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: 05-20 (100), 05-21 (100), 05-22 (100), 05-23 (100), 05-24 (100) — by astronomy; check the weather when the night is within four days.

2047-05-17astronomy score per night — click a bar for that night2047-06-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-05-17 Fri	85	—	unknown	00:25–04:05 (good, 3.67 h)	87.2° 06:40	5.48	38%	53.3°
2047-05-18 Sat	92	—	unknown	00:20–04:05 (good, 3.75 h)	87.2° 06:35	5.42	29%	53.8°
2047-05-19 Sun	96	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:30	5.37	21%	56.1°
2047-05-20 Mon	100	—	unknown	00:10–04:00 (good, 3.83 h)	87.2° 06:25	5.32	14%	60.0°
2047-05-21 Tue	100	—	unknown	00:10–04:00 (good, 3.83 h)	87.2° 06:25	5.27	8%	65.0°
2047-05-22 Wed	100	—	unknown	00:05–03:55 (good, 3.83 h)	87.2° 06:20	5.23	4%	70.9°
2047-05-23 Thu	100	—	unknown	00:00–03:55 (good, 3.92 h)	87.2° 06:15	5.18	1%	77.4°
2047-05-24 Fri	100	—	unknown	23:55–03:55 (good, 4.0 h)	87.2° 06:10	5.13	0%	84.5°
2047-05-25 Sat	100	—	unknown	23:50–03:55 (good, 4.08 h)	87.2° 06:05	5.09	1%	91.7°
2047-05-26 Sun	100	—	unknown	23:50–03:50 (good, 4.0 h)	87.2° 06:05	5.04	4%	99.0°
2047-05-27 Mon	100	—	unknown	23:45–03:50 (good, 4.08 h)	87.2° 06:00	5.0	9%	106.1°
2047-05-28 Tue	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:55	4.96	16%	112.8°
2047-05-29 Wed	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:50	4.91	24%	118.6°
2047-05-30 Thu	100	—	unknown	23:35–03:45 (good, 4.17 h)	87.2° 05:45	4.87	33%	123.3°
2047-05-31 Fri	100	—	unknown	23:35–03:45 (good, 4.17 h)	87.2° 05:45	4.84	44%	126.1°
2047-06-01 Sat	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.2° 05:40	4.8	55%	126.8°
2047-06-02 Sun	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.2° 05:35	4.76	66%	124.9°
2047-06-03 Mon	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.2° 05:30	4.73	77%	120.6°
2047-06-04 Tue	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.2° 05:30	4.7	86%	114.4°
2047-06-05 Wed	88	—	unknown	23:30–03:40 (good, 4.17 h)	87.2° 05:25	4.67	93%	106.7°
2047-06-06 Thu	80	—	unknown	23:30–03:40 (good, 4.17 h)	87.2° 05:20	4.64	98%	98.2°
2047-06-07 Fri	69	—	unknown	23:35–03:40 (good, 4.08 h)	87.2° 05:15	4.61	100%	89.3°
2047-06-08 Sat	61	—	unknown	00:00–03:40 (good, 3.67 h)	87.2° 05:10	4.58	99%	80.6°
2047-06-09 Sun	57	—	unknown	00:05–03:40 (good, 3.58 h)	87.2° 05:10	4.56	95%	72.4°
2047-06-10 Mon	67	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:05	4.54	90%	65.3°
2047-06-11 Tue	76	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:00	4.52	82%	59.5°
2047-06-12 Wed	85	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:55	4.5	73%	55.5°
2047-06-13 Thu	90	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:50	4.48	64%	53.4°
2047-06-14 Fri	93	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:50	4.47	54%	53.3°
2047-06-15 Sat	96	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:45	4.45	44%	55.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-05-17&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.