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: 08-27 (100), 08-28 (100), 08-29 (100), 09-05 (100), 09-06 (100) — by astronomy; check the weather when the night is within four days.

2039-08-27astronomy score per night — click a bar for that night2039-09-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-08-27 Sat	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 00:00	7.32	61%	85.7°
2039-08-28 Sun	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.3° 23:55	7.38	72%	79.3°
2039-08-29 Mon	100	—	unknown	21:40–05:10 (good, 7.5 h)	87.3° 23:50	7.43	82%	73.5°
2039-08-30 Tue	93	—	unknown	21:40–05:10 (good, 7.5 h)	87.3° 23:45	7.49	90%	68.5°
2039-08-31 Wed	85	—	unknown	21:40–05:10 (good, 7.5 h)	87.3° 23:40	7.55	95%	64.9°
2039-09-01 Thu	64	—	unknown	21:35–22:55 (good, 1.33 h)	87.3° 23:40	7.6	99%	62.8°
2039-09-02 Fri	65	—	unknown	21:35–22:55 (good, 1.33 h)	87.3° 23:35	7.66	100%	62.4°
2039-09-03 Sat	69	—	unknown	21:30–23:30 (good, 2.0 h)	87.3° 23:30	7.71	98%	63.7°
2039-09-04 Sun	73	—	unknown	21:30–00:35 (good, 3.08 h)	87.3° 23:25	7.77	95%	66.5°
2039-09-05 Mon	100	—	unknown	21:30–02:15 (good, 4.75 h)	87.3° 23:20	7.82	89%	70.3°
2039-09-06 Tue	100	—	unknown	21:25–03:05 (good, 5.67 h)	87.3° 23:20	7.88	82%	74.9°
2039-09-07 Wed	100	—	unknown	21:25–04:00 (good, 6.58 h)	87.3° 23:15	7.93	74%	80.0°
2039-09-08 Thu	100	—	unknown	21:20–04:55 (good, 7.58 h)	87.3° 23:10	7.99	65%	85.4°
2039-09-09 Fri	100	—	unknown	21:20–05:05 (good, 7.75 h)	87.3° 23:05	8.04	56%	90.9°
2039-09-10 Sat	100	—	unknown	21:20–05:05 (good, 7.75 h)	87.2° 23:00	8.1	47%	96.4°
2039-09-11 Sun	100	—	unknown	21:15–05:10 (good, 7.92 h)	87.3° 23:00	8.15	37%	101.6°
2039-09-12 Mon	100	—	unknown	21:15–05:10 (good, 7.92 h)	87.3° 22:55	8.2	28%	106.5°
2039-09-13 Tue	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.3° 22:50	8.26	20%	110.7°
2039-09-14 Wed	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.3° 22:45	8.31	13%	114.2°
2039-09-15 Thu	100	—	unknown	21:10–05:00 (good, 7.83 h)	87.2° 22:45	8.36	7%	116.6°
2039-09-16 Fri	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.3° 22:40	8.42	3%	117.6°
2039-09-17 Sat	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.3° 22:35	8.47	0%	117.0°
2039-09-18 Sun	100	—	unknown	21:00–04:50 (good, 7.83 h)	87.3° 22:30	8.52	1%	114.8°
2039-09-19 Mon	100	—	unknown	21:00–04:45 (good, 7.75 h)	87.3° 22:25	8.57	3%	111.2°
2039-09-20 Tue	100	—	unknown	21:00–04:45 (good, 7.75 h)	87.3° 22:25	8.62	8%	106.2°
2039-09-21 Wed	100	—	unknown	20:55–04:40 (good, 7.75 h)	87.3° 22:20	8.68	16%	100.4°
2039-09-22 Thu	100	—	unknown	20:55–04:35 (good, 7.67 h)	87.3° 22:15	8.73	25%	94.0°
2039-09-23 Fri	100	—	unknown	20:55–04:30 (good, 7.58 h)	87.3° 22:10	8.78	36%	87.4°
2039-09-24 Sat	100	—	unknown	20:50–04:25 (good, 7.58 h)	87.2° 22:05	8.83	47%	81.0°
2039-09-25 Sun	100	—	unknown	20:50–04:25 (good, 7.58 h)	87.3° 22:05	8.88	58%	75.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-08-27&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.