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: 01-02 (52), 01-03 (52), 12-21 (51), 01-01 (50), 01-04 (50) — by astronomy; check the weather when the night is within four days.

2039-12-21astronomy score per night — click a bar for that night2040-01-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-12-21 Wed	51	—	unknown	18:35–21:20 (good, 2.75 h)	87.3° 15:20	11.51	45%	63.7°
2039-12-22 Thu	43	—	unknown	18:35–21:05 (good, 2.5 h)	87.2° 15:20	11.51	55%	66.1°
2039-12-23 Fri	37	—	unknown	18:40–20:10 (good, 1.5 h)	87.3° 15:15	11.51	65%	69.7°
2039-12-24 Sat	33	—	unknown	18:40–19:30 (good, 0.83 h)	87.3° 15:10	11.5	74%	74.0°
2039-12-25 Sun	31	—	unknown	18:40–19:15 (good, 0.58 h)	87.3° 15:05	11.5	82%	78.9°
2039-12-26 Mon	31	—	unknown	18:40–19:20 (good, 0.67 h)	87.3° 15:00	11.5	89%	84.2°
2039-12-27 Tue	32	—	unknown	18:40–19:35 (good, 0.92 h)	87.2° 15:00	11.49	94%	89.6°
2039-12-28 Wed	35	—	unknown	18:40–20:00 (good, 1.33 h)	87.3° 14:55	11.49	98%	95.1°
2039-12-29 Thu	38	—	unknown	18:40–20:30 (good, 1.83 h)	87.3° 14:50	11.48	100%	100.3°
2039-12-30 Fri	40	—	unknown	18:40–20:40 (good, 2.0 h)	87.3° 14:45	11.47	100%	105.2°
2039-12-31 Sat	42	—	unknown	18:45–20:40 (good, 1.92 h)	87.3° 14:40	11.46	98%	109.5°
2040-01-01 Sun	50	—	unknown	18:45–20:45 (good, 2.0 h)	87.3° 14:40	11.45	95%	113.1°
2040-01-02 Mon	52	—	unknown	18:45–20:45 (good, 2.0 h)	87.3° 14:35	11.44	90%	115.7°
2040-01-03 Tue	52	—	unknown	18:45–20:50 (good, 2.08 h)	87.3° 14:30	11.43	83%	117.1°
2040-01-04 Wed	50	—	unknown	18:45–20:45 (good, 2.0 h)	87.3° 14:25	11.42	75%	117.2°
2040-01-05 Thu	48	—	unknown	18:45–20:40 (good, 1.92 h)	87.2° 14:20	11.41	66%	115.9°
2040-01-06 Fri	47	—	unknown	18:45–20:40 (good, 1.92 h)	87.3° 14:20	11.39	56%	113.3°
2040-01-07 Sat	44	—	unknown	18:50–20:35 (good, 1.75 h)	87.3° 14:15	11.38	45%	109.3°
2040-01-08 Sun	43	—	unknown	18:50–20:30 (good, 1.67 h)	87.3° 14:10	11.36	34%	104.2°
2040-01-09 Mon	41	—	unknown	18:50–20:25 (good, 1.58 h)	87.3° 14:05	11.35	24%	98.2°
2040-01-10 Tue	40	—	unknown	18:50–20:25 (good, 1.58 h)	87.2° 14:05	11.33	15%	91.7°
2040-01-11 Wed	38	—	unknown	18:50–20:20 (good, 1.5 h)	87.3° 14:00	11.31	7%	84.8°
2040-01-12 Thu	35	—	unknown	18:55–20:15 (good, 1.33 h)	87.3° 13:55	11.29	2%	78.2°
2040-01-13 Fri	34	—	unknown	18:55–20:10 (good, 1.25 h)	87.3° 13:50	11.27	0%	72.2°
2040-01-14 Sat	33	—	unknown	18:55–20:05 (good, 1.17 h)	87.3° 13:45	11.25	1%	67.4°
2040-01-15 Sun	31	—	unknown	18:55–20:05 (good, 1.17 h)	87.3° 13:45	11.23	5%	64.1°
2040-01-16 Mon	28	—	unknown	18:55–19:55 (good, 1.0 h)	87.3° 13:40	11.21	11%	62.6°
2040-01-17 Tue	24	—	unknown	19:00–19:50 (good, 0.83 h)	87.3° 13:35	11.19	19%	63.0°
2040-01-18 Wed	20	—	unknown	19:00–19:40 (good, 0.67 h)	87.3° 13:30	11.17	28%	65.1°
2040-01-19 Thu	17	—	unknown	19:00–19:25 (good, 0.42 h)	87.2° 13:25	11.14	38%	68.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-12-21&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.