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: 05-24 (100), 05-25 (100), 05-26 (100), 05-27 (100), 05-28 (100) — by astronomy; check the weather when the night is within four days.

2041-05-07astronomy score per night — click a bar for that night2041-06-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-05-07 Tue	85	—	unknown	01:10–04:20 (good, 3.17 h)	87.3° 07:15	6.0	48%	114.3°
2041-05-08 Wed	86	—	unknown	01:05–04:20 (good, 3.25 h)	87.2° 07:10	5.94	57%	116.6°
2041-05-09 Thu	85	—	unknown	01:05–04:15 (good, 3.17 h)	87.2° 07:10	5.89	66%	117.7°
2041-05-10 Fri	85	—	unknown	01:00–04:15 (good, 3.25 h)	87.3° 07:05	5.83	75%	117.6°
2041-05-11 Sat	77	—	unknown	01:00–04:15 (good, 3.25 h)	87.3° 07:00	5.77	83%	116.1°
2041-05-12 Sun	74	—	unknown	01:00–04:10 (good, 3.17 h)	87.3° 06:55	5.72	90%	113.4°
2041-05-13 Mon	71	—	unknown	01:00–04:10 (good, 3.17 h)	87.2° 06:50	5.67	95%	109.4°
2041-05-14 Tue	66	—	unknown	01:00–04:10 (good, 3.17 h)	87.3° 06:50	5.61	99%	104.5°
2041-05-15 Wed	61	—	unknown	01:00–04:05 (good, 3.08 h)	87.3° 06:45	5.56	100%	98.9°
2041-05-16 Thu	58	—	unknown	00:55–04:05 (good, 3.17 h)	87.3° 06:40	5.51	99%	92.7°
2041-05-17 Fri	56	—	unknown	00:55–04:05 (good, 3.17 h)	87.3° 06:35	5.45	96%	86.3°
2041-05-18 Sat	55	—	unknown	00:45–04:00 (good, 3.25 h)	87.2° 06:35	5.4	90%	79.9°
2041-05-19 Sun	65	—	unknown	00:15–04:00 (good, 3.75 h)	87.3° 06:30	5.35	82%	74.0°
2041-05-20 Mon	76	—	unknown	00:10–04:00 (good, 3.83 h)	87.3° 06:25	5.3	72%	69.0°
2041-05-21 Tue	85	—	unknown	00:05–04:00 (good, 3.92 h)	87.3° 06:20	5.25	62%	65.1°
2041-05-22 Wed	94	—	unknown	00:00–03:55 (good, 3.92 h)	87.2° 06:15	5.2	50%	62.7°
2041-05-23 Thu	98	—	unknown	00:00–03:55 (good, 3.92 h)	87.2° 06:15	5.16	39%	62.2°
2041-05-24 Fri	100	—	unknown	23:55–03:55 (good, 4.0 h)	87.3° 06:10	5.11	28%	63.4°
2041-05-25 Sat	100	—	unknown	23:50–03:50 (good, 4.0 h)	87.3° 06:05	5.07	18%	66.4°
2041-05-26 Sun	100	—	unknown	23:45–03:50 (good, 4.08 h)	87.3° 06:00	5.02	10%	70.6°
2041-05-27 Mon	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:55	4.98	5%	75.9°
2041-05-28 Tue	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.3° 05:55	4.94	1%	81.7°
2041-05-29 Wed	100	—	unknown	23:35–03:50 (good, 4.25 h)	87.3° 05:50	4.9	0%	87.8°
2041-05-30 Thu	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.3° 05:45	4.86	1%	93.9°
2041-05-31 Fri	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.3° 05:40	4.82	4%	99.7°
2041-06-01 Sat	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.2° 05:40	4.78	9%	105.0°
2041-06-02 Sun	100	—	unknown	23:20–03:45 (good, 4.42 h)	87.3° 05:35	4.75	16%	109.6°
2041-06-03 Mon	100	—	unknown	23:20–03:45 (good, 4.42 h)	87.3° 05:30	4.71	23%	113.3°
2041-06-04 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 05:25	4.68	32%	116.0°
2041-06-05 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 05:20	4.65	41%	117.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-05-07&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.