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: 12-18 (86), 12-19 (79), 12-20 (71), 12-21 (59), 12-22 (50) — by astronomy; check the weather when the night is within four days.

2047-12-18astronomy score per night — click a bar for that night2048-01-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-12-18 Wed	86	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 15:35	11.5	5%	66.6°
2047-12-19 Thu	79	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:30	11.51	12%	60.1°
2047-12-20 Fri	71	—	unknown	18:35–21:45 (good, 3.17 h)	87.2° 15:25	11.51	20%	55.5°
2047-12-21 Sat	59	—	unknown	18:35–21:30 (good, 2.92 h)	87.2° 15:20	11.51	29%	53.0°
2047-12-22 Sun	50	—	unknown	18:35–21:15 (good, 2.67 h)	87.2° 15:20	11.51	39%	52.8°
2047-12-23 Mon	41	—	unknown	18:40–21:05 (good, 2.42 h)	87.2° 15:15	11.51	48%	54.7°
2047-12-24 Tue	34	—	unknown	18:40–19:45 (good, 1.08 h)	87.2° 15:10	11.5	58%	58.3°
2047-12-25 Wed	29	—	unknown	18:40–18:50 (good, 0.17 h)	87.2° 15:05	11.5	68%	63.1°
2047-12-26 Thu	27	—	unknown	18:40–21:45 (marginal, 3.08 h)	87.2° 15:00	11.5	76%	69.0°
2047-12-27 Fri	27	—	unknown	18:40–21:40 (marginal, 3.0 h)	87.2° 15:00	11.49	84%	75.5°
2047-12-28 Sat	28	—	unknown	18:40–18:55 (good, 0.25 h)	87.2° 14:55	11.49	90%	82.4°
2047-12-29 Sun	30	—	unknown	18:40–19:25 (good, 0.75 h)	87.2° 14:50	11.48	95%	89.6°
2047-12-30 Mon	33	—	unknown	18:40–20:05 (good, 1.42 h)	87.2° 14:45	11.47	98%	96.8°
2047-12-31 Tue	36	—	unknown	18:45–20:30 (good, 1.75 h)	87.2° 14:40	11.46	100%	104.0°
2048-01-01 Wed	41	—	unknown	18:45–20:35 (good, 1.83 h)	87.2° 14:40	11.45	100%	110.8°
2048-01-02 Thu	44	—	unknown	18:45–20:40 (good, 1.92 h)	87.2° 14:35	11.44	97%	116.9°
2048-01-03 Fri	50	—	unknown	18:45–20:40 (good, 1.92 h)	87.2° 14:30	11.43	93%	122.0°
2048-01-04 Sat	50	—	unknown	18:45–20:40 (good, 1.92 h)	87.2° 14:25	11.42	87%	125.6°
2048-01-05 Sun	49	—	unknown	18:45–20:45 (good, 2.0 h)	87.2° 14:25	11.41	79%	127.3°
2048-01-06 Mon	46	—	unknown	18:50–20:40 (good, 1.83 h)	87.2° 14:20	11.39	70%	126.6°
2048-01-07 Tue	44	—	unknown	18:50–20:35 (good, 1.75 h)	87.2° 14:15	11.38	59%	123.7°
2048-01-08 Wed	43	—	unknown	18:50–20:30 (good, 1.67 h)	87.2° 14:10	11.36	48%	118.8°
2048-01-09 Thu	41	—	unknown	18:50–20:25 (good, 1.58 h)	87.2° 14:05	11.35	37%	112.1°
2048-01-10 Fri	39	—	unknown	18:50–20:25 (good, 1.58 h)	87.2° 14:05	11.33	26%	104.3°
2048-01-11 Sat	38	—	unknown	18:50–20:20 (good, 1.5 h)	87.2° 14:00	11.31	17%	95.8°
2048-01-12 Sun	35	—	unknown	18:55–20:15 (good, 1.33 h)	87.2° 13:55	11.29	9%	86.9°
2048-01-13 Mon	34	—	unknown	18:55–20:10 (good, 1.25 h)	87.2° 13:50	11.27	3%	78.1°
2048-01-14 Tue	33	—	unknown	18:55–20:05 (good, 1.17 h)	87.2° 13:45	11.25	0%	69.9°
2048-01-15 Wed	31	—	unknown	18:55–20:05 (good, 1.17 h)	87.2° 13:45	11.23	0%	62.8°
2048-01-16 Thu	30	—	unknown	18:55–20:00 (good, 1.08 h)	87.2° 13:40	11.21	3%	57.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-12-18&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.