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: 01-11 (37), 01-10 (36), 01-12 (35), 01-09 (34), 01-13 (34) — by astronomy; check the weather when the night is within four days.

2031-01-05astronomy score per night — click a bar for that night2031-02-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-01-05 Sun	25	—	unknown	18:45–19:30 (good, 0.75 h)	87.3° 14:20	11.4	93%	93.4°
2031-01-06 Mon	26	—	unknown	18:50–20:00 (good, 1.17 h)	87.3° 14:20	11.39	97%	100.6°
2031-01-07 Tue	29	—	unknown	18:50–20:10 (good, 1.33 h)	87.3° 14:15	11.38	99%	107.5°
2031-01-08 Wed	31	—	unknown	18:50–20:10 (good, 1.33 h)	87.3° 14:10	11.36	100%	113.8°
2031-01-09 Thu	34	—	unknown	18:50–20:15 (good, 1.42 h)	87.3° 14:05	11.34	99%	119.4°
2031-01-10 Fri	36	—	unknown	18:50–20:10 (good, 1.33 h)	87.3° 14:00	11.33	96%	123.8°
2031-01-11 Sat	37	—	unknown	18:50–20:15 (good, 1.42 h)	87.3° 14:00	11.31	91%	126.7°
2031-01-12 Sun	35	—	unknown	18:55–20:15 (good, 1.33 h)	87.3° 13:55	11.29	84%	127.7°
2031-01-13 Mon	34	—	unknown	18:55–20:10 (good, 1.25 h)	87.3° 13:50	11.27	76%	126.6°
2031-01-14 Tue	32	—	unknown	18:55–20:05 (good, 1.17 h)	87.3° 13:45	11.25	67%	123.4°
2031-01-15 Wed	30	—	unknown	18:55–20:00 (good, 1.08 h)	87.3° 13:40	11.23	56%	118.4°
2031-01-16 Thu	29	—	unknown	18:55–20:00 (good, 1.08 h)	87.3° 13:40	11.21	46%	111.8°
2031-01-17 Fri	27	—	unknown	19:00–19:55 (good, 0.92 h)	87.3° 13:35	11.19	35%	104.1°
2031-01-18 Sat	26	—	unknown	19:00–19:50 (good, 0.83 h)	87.3° 13:30	11.16	24%	95.6°
2031-01-19 Sun	25	—	unknown	19:00–19:45 (good, 0.75 h)	87.3° 13:25	11.14	15%	86.7°
2031-01-20 Mon	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.3° 13:20	11.11	7%	77.8°
2031-01-21 Tue	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.3° 13:20	11.09	2%	69.3°
2031-01-22 Wed	20	—	unknown	19:05–19:35 (good, 0.5 h)	87.3° 13:15	11.06	0%	61.9°
2031-01-23 Thu	19	—	unknown	19:05–19:30 (good, 0.42 h)	87.3° 13:10	11.03	1%	56.3°
2031-01-24 Fri	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:05	11.01	4%	53.0°
2031-01-25 Sat	15	—	unknown	19:05–19:20 (good, 0.25 h)	87.3° 13:05	10.98	10%	52.5°
2031-01-26 Sun	13	—	unknown	19:05–19:10 (good, 0.08 h)	87.3° 13:00	10.95	18%	54.5°
2031-01-27 Mon	10	—	unknown	19:10–19:50 (marginal, 0.67 h)	87.3° 12:55	10.92	27%	58.5°
2031-01-28 Tue	9	—	unknown	19:10–19:45 (marginal, 0.58 h)	87.3° 12:50	10.89	36%	64.0°
2031-01-29 Wed	7	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.3° 12:45	10.86	46%	70.3°
2031-01-30 Thu	7	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.3° 12:45	10.83	56%	77.2°
2031-01-31 Fri	7	—	unknown	05:45–06:00 (marginal, 0.25 h)	87.3° 12:40	10.8	65%	84.3°
2031-02-01 Sat	8	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:35	10.76	74%	91.6°
2031-02-02 Sun	8	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:30	10.73	82%	98.7°
2031-02-03 Mon	8	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.3° 12:25	10.7	88%	105.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-01-05&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.