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: 10-27 (100), 10-28 (100), 10-29 (100), 10-30 (100), 10-31 (100) — by astronomy; check the weather when the night is within four days.

2040-10-27astronomy score per night — click a bar for that night2040-11-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-10-27 Sat	100	—	unknown	19:55–02:05 (good, 6.17 h)	87.3° 19:55	10.34	51%	111.4°
2040-10-28 Sun	100	—	unknown	18:55–01:05 (good, 6.17 h)	87.3° 18:50	10.38	42%	114.5°
2040-10-29 Mon	100	—	unknown	18:55–01:05 (good, 6.17 h)	87.3° 18:45	10.41	32%	116.6°
2040-10-30 Tue	100	—	unknown	18:55–01:05 (good, 6.17 h)	87.2° 18:45	10.45	24%	117.5°
2040-10-31 Wed	100	—	unknown	18:55–01:00 (good, 6.08 h)	87.3° 18:40	10.49	16%	117.0°
2040-11-01 Thu	100	—	unknown	18:50–00:55 (good, 6.08 h)	87.3° 18:35	10.52	9%	115.2°
2040-11-02 Fri	100	—	unknown	18:50–00:50 (good, 6.0 h)	87.3° 18:30	10.56	4%	112.0°
2040-11-03 Sat	100	—	unknown	18:50–00:45 (good, 5.92 h)	87.2° 18:25	10.59	1%	107.6°
2040-11-04 Sun	100	—	unknown	18:50–00:45 (good, 5.92 h)	87.3° 18:25	10.63	0%	102.2°
2040-11-05 Mon	100	—	unknown	18:45–00:40 (good, 5.92 h)	87.3° 18:20	10.66	2%	96.1°
2040-11-06 Tue	100	—	unknown	18:45–00:35 (good, 5.83 h)	87.3° 18:15	10.7	6%	89.6°
2040-11-07 Wed	100	—	unknown	18:45–00:30 (good, 5.75 h)	87.3° 18:10	10.73	12%	83.1°
2040-11-08 Thu	100	—	unknown	18:45–00:25 (good, 5.67 h)	87.2° 18:10	10.76	21%	77.0°
2040-11-09 Fri	99	—	unknown	18:45–00:25 (good, 5.67 h)	87.3° 18:05	10.8	31%	71.5°
2040-11-10 Sat	90	—	unknown	18:45–00:20 (good, 5.58 h)	87.3° 18:00	10.83	42%	67.0°
2040-11-11 Sun	81	—	unknown	18:40–00:15 (good, 5.58 h)	87.3° 17:55	10.86	53%	64.0°
2040-11-12 Mon	72	—	unknown	18:40–23:45 (good, 5.08 h)	87.3° 17:50	10.89	64%	62.6°
2040-11-13 Tue	64	—	unknown	18:40–22:05 (good, 3.42 h)	87.2° 17:50	10.92	75%	62.9°
2040-11-14 Wed	56	—	unknown	18:40–20:40 (good, 2.0 h)	87.3° 17:45	10.95	84%	65.0°
2040-11-15 Thu	52	—	unknown	18:40–19:45 (good, 1.08 h)	87.3° 17:40	10.98	91%	68.4°
2040-11-16 Fri	52	—	unknown	18:40–20:00 (good, 1.33 h)	87.3° 17:35	11.0	96%	72.9°
2040-11-17 Sat	56	—	unknown	18:40–20:35 (good, 1.92 h)	87.2° 17:30	11.03	99%	78.2°
2040-11-18 Sun	64	—	unknown	18:35–21:10 (good, 2.58 h)	87.3° 17:30	11.06	100%	83.9°
2040-11-19 Mon	73	—	unknown	18:35–21:55 (good, 3.33 h)	87.3° 17:25	11.08	99%	89.8°
2040-11-20 Tue	83	—	unknown	18:35–22:40 (good, 4.08 h)	87.3° 17:20	11.11	95%	95.5°
2040-11-21 Wed	100	—	unknown	18:35–23:05 (good, 4.5 h)	87.3° 17:15	11.13	90%	100.9°
2040-11-22 Thu	100	—	unknown	18:35–23:10 (good, 4.58 h)	87.2° 17:15	11.16	84%	105.9°
2040-11-23 Fri	100	—	unknown	18:35–23:15 (good, 4.67 h)	87.3° 17:10	11.18	76%	110.1°
2040-11-24 Sat	100	—	unknown	18:35–23:15 (good, 4.67 h)	87.3° 17:05	11.2	68%	113.6°
2040-11-25 Sun	100	—	unknown	18:35–23:15 (good, 4.67 h)	87.3° 17:00	11.23	59%	116.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-10-27&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.