°
2046-06-28 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.48	27%	83.8°
2046-06-29 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:50	4.5	19%	93.0°
2046-06-30 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.52	11%	102.4°
2046-07-01 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.54	6%	111.8°
2046-07-02 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:40	4.56	2%	120.8°
2046-07-03 Tue	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:35	4.59	0%	128.8°
2046-07-04 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.61	1%	135.0°
2046-07-05 Thu	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:25	4.64	4%	138.2°
2046-07-06 Fri	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:25	4.67	11%	137.5°
2046-07-07 Sat	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:20	4.7	19%	133.1°
2046-07-08 Sun	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:15	4.74	29%	125.9°
2046-07-09 Mon	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:10	4.77	40%	117.0°
2046-07-10 Tue	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:10	4.81	51%	107.1°
2046-07-11 Wed	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.84	62%	96.8°
2046-07-12 Thu	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:00	4.88	73%	86.5°
2046-07-13 Fri	100	—	unknown	23:00–03:55 (good, 4.92 h)	71.1° 01:55	4.92	82%	76.4°
2046-07-14 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:50	4.96	90%	66.8°
2046-07-15 Sun	98	—	unknown	23:40–04:00 (good, 4.33 h)	71.1° 01:50	5.01	95%	58.0°
2046-07-16 Mon	53	—	unknown	03:10–04:00 (good, 0.83 h)	71.1° 01:45	5.05	99%	50.6°
2046-07-17 Tue	43	—	unknown	22:55–04:05 (marginal, 5.17 h)	71.1° 01:40	5.09	100%	45.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-06-18&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.