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: 05-17 (100), 05-18 (100), 05-19 (100), 05-20 (100), 05-21 (100) — by astronomy; check the weather when the night is within four days.

2042-04-25astronomy score per night — click a bar for that night2042-05-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-04-25 Fri	72	—	unknown	01:55–04:40 (good, 2.75 h)	87.3° 08:05	6.71	38%	106.7°
2042-04-26 Sat	73	—	unknown	01:50–04:40 (good, 2.83 h)	87.3° 08:00	6.65	48%	111.4°
2042-04-27 Sun	74	—	unknown	01:50–04:40 (good, 2.83 h)	87.3° 07:55	6.59	58%	115.1°
2042-04-28 Mon	73	—	unknown	01:45–04:35 (good, 2.83 h)	87.2° 07:50	6.53	68%	117.6°
2042-04-29 Tue	73	—	unknown	01:45–04:35 (good, 2.83 h)	87.3° 07:50	6.47	76%	118.8°
2042-04-30 Wed	68	—	unknown	01:40–04:35 (good, 2.92 h)	87.3° 07:45	6.41	84%	118.6°
2042-05-01 Thu	66	—	unknown	01:40–04:30 (good, 2.83 h)	87.3° 07:40	6.36	90%	117.2°
2042-05-02 Fri	64	—	unknown	01:40–04:30 (good, 2.83 h)	87.3° 07:35	6.3	95%	114.5°
2042-05-03 Sat	60	—	unknown	01:40–04:25 (good, 2.75 h)	87.2° 07:35	6.24	98%	110.7°
2042-05-04 Sun	57	—	unknown	01:40–04:25 (good, 2.75 h)	87.3° 07:30	6.18	100%	106.1°
2042-05-05 Mon	55	—	unknown	01:35–04:25 (good, 2.83 h)	87.3° 07:25	6.13	100%	100.8°
2042-05-06 Tue	52	—	unknown	01:35–04:20 (good, 2.75 h)	87.3° 07:20	6.07	97%	95.1°
2042-05-07 Wed	51	—	unknown	01:30–04:20 (good, 2.83 h)	87.2° 07:15	6.01	93%	89.0°
2042-05-08 Thu	52	—	unknown	01:25–04:20 (good, 2.92 h)	87.2° 07:15	5.96	87%	82.9°
2042-05-09 Fri	55	—	unknown	01:15–04:15 (good, 3.0 h)	87.3° 07:10	5.9	79%	77.0°
2042-05-10 Sat	66	—	unknown	00:50–04:15 (good, 3.42 h)	87.3° 07:05	5.84	70%	71.6°
2042-05-11 Sun	74	—	unknown	00:45–04:15 (good, 3.5 h)	87.3° 07:00	5.79	60%	66.9°
2042-05-12 Mon	81	—	unknown	00:40–04:10 (good, 3.5 h)	87.2° 06:55	5.73	49%	63.4°
2042-05-13 Tue	88	—	unknown	00:40–04:10 (good, 3.5 h)	87.3° 06:55	5.68	37%	61.4°
2042-05-14 Wed	94	—	unknown	00:35–04:10 (good, 3.58 h)	87.3° 06:50	5.62	27%	61.3°
2042-05-15 Thu	96	—	unknown	00:30–04:05 (good, 3.58 h)	87.3° 06:45	5.57	17%	63.1°
2042-05-16 Fri	99	—	unknown	00:25–04:05 (good, 3.67 h)	87.3° 06:40	5.52	9%	66.9°
2042-05-17 Sat	100	—	unknown	00:25–04:05 (good, 3.67 h)	87.2° 06:40	5.47	3%	72.1°
2042-05-18 Sun	100	—	unknown	00:20–04:00 (good, 3.67 h)	87.3° 06:35	5.41	0%	78.3°
2042-05-19 Mon	100	—	unknown	00:15–04:00 (good, 3.75 h)	87.3° 06:30	5.36	0%	85.1°
2042-05-20 Tue	100	—	unknown	00:10–04:00 (good, 3.83 h)	87.3° 06:25	5.31	3%	92.0°
2042-05-21 Wed	100	—	unknown	00:05–04:00 (good, 3.92 h)	87.2° 06:20	5.26	8%	98.6°
2042-05-22 Thu	100	—	unknown	00:05–03:55 (good, 3.83 h)	87.2° 06:20	5.22	15%	104.7°
2042-05-23 Fri	100	—	unknown	00:00–03:55 (good, 3.92 h)	87.3° 06:15	5.17	23%	109.9°
2042-05-24 Sat	100	—	unknown	00:00–03:55 (good, 3.92 h)	87.3° 06:10	5.12	32%	114.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-04-25&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.