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: 08-19 (100), 08-20 (100), 08-21 (100), 08-22 (100), 08-23 (100) — by astronomy; check the weather when the night is within four days.

2028-08-19astronomy score per night — click a bar for that night2028-09-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-08-19 Sat	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.3° 00:25	6.9	0%	122.9°
2028-08-20 Sun	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.3° 00:20	6.96	0%	126.0°
2028-08-21 Mon	100	—	unknown	21:55–04:55 (good, 7.0 h)	87.3° 00:20	7.02	4%	126.2°
2028-08-22 Tue	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.3° 00:15	7.07	9%	123.6°
2028-08-23 Wed	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.3° 00:10	7.13	17%	118.7°
2028-08-24 Thu	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.3° 00:05	7.19	27%	112.2°
2028-08-25 Fri	100	—	unknown	21:50–05:05 (good, 7.25 h)	87.3° 00:00	7.25	38%	104.8°
2028-08-26 Sat	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.3° 00:00	7.3	49%	97.0°
2028-08-27 Sun	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.3° 23:55	7.36	59%	89.2°
2028-08-28 Mon	100	—	unknown	21:40–05:05 (good, 7.42 h)	87.3° 23:50	7.42	69%	81.6°
2028-08-29 Tue	100	—	unknown	21:40–05:10 (good, 7.5 h)	87.3° 23:45	7.47	78%	74.5°
2028-08-30 Wed	96	—	unknown	21:40–05:10 (good, 7.5 h)	87.3° 23:45	7.53	86%	68.0°
2028-08-31 Thu	88	—	unknown	21:35–05:10 (good, 7.58 h)	87.3° 23:40	7.58	92%	62.4°
2028-09-01 Fri	81	—	unknown	05:10–05:15 (good, 0.08 h)	87.3° 23:35	7.64	96%	57.9°
2028-09-02 Sat	57	—	unknown	21:30–05:15 (marginal, 7.75 h)	87.3° 23:30	7.7	99%	54.9°
2028-09-03 Sun	57	—	unknown	21:30–05:15 (marginal, 7.75 h)	87.3° 23:25	7.75	100%	53.6°
2028-09-04 Mon	59	—	unknown	21:30–05:15 (marginal, 7.75 h)	87.3° 23:25	7.81	99%	54.0°
2028-09-05 Tue	63	—	unknown	21:25–22:00 (good, 0.58 h)	87.3° 23:20	7.86	96%	56.3°
2028-09-06 Wed	68	—	unknown	21:25–23:10 (good, 1.75 h)	87.3° 23:15	7.92	92%	60.0°
2028-09-07 Thu	74	—	unknown	21:20–00:55 (good, 3.58 h)	87.3° 23:10	7.97	86%	65.0°
2028-09-08 Fri	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.3° 23:05	8.03	79%	71.0°
2028-09-09 Sat	100	—	unknown	21:20–03:50 (good, 6.5 h)	87.3° 23:05	8.08	71%	77.7°
2028-09-10 Sun	100	—	unknown	21:15–04:50 (good, 7.58 h)	87.3° 23:00	8.13	61%	84.9°
2028-09-11 Mon	100	—	unknown	21:15–04:55 (good, 7.67 h)	87.3° 22:55	8.19	51%	92.5°
2028-09-12 Tue	100	—	unknown	21:15–05:00 (good, 7.75 h)	87.3° 22:50	8.24	41%	100.2°
2028-09-13 Wed	100	—	unknown	21:10–05:00 (good, 7.83 h)	87.3° 22:50	8.29	30%	107.8°
2028-09-14 Thu	100	—	unknown	21:10–05:00 (good, 7.83 h)	87.3° 22:45	8.35	20%	114.9°
2028-09-15 Fri	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.3° 22:40	8.4	12%	120.8°
2028-09-16 Sat	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.3° 22:35	8.45	5%	124.9°
2028-09-17 Sun	100	—	unknown	21:05–04:50 (good, 7.75 h)	87.3° 22:30	8.5	1%	126.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-08-19&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.