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: 12-25 (67), 12-26 (67), 12-24 (65), 12-27 (65), 12-28 (63) — by astronomy; check the weather when the night is within four days.

2037-12-20astronomy score per night — click a bar for that night2038-01-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-12-20 Sun	43	—	unknown	18:35–20:15 (good, 1.67 h)	87.3° 15:25	11.51	97%	93.0°
2037-12-21 Mon	46	—	unknown	18:35–20:50 (good, 2.25 h)	87.3° 15:20	11.51	100%	99.1°
2037-12-22 Tue	51	—	unknown	18:35–21:05 (good, 2.5 h)	87.3° 15:15	11.51	100%	105.0°
2037-12-23 Wed	54	—	unknown	18:40–21:10 (good, 2.5 h)	87.3° 15:10	11.5	98%	110.2°
2037-12-24 Thu	65	—	unknown	18:40–21:15 (good, 2.58 h)	87.3° 15:10	11.5	94%	114.5°
2037-12-25 Fri	67	—	unknown	18:40–21:15 (good, 2.58 h)	87.3° 15:05	11.5	87%	117.5°
2037-12-26 Sat	67	—	unknown	18:40–21:20 (good, 2.67 h)	87.3° 15:00	11.49	78%	118.7°
2037-12-27 Sun	65	—	unknown	18:40–21:15 (good, 2.58 h)	87.3° 14:55	11.49	68%	118.1°
2037-12-28 Mon	63	—	unknown	18:40–21:10 (good, 2.5 h)	87.3° 14:50	11.48	57%	115.7°
2037-12-29 Tue	61	—	unknown	18:40–21:10 (good, 2.5 h)	87.3° 14:50	11.48	46%	111.7°
2037-12-30 Wed	59	—	unknown	18:40–21:05 (good, 2.42 h)	87.3° 14:45	11.47	35%	106.4°
2037-12-31 Thu	56	—	unknown	18:45–21:00 (good, 2.25 h)	87.3° 14:40	11.46	24%	100.4°
2038-01-01 Fri	55	—	unknown	18:45–20:55 (good, 2.17 h)	87.3° 14:35	11.45	15%	93.8°
2038-01-02 Sat	53	—	unknown	18:45–20:50 (good, 2.08 h)	87.3° 14:30	11.44	8%	87.1°
2038-01-03 Sun	52	—	unknown	18:45–20:50 (good, 2.08 h)	87.3° 14:30	11.43	3%	80.6°
2038-01-04 Mon	50	—	unknown	18:45–20:45 (good, 2.0 h)	87.3° 14:25	11.41	0%	74.6°
2038-01-05 Tue	47	—	unknown	18:45–20:40 (good, 1.92 h)	87.3° 14:20	11.4	0%	69.5°
2038-01-06 Wed	45	—	unknown	18:50–20:35 (good, 1.75 h)	87.3° 14:15	11.39	2%	65.4°
2038-01-07 Thu	43	—	unknown	18:50–20:35 (good, 1.75 h)	87.3° 14:15	11.37	6%	62.7°
2038-01-08 Fri	39	—	unknown	18:50–20:30 (good, 1.67 h)	87.3° 14:10	11.36	12%	61.4°
2038-01-09 Sat	35	—	unknown	18:50–20:20 (good, 1.5 h)	87.3° 14:05	11.34	18%	61.5°
2038-01-10 Sun	30	—	unknown	18:50–20:10 (good, 1.33 h)	87.3° 14:00	11.32	26%	63.1°
2038-01-11 Mon	26	—	unknown	18:50–20:00 (good, 1.17 h)	87.3° 13:55	11.3	35%	65.8°
2038-01-12 Tue	23	—	unknown	18:55–19:50 (good, 0.92 h)	87.3° 13:55	11.28	44%	69.5°
2038-01-13 Wed	20	—	unknown	18:55–19:40 (good, 0.75 h)	87.3° 13:50	11.27	54%	74.0°
2038-01-14 Thu	18	—	unknown	18:55–19:20 (good, 0.42 h)	87.3° 13:45	11.24	63%	79.1°
2038-01-15 Fri	16	—	unknown	18:55–19:00 (good, 0.08 h)	87.3° 13:40	11.22	72%	84.8°
2038-01-16 Sat	15	—	unknown	18:55–19:00 (good, 0.08 h)	87.3° 13:35	11.2	81%	90.7°
2038-01-17 Sun	15	—	unknown	19:00–19:10 (good, 0.17 h)	87.3° 13:35	11.18	88%	96.8°
2038-01-18 Mon	16	—	unknown	19:00–19:20 (good, 0.33 h)	87.3° 13:30	11.15	94%	102.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-12-20&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.