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: 05-01 (81), 04-29 (79), 04-30 (79), 04-27 (78), 04-28 (78) — by astronomy; check the weather when the night is within four days.

2041-04-02astronomy score per night — click a bar for that night2041-05-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-04-02 Tue	53	—	unknown	03:20–05:25 (good, 2.08 h)	87.3° 09:35	8.01	5%	74.5°
2041-04-03 Wed	54	—	unknown	03:15–05:25 (good, 2.17 h)	87.3° 09:30	7.95	10%	80.3°
2041-04-04 Thu	56	—	unknown	03:10–05:25 (good, 2.25 h)	87.3° 09:25	7.9	18%	86.4°
2041-04-05 Fri	56	—	unknown	03:05–05:20 (good, 2.25 h)	87.3° 09:20	7.84	26%	92.4°
2041-04-06 Sat	57	—	unknown	03:05–05:20 (good, 2.25 h)	87.2° 09:20	7.78	36%	98.2°
2041-04-07 Sun	56	—	unknown	03:00–05:15 (good, 2.25 h)	87.3° 09:15	7.73	46%	103.5°
2041-04-08 Mon	57	—	unknown	03:05–05:15 (good, 2.17 h)	87.3° 09:10	7.67	55%	108.2°
2041-04-09 Tue	58	—	unknown	03:00–05:15 (good, 2.25 h)	87.3° 09:05	7.62	64%	112.2°
2041-04-10 Wed	56	—	unknown	03:00–05:10 (good, 2.17 h)	87.2° 09:00	7.56	73%	115.2°
2041-04-11 Thu	52	—	unknown	02:55–05:10 (good, 2.25 h)	87.3° 09:00	7.5	81%	117.2°
2041-04-12 Fri	51	—	unknown	02:55–05:05 (good, 2.17 h)	87.3° 08:55	7.44	88%	117.9°
2041-04-13 Sat	50	—	unknown	02:50–05:05 (good, 2.25 h)	87.3° 08:50	7.39	94%	117.3°
2041-04-14 Sun	49	—	unknown	02:50–05:05 (good, 2.25 h)	87.3° 08:45	7.33	98%	115.3°
2041-04-15 Mon	47	—	unknown	02:50–05:00 (good, 2.17 h)	87.2° 08:40	7.27	100%	112.2°
2041-04-16 Tue	45	—	unknown	02:45–05:00 (good, 2.25 h)	87.3° 08:40	7.21	100%	107.9°
2041-04-17 Wed	43	—	unknown	02:45–04:55 (good, 2.17 h)	87.3° 08:35	7.16	98%	102.8°
2041-04-18 Thu	42	—	unknown	02:45–04:55 (good, 2.17 h)	87.3° 08:30	7.1	94%	97.0°
2041-04-19 Fri	42	—	unknown	02:40–04:55 (good, 2.25 h)	87.3° 08:25	7.04	88%	90.8°
2041-04-20 Sat	43	—	unknown	02:30–04:50 (good, 2.33 h)	87.2° 08:25	6.98	79%	84.5°
2041-04-21 Sun	46	—	unknown	02:25–04:50 (good, 2.42 h)	87.3° 08:20	6.92	70%	78.4°
2041-04-22 Mon	55	—	unknown	02:00–04:50 (good, 2.83 h)	87.3° 08:15	6.87	59%	72.8°
2041-04-23 Tue	63	—	unknown	01:55–04:45 (good, 2.83 h)	87.3° 08:10	6.81	48%	68.0°
2041-04-24 Wed	70	—	unknown	01:50–04:45 (good, 2.92 h)	87.2° 08:05	6.75	36%	64.4°
2041-04-25 Thu	73	—	unknown	01:50–04:40 (good, 2.83 h)	87.3° 08:05	6.69	26%	62.5°
2041-04-26 Fri	75	—	unknown	01:45–04:40 (good, 2.92 h)	87.3° 08:00	6.63	16%	62.3°
2041-04-27 Sat	78	—	unknown	01:40–04:40 (good, 3.0 h)	87.3° 07:55	6.57	8%	64.1°
2041-04-28 Sun	78	—	unknown	01:35–04:35 (good, 3.0 h)	87.3° 07:50	6.52	3%	67.5°
2041-04-29 Mon	79	—	unknown	01:30–04:35 (good, 3.08 h)	87.2° 07:45	6.46	0%	72.2°
2041-04-30 Tue	79	—	unknown	01:30–04:30 (good, 3.0 h)	87.3° 07:45	6.4	0%	77.8°
2041-05-01 Wed	81	—	unknown	01:25–04:30 (good, 3.08 h)	87.3° 07:40	6.34	2%	83.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-04-02&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.