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: 12-27 (66), 12-28 (61), 12-29 (55), 12-30 (48), 12-31 (40) — by astronomy; check the weather when the night is within four days.

2038-12-27astronomy score per night — click a bar for that night2039-01-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-12-27 Mon	66	—	unknown	18:40–21:15 (good, 2.58 h)	87.3° 14:55	11.49	5%	67.3°
2038-12-28 Tue	61	—	unknown	18:40–21:15 (good, 2.58 h)	87.3° 14:55	11.48	11%	64.1°
2038-12-29 Wed	55	—	unknown	18:40–21:10 (good, 2.5 h)	87.3° 14:50	11.48	18%	62.5°
2038-12-30 Thu	48	—	unknown	18:40–20:55 (good, 2.25 h)	87.3° 14:45	11.47	27%	62.5°
2038-12-31 Fri	40	—	unknown	18:45–20:45 (good, 2.0 h)	87.3° 14:40	11.46	37%	63.9°
2039-01-01 Sat	35	—	unknown	18:45–20:35 (good, 1.83 h)	87.3° 14:35	11.45	46%	66.6°
2039-01-02 Sun	30	—	unknown	18:45–20:20 (good, 1.58 h)	87.3° 14:35	11.44	56%	70.2°
2039-01-03 Mon	27	—	unknown	18:45–19:40 (good, 0.92 h)	87.3° 14:30	11.43	65%	74.6°
2039-01-04 Tue	24	—	unknown	18:45–19:15 (good, 0.5 h)	87.3° 14:25	11.42	74%	79.5°
2039-01-05 Wed	23	—	unknown	18:45–19:10 (good, 0.42 h)	87.3° 14:20	11.4	82%	84.9°
2039-01-06 Thu	22	—	unknown	18:50–19:15 (good, 0.42 h)	87.2° 14:20	11.39	88%	90.4°
2039-01-07 Fri	24	—	unknown	18:50–19:35 (good, 0.75 h)	87.3° 14:15	11.38	94%	95.9°
2039-01-08 Sat	25	—	unknown	18:50–19:55 (good, 1.08 h)	87.3° 14:10	11.36	98%	101.4°
2039-01-09 Sun	27	—	unknown	18:50–20:00 (good, 1.17 h)	87.3° 14:05	11.34	100%	106.4°
2039-01-10 Mon	28	—	unknown	18:50–20:00 (good, 1.17 h)	87.3° 14:00	11.33	100%	110.9°
2039-01-11 Tue	30	—	unknown	18:50–20:05 (good, 1.25 h)	87.3° 14:00	11.31	98%	114.5°
2039-01-12 Wed	33	—	unknown	18:55–20:05 (good, 1.17 h)	87.3° 13:55	11.29	94%	116.9°
2039-01-13 Thu	34	—	unknown	18:55–20:10 (good, 1.25 h)	87.3° 13:50	11.27	88%	117.8°
2039-01-14 Fri	32	—	unknown	18:55–20:05 (good, 1.17 h)	87.3° 13:45	11.25	80%	117.1°
2039-01-15 Sat	30	—	unknown	18:55–20:00 (good, 1.08 h)	87.3° 13:40	11.23	70%	114.7°
2039-01-16 Sun	29	—	unknown	18:55–20:00 (good, 1.08 h)	87.3° 13:40	11.21	59%	111.0°
2039-01-17 Mon	27	—	unknown	19:00–19:55 (good, 0.92 h)	87.3° 13:35	11.18	48%	106.0°
2039-01-18 Tue	26	—	unknown	19:00–19:50 (good, 0.83 h)	87.3° 13:30	11.16	37%	100.1°
2039-01-19 Wed	25	—	unknown	19:00–19:45 (good, 0.75 h)	87.3° 13:25	11.14	26%	93.6°
2039-01-20 Thu	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.2° 13:25	11.11	17%	86.9°
2039-01-21 Fri	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.3° 13:20	11.09	9%	80.4°
2039-01-22 Sat	20	—	unknown	19:05–19:35 (good, 0.5 h)	87.3° 13:15	11.06	4%	74.3°
2039-01-23 Sun	19	—	unknown	19:05–19:30 (good, 0.42 h)	87.3° 13:10	11.03	1%	69.2°
2039-01-24 Mon	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:05	11.01	0%	65.3°
2039-01-25 Tue	16	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:05	10.98	2%	62.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-12-27&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.