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: 07-18 (100), 07-19 (100), 07-20 (100), 07-21 (100), 07-22 (100) — by astronomy; check the weather when the night is within four days.

2041-07-13astronomy score per night — click a bar for that night2041-08-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-07-13 Sat	67	—	unknown	23:00–03:55 (good, 4.92 h)	87.2° 02:50	4.93	100%	72.2°
2041-07-14 Sun	65	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:50	4.97	98%	67.2°
2041-07-15 Mon	68	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:45	5.01	93%	63.6°
2041-07-16 Tue	95	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:40	5.06	86%	61.9°
2041-07-17 Wed	99	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:35	5.1	77%	62.3°
2041-07-18 Thu	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.2° 02:35	5.15	66%	64.5°
2041-07-19 Fri	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:30	5.19	55%	68.2°
2041-07-20 Sat	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:25	5.24	44%	73.0°
2041-07-21 Sun	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:20	5.29	34%	78.6°
2041-07-22 Mon	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:15	5.34	24%	84.5°
2041-07-23 Tue	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:15	5.39	16%	90.5°
2041-07-24 Wed	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.3° 02:10	5.44	9%	96.5°
2041-07-25 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.3° 02:05	5.49	4%	102.0°
2041-07-26 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.3° 02:00	5.54	1%	107.1°
2041-07-27 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:55	5.6	0%	111.4°
2041-07-28 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.3° 01:55	5.65	1%	114.8°
2041-07-29 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.3° 01:50	5.7	3%	117.1°
2041-07-30 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.3° 01:45	5.76	8%	118.2°
2041-07-31 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.3° 01:40	5.81	13%	118.0°
2041-08-01 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:40	5.87	20%	116.5°
2041-08-02 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.3° 01:35	5.92	28%	113.8°
2041-08-03 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.3° 01:30	5.98	38%	110.0°
2041-08-04 Sun	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.3° 01:25	6.03	47%	105.4°
2041-08-05 Mon	100	—	unknown	22:25–04:30 (good, 6.08 h)	87.2° 01:20	6.09	57%	99.9°
2041-08-06 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.3° 01:20	6.15	68%	93.9°
2041-08-07 Wed	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.3° 01:15	6.2	77%	87.5°
2041-08-08 Thu	100	—	unknown	22:20–04:35 (good, 6.25 h)	87.3° 01:10	6.26	86%	81.1°
2041-08-09 Fri	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.3° 01:05	6.32	93%	74.8°
2041-08-10 Sat	70	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:00	6.38	98%	69.2°
2041-08-11 Sun	66	—	unknown	22:15–01:05 (good, 2.83 h)	87.3° 01:00	6.43	100%	64.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-07-13&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.