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: 08-03 (100), 08-04 (100), 08-05 (100), 08-06 (100), 08-07 (100) — by astronomy; check the weather when the night is within four days.

2045-07-28astronomy score per night — click a bar for that night2045-08-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-07-28 Fri	64	—	unknown	22:40–00:45 (good, 2.08 h)	87.2° 01:55	5.65	100%	64.6°
2045-07-29 Sat	60	—	unknown	22:40–23:45 (good, 1.08 h)	87.3° 01:50	5.71	99%	60.3°
2045-07-30 Sun	61	—	unknown	22:35–23:50 (good, 1.25 h)	87.3° 01:45	5.76	96%	57.3°
2045-07-31 Mon	65	—	unknown	22:35–00:15 (good, 1.67 h)	87.2° 01:40	5.81	92%	55.7°
2045-08-01 Tue	70	—	unknown	22:35–01:10 (good, 2.58 h)	87.2° 01:40	5.87	86%	55.9°
2045-08-02 Wed	98	—	unknown	22:30–02:40 (good, 4.17 h)	87.2° 01:35	5.93	79%	57.7°
2045-08-03 Thu	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.3° 01:30	5.98	70%	61.1°
2045-08-04 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:25	6.04	61%	65.8°
2045-08-05 Sat	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:20	6.09	51%	71.7°
2045-08-06 Sun	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:20	6.15	40%	78.5°
2045-08-07 Mon	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.3° 01:15	6.21	30%	86.0°
2045-08-08 Tue	100	—	unknown	22:20–04:35 (good, 6.25 h)	87.3° 01:10	6.26	20%	93.9°
2045-08-09 Wed	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:05	6.32	11%	101.9°
2045-08-10 Thu	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:00	6.38	5%	109.5°
2045-08-11 Fri	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.2° 01:00	6.44	1%	116.2°
2045-08-12 Sat	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.3° 00:55	6.49	0%	121.2°
2045-08-13 Sun	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.3° 00:50	6.55	2%	124.0°
2045-08-14 Mon	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:45	6.61	7%	124.1°
2045-08-15 Tue	100	—	unknown	22:10–04:50 (good, 6.67 h)	87.2° 00:45	6.67	14%	121.8°
2045-08-16 Wed	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:40	6.72	24%	117.4°
2045-08-17 Thu	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.3° 00:35	6.78	34%	111.6°
2045-08-18 Fri	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:30	6.84	44%	105.1°
2045-08-19 Sat	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.9	55%	98.1°
2045-08-20 Sun	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.95	64%	91.1°
2045-08-21 Mon	100	—	unknown	21:55–04:55 (good, 7.0 h)	87.3° 00:20	7.01	74%	84.1°
2045-08-22 Tue	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.3° 00:15	7.07	82%	77.5°
2045-08-23 Wed	98	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:10	7.13	88%	71.3°
2045-08-24 Thu	90	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:05	7.18	94%	65.9°
2045-08-25 Fri	62	—	unknown	02:15–05:05 (good, 2.83 h)	87.2° 00:05	7.24	98%	61.3°
2045-08-26 Sat	60	—	unknown	21:10–05:05 (marginal, 7.92 h)	87.3° 00:00	7.3	100%	57.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-07-28&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.