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: 06-02 (100), 06-03 (100), 06-04 (100), 06-05 (100), 06-06 (100) — by astronomy; check the weather when the night is within four days.

2043-05-21astronomy score per night — click a bar for that night2043-06-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-05-21 Thu	77	—	unknown	00:30–04:00 (good, 3.5 h)	87.2° 06:25	5.28	96%	108.4°
2043-05-22 Fri	71	—	unknown	00:30–03:55 (good, 3.42 h)	87.3° 06:20	5.23	99%	103.2°
2043-05-23 Sat	67	—	unknown	00:30–03:55 (good, 3.42 h)	87.3° 06:15	5.18	100%	97.5°
2043-05-24 Sun	63	—	unknown	00:25–03:55 (good, 3.5 h)	87.3° 06:10	5.13	99%	91.5°
2043-05-25 Mon	61	—	unknown	00:25–03:55 (good, 3.5 h)	87.2° 06:05	5.09	96%	85.4°
2043-05-26 Tue	60	—	unknown	00:15–03:50 (good, 3.58 h)	87.2° 06:05	5.04	92%	79.4°
2043-05-27 Wed	70	—	unknown	23:45–03:50 (good, 4.08 h)	87.3° 06:00	5.0	86%	73.7°
2043-05-28 Thu	78	—	unknown	23:40–03:50 (good, 4.17 h)	87.3° 05:55	4.96	78%	68.6°
2043-05-29 Fri	87	—	unknown	23:35–03:50 (good, 4.25 h)	87.3° 05:50	4.92	69%	64.3°
2043-05-30 Sat	92	—	unknown	23:35–03:45 (good, 4.17 h)	87.2° 05:45	4.88	59%	61.2°
2043-05-31 Sun	95	—	unknown	23:30–03:45 (good, 4.25 h)	87.3° 05:45	4.84	49%	59.6°
2043-06-01 Mon	98	—	unknown	23:25–03:45 (good, 4.33 h)	87.3° 05:40	4.8	38%	59.8°
2043-06-02 Tue	100	—	unknown	23:20–03:45 (good, 4.42 h)	87.3° 05:35	4.76	27%	62.0°
2043-06-03 Wed	100	—	unknown	23:15–03:45 (good, 4.5 h)	87.2° 05:30	4.73	17%	66.0°
2043-06-04 Thu	100	—	unknown	23:15–03:45 (good, 4.5 h)	87.2° 05:30	4.7	9%	71.7°
2043-06-05 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 05:25	4.67	4%	78.5°
2043-06-06 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:20	4.64	1%	85.9°
2043-06-07 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:15	4.61	0%	93.6°
2043-06-08 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:10	4.58	4%	101.0°
2043-06-09 Tue	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:10	4.56	9%	107.6°
2043-06-10 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:05	4.54	16%	113.2°
2043-06-11 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 05:00	4.52	25%	117.3°
2043-06-12 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:55	4.5	35%	119.8°
2043-06-13 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:50	4.48	45%	120.7°
2043-06-14 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:50	4.47	55%	119.9°
2043-06-15 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:45	4.45	64%	117.7°
2043-06-16 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:40	4.44	73%	114.2°
2043-06-17 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:35	4.43	81%	109.8°
2043-06-18 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:35	4.43	88%	104.7°
2043-06-19 Fri	86	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:30	4.42	93%	99.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-05-21&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.