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: 12-16 (89), 12-17 (87), 12-18 (85), 12-19 (82), 12-20 (81) — by astronomy; check the weather when the night is within four days.

2041-12-16astronomy score per night — click a bar for that night2042-01-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-12-16 Mon	89	—	unknown	18:35–22:00 (good, 3.42 h)	87.3° 15:40	11.5	37%	115.5°
2041-12-17 Tue	87	—	unknown	18:35–21:55 (good, 3.33 h)	87.3° 15:35	11.5	28%	112.3°
2041-12-18 Wed	85	—	unknown	18:35–21:50 (good, 3.25 h)	87.3° 15:30	11.5	20%	108.0°
2041-12-19 Thu	82	—	unknown	18:35–21:45 (good, 3.17 h)	87.2° 15:25	11.51	13%	102.9°
2041-12-20 Fri	81	—	unknown	18:35–21:45 (good, 3.17 h)	87.3° 15:25	11.51	7%	97.1°
2041-12-21 Sat	78	—	unknown	18:35–21:40 (good, 3.08 h)	87.3° 15:20	11.51	2%	90.9°
2041-12-22 Sun	76	—	unknown	18:35–21:35 (good, 3.0 h)	87.3° 15:15	11.51	0%	84.4°
2041-12-23 Mon	73	—	unknown	18:40–21:30 (good, 2.83 h)	87.3° 15:10	11.51	1%	78.1°
2041-12-24 Tue	71	—	unknown	18:40–21:30 (good, 2.83 h)	87.2° 15:10	11.5	3%	72.2°
2041-12-25 Wed	67	—	unknown	18:40–21:25 (good, 2.75 h)	87.3° 15:05	11.5	9%	67.3°
2041-12-26 Thu	61	—	unknown	18:40–21:20 (good, 2.67 h)	87.3° 15:00	11.49	16%	63.6°
2041-12-27 Fri	53	—	unknown	18:40–21:05 (good, 2.42 h)	87.3° 14:55	11.49	26%	61.7°
2041-12-28 Sat	45	—	unknown	18:40–20:55 (good, 2.25 h)	87.2° 14:50	11.48	36%	61.6°
2041-12-29 Sun	37	—	unknown	18:40–20:40 (good, 2.0 h)	87.2° 14:50	11.48	48%	63.4°
2041-12-30 Mon	31	—	unknown	18:40–20:00 (good, 1.33 h)	87.3° 14:45	11.47	59%	66.9°
2041-12-31 Tue	26	—	unknown	18:45–19:05 (good, 0.33 h)	87.3° 14:40	11.46	70%	71.6°
2042-01-01 Wed	24	—	unknown	18:10–21:20 (marginal, 3.17 h)	87.3° 14:35	11.45	79%	77.3°
2042-01-02 Thu	23	—	unknown	18:45–18:50 (good, 0.08 h)	87.2° 14:30	11.44	87%	83.4°
2042-01-03 Fri	25	—	unknown	18:45–19:10 (good, 0.42 h)	87.3° 14:30	11.43	94%	89.8°
2042-01-04 Sat	26	—	unknown	18:45–19:40 (good, 0.92 h)	87.3° 14:25	11.41	98%	96.1°
2042-01-05 Sun	29	—	unknown	18:45–20:10 (good, 1.42 h)	87.3° 14:20	11.4	100%	102.1°
2042-01-06 Mon	31	—	unknown	18:50–20:15 (good, 1.42 h)	87.3° 14:15	11.39	100%	107.4°
2042-01-07 Tue	34	—	unknown	18:50–20:15 (good, 1.42 h)	87.2° 14:15	11.37	97%	112.0°
2042-01-08 Wed	39	—	unknown	18:50–20:15 (good, 1.42 h)	87.3° 14:10	11.36	93%	115.4°
2042-01-09 Thu	40	—	unknown	18:50–20:20 (good, 1.5 h)	87.3° 14:05	11.34	88%	117.7°
2042-01-10 Fri	38	—	unknown	18:50–20:20 (good, 1.5 h)	87.3° 14:00	11.32	81%	118.7°
2042-01-11 Sat	37	—	unknown	18:50–20:15 (good, 1.42 h)	87.2° 13:55	11.3	73%	118.3°
2042-01-12 Sun	35	—	unknown	18:55–20:15 (good, 1.33 h)	87.2° 13:55	11.28	64%	116.6°
2042-01-13 Mon	34	—	unknown	18:55–20:10 (good, 1.25 h)	87.3° 13:50	11.26	55%	113.7°
2042-01-14 Tue	32	—	unknown	18:55–20:05 (good, 1.17 h)	87.3° 13:45	11.24	46%	109.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-12-16&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.