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 V1057 Cyg: 05-27 (100), 05-28 (100), 05-29 (100), 05-30 (100), 05-31 (100) — by astronomy; check the weather when the night is within four days.

2030-05-22astronomy score per night — click a bar for that night2030-06-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-05-22 Wed	72	—	unknown	00:05–03:55 (good, 3.83 h)	87.3° 06:20	5.22	64%	55.9°
2030-05-23 Thu	81	—	unknown	00:00–03:55 (good, 3.92 h)	87.3° 06:15	5.17	53%	52.9°
2030-05-24 Fri	90	—	unknown	23:55–03:55 (good, 4.0 h)	87.3° 06:10	5.13	43%	52.2°
2030-05-25 Sat	95	—	unknown	23:50–03:55 (good, 4.08 h)	87.3° 06:05	5.08	33%	53.6°
2030-05-26 Sun	98	—	unknown	23:45–03:50 (good, 4.08 h)	87.3° 06:00	5.04	24%	56.9°
2030-05-27 Mon	100	—	unknown	23:45–03:50 (good, 4.08 h)	87.3° 06:00	4.99	16%	61.6°
2030-05-28 Tue	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.3° 05:55	4.95	10%	67.3°
2030-05-29 Wed	100	—	unknown	23:35–03:50 (good, 4.25 h)	87.3° 05:50	4.91	5%	73.8°
2030-05-30 Thu	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.3° 05:45	4.87	2%	80.7°
2030-05-31 Fri	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.3° 05:40	4.83	0%	87.9°
2030-06-01 Sat	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.3° 05:40	4.79	0%	95.2°
2030-06-02 Sun	100	—	unknown	23:20–03:45 (good, 4.42 h)	87.3° 05:35	4.76	2%	102.3°
2030-06-03 Mon	100	—	unknown	23:15–03:45 (good, 4.5 h)	87.3° 05:30	4.73	6%	109.2°
2030-06-04 Tue	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 05:25	4.69	12%	115.5°
2030-06-05 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 05:25	4.66	19%	120.9°
2030-06-06 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:20	4.63	28%	125.0°
2030-06-07 Fri	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:15	4.61	37%	127.4°
2030-06-08 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:10	4.58	48%	127.7°
2030-06-09 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:05	4.56	58%	125.5°
2030-06-10 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:05	4.53	69%	121.1°
2030-06-11 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 05:00	4.51	79%	114.8°
2030-06-12 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:55	4.5	88%	107.0°
2030-06-13 Thu	84	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:50	4.48	95%	98.2°
2030-06-14 Fri	73	—	unknown	23:20–03:40 (good, 4.33 h)	87.3° 04:45	4.46	99%	89.0°
2030-06-15 Sat	62	—	unknown	00:00–03:40 (good, 3.67 h)	87.3° 04:45	4.45	100%	79.8°
2030-06-16 Sun	54	—	unknown	00:40–03:40 (good, 3.0 h)	87.3° 04:40	4.44	98%	71.1°
2030-06-17 Mon	52	—	unknown	00:35–03:40 (good, 3.08 h)	87.3° 04:35	4.43	93%	63.6°
2030-06-18 Tue	71	—	unknown	23:10–03:20 (good, 4.17 h)	87.3° 04:30	4.43	86%	57.6°
2030-06-19 Wed	80	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:30	4.42	78%	53.7°
2030-06-20 Thu	90	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:25	4.42	68%	52.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-05-22&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.