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: 07-27 (100), 07-28 (100), 07-29 (100), 07-30 (100), 07-31 (100) — by astronomy; check the weather when the night is within four days.

2040-07-27astronomy score per night — click a bar for that night2040-08-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-07-27 Fri	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.3° 01:55	5.61	80%	63.9°
2040-07-28 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:55	5.66	70%	66.9°
2040-07-29 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.3° 01:50	5.72	60%	71.0°
2040-07-30 Mon	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.3° 01:45	5.77	49%	75.9°
2040-07-31 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.3° 01:40	5.83	39%	81.2°
2040-08-01 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.3° 01:35	5.88	30%	86.8°
2040-08-02 Thu	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:35	5.94	22%	92.4°
2040-08-03 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.3° 01:30	5.99	14%	97.8°
2040-08-04 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.3° 01:25	6.05	8%	102.9°
2040-08-05 Sun	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.3° 01:20	6.1	4%	107.6°
2040-08-06 Mon	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:15	6.16	1%	111.6°
2040-08-07 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.3° 01:15	6.22	0%	114.7°
2040-08-08 Wed	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.3° 01:10	6.28	1%	116.8°
2040-08-09 Thu	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.3° 01:05	6.33	4%	117.6°
2040-08-10 Fri	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.3° 01:00	6.39	8%	117.2°
2040-08-11 Sat	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.2° 00:55	6.45	14%	115.3°
2040-08-12 Sun	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.3° 00:55	6.5	22%	112.2°
2040-08-13 Mon	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.3° 00:50	6.56	31%	108.0°
2040-08-14 Tue	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.3° 00:45	6.62	41%	102.9°
2040-08-15 Wed	100	—	unknown	22:10–04:50 (good, 6.67 h)	87.3° 00:40	6.68	52%	97.0°
2040-08-16 Thu	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:40	6.73	63%	90.7°
2040-08-17 Fri	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.3° 00:35	6.79	73%	84.2°
2040-08-18 Sat	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.3° 00:30	6.85	83%	77.8°
2040-08-19 Sun	98	—	unknown	22:00–04:55 (good, 6.92 h)	87.3° 00:25	6.91	91%	71.9°
2040-08-20 Mon	88	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:20	6.96	97%	67.1°
2040-08-21 Tue	65	—	unknown	21:55–23:45 (good, 1.83 h)	87.3° 00:20	7.02	100%	63.8°
2040-08-22 Wed	66	—	unknown	21:55–23:30 (good, 1.58 h)	87.3° 00:15	7.08	99%	62.4°
2040-08-23 Thu	70	—	unknown	21:50–00:10 (good, 2.33 h)	87.3° 00:10	7.14	96%	63.0°
2040-08-24 Fri	74	—	unknown	21:50–01:25 (good, 3.58 h)	87.3° 00:05	7.19	91%	65.3°
2040-08-25 Sat	100	—	unknown	21:50–03:10 (good, 5.33 h)	87.2° 00:00	7.25	84%	69.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-07-27&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.