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: 09-22 (100), 09-23 (100), 09-24 (100), 09-25 (100), 09-26 (100) — by astronomy; check the weather when the night is within four days.

2041-09-22astronomy score per night — click a bar for that night2041-10-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-09-22 Sun	100	—	unknown	20:55–04:35 (good, 7.67 h)	87.3° 22:15	8.75	5%	117.8°
2041-09-23 Mon	100	—	unknown	20:50–04:30 (good, 7.67 h)	87.3° 22:10	8.8	2%	118.3°
2041-09-24 Tue	100	—	unknown	20:50–04:25 (good, 7.58 h)	87.3° 22:05	8.85	0%	117.6°
2041-09-25 Wed	100	—	unknown	20:50–04:20 (good, 7.5 h)	87.3° 22:00	8.9	0%	115.5°
2041-09-26 Thu	100	—	unknown	20:45–04:20 (good, 7.58 h)	87.2° 22:00	8.95	2%	112.4°
2041-09-27 Fri	100	—	unknown	20:45–04:15 (good, 7.5 h)	87.3° 21:55	9.0	6%	108.2°
2041-09-28 Sat	100	—	unknown	20:45–04:10 (good, 7.42 h)	87.3° 21:50	9.05	12%	103.2°
2041-09-29 Sun	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.3° 21:45	9.1	19%	97.7°
2041-09-30 Mon	100	—	unknown	20:40–04:00 (good, 7.33 h)	87.2° 21:40	9.15	27%	91.7°
2041-10-01 Tue	100	—	unknown	20:35–04:00 (good, 7.42 h)	87.2° 21:40	9.2	37%	85.5°
2041-10-02 Wed	100	—	unknown	20:35–03:55 (good, 7.33 h)	87.3° 21:35	9.24	48%	79.4°
2041-10-03 Thu	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.3° 21:30	9.29	59%	73.7°
2041-10-04 Fri	91	—	unknown	20:30–03:45 (good, 7.25 h)	87.3° 21:25	9.34	70%	68.6°
2041-10-05 Sat	82	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.39	80%	64.6°
2041-10-06 Sun	64	—	unknown	20:30–00:55 (good, 4.42 h)	87.3° 21:20	9.43	88%	62.2°
2041-10-07 Mon	62	—	unknown	20:25–21:05 (good, 0.67 h)	87.3° 21:15	9.48	95%	61.8°
2041-10-08 Tue	63	—	unknown	20:25–21:05 (good, 0.67 h)	87.3° 21:10	9.53	99%	63.5°
2041-10-09 Wed	66	—	unknown	20:25–21:40 (good, 1.25 h)	87.3° 21:05	9.57	100%	67.0°
2041-10-10 Thu	71	—	unknown	20:20–23:00 (good, 2.67 h)	87.2° 21:05	9.62	98%	72.1°
2041-10-11 Fri	77	—	unknown	20:20–00:20 (good, 4.0 h)	87.3° 21:00	9.66	94%	78.0°
2041-10-12 Sat	100	—	unknown	20:20–01:20 (good, 5.0 h)	87.3° 20:55	9.71	87%	84.3°
2041-10-13 Sun	100	—	unknown	20:15–02:25 (good, 6.17 h)	87.3° 20:50	9.75	78%	90.7°
2041-10-14 Mon	100	—	unknown	20:15–02:40 (good, 6.42 h)	87.3° 20:45	9.79	69%	96.9°
2041-10-15 Tue	100	—	unknown	20:15–02:45 (good, 6.5 h)	87.2° 20:45	9.84	60%	102.6°
2041-10-16 Wed	100	—	unknown	20:15–02:50 (good, 6.58 h)	87.3° 20:40	9.88	50%	107.6°
2041-10-17 Thu	100	—	unknown	20:10–02:50 (good, 6.67 h)	87.3° 20:35	9.92	40%	111.9°
2041-10-18 Fri	100	—	unknown	20:10–02:45 (good, 6.58 h)	87.3° 20:30	9.97	31%	115.2°
2041-10-19 Sat	100	—	unknown	20:10–02:45 (good, 6.58 h)	87.2° 20:25	10.01	22%	117.3°
2041-10-20 Sun	100	—	unknown	20:05–02:45 (good, 6.67 h)	87.3° 20:25	10.05	15%	118.3°
2041-10-21 Mon	100	—	unknown	20:05–02:40 (good, 6.58 h)	87.3° 20:20	10.09	9%	117.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-09-22&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.