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: 06-23 (100), 06-24 (100), 06-25 (100), 07-07 (100), 07-08 (100) — by astronomy; check the weather when the night is within four days.

2045-06-23astronomy score per night — click a bar for that night2045-07-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-06-23 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:10	4.43	73%	114.2°
2045-06-24 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:05	4.44	82%	108.1°
2045-06-25 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 04:05	4.45	89%	101.5°
2045-06-26 Mon	84	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:00	4.46	94%	94.5°
2045-06-27 Tue	79	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 03:55	4.47	98%	87.5°
2045-06-28 Wed	71	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 03:50	4.49	100%	80.7°
2045-06-29 Thu	63	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:50	4.51	100%	74.3°
2045-06-30 Fri	59	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:45	4.53	98%	68.4°
2045-07-01 Sat	59	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:40	4.55	94%	63.4°
2045-07-02 Sun	61	—	unknown	23:10–03:25 (good, 4.25 h)	87.3° 03:35	4.57	88%	59.4°
2045-07-03 Mon	87	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:30	4.59	82%	56.8°
2045-07-04 Tue	93	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:30	4.62	74%	55.7°
2045-07-05 Wed	96	—	unknown	23:10–03:50 (good, 4.67 h)	87.2° 03:25	4.65	65%	56.3°
2045-07-06 Thu	99	—	unknown	23:10–03:50 (good, 4.67 h)	87.3° 03:20	4.68	55%	58.6°
2045-07-07 Fri	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.2° 03:15	4.71	45%	62.4°
2045-07-08 Sat	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.2° 03:10	4.74	35%	67.6°
2045-07-09 Sun	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.2° 03:10	4.78	26%	74.0°
2045-07-10 Mon	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.3° 03:05	4.81	17%	81.3°
2045-07-11 Tue	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.3° 03:00	4.85	9%	89.1°
2045-07-12 Wed	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.2° 02:55	4.89	3%	97.3°
2045-07-13 Thu	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:55	4.93	0%	105.3°
2045-07-14 Fri	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:50	4.97	0%	112.6°
2045-07-15 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:45	5.02	3%	118.7°
2045-07-16 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:40	5.06	9%	122.7°
2045-07-17 Mon	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.2° 02:35	5.1	17%	124.4°
2045-07-18 Tue	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.2° 02:35	5.15	27%	123.5°
2045-07-19 Wed	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.2° 02:30	5.2	38%	120.4°
2045-07-20 Thu	100	—	unknown	22:55–04:10 (good, 5.25 h)	87.3° 02:25	5.24	48%	115.6°
2045-07-21 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:20	5.29	59%	109.7°
2045-07-22 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:15	5.34	69%	103.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-06-23&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.