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 North America Nebula: 05-01 (81), 04-29 (80), 04-30 (80), 04-28 (78), 04-27 (77) — by astronomy; check the weather when the night is within four days.

2044-04-02astronomy score per night — click a bar for that night2044-05-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-04-02 Sat	54	—	unknown	03:15–05:25 (good, 2.17 h)	87.2° 09:30	7.99	25%	88.2°
2044-04-03 Sun	55	—	unknown	03:15–05:25 (good, 2.17 h)	87.2° 09:30	7.94	36%	95.7°
2044-04-04 Mon	54	—	unknown	03:15–05:20 (good, 2.08 h)	87.2° 09:25	7.88	47%	102.9°
2044-04-05 Tue	55	—	unknown	03:15–05:20 (good, 2.08 h)	87.2° 09:20	7.83	59%	109.5°
2044-04-06 Wed	55	—	unknown	03:10–05:20 (good, 2.17 h)	87.2° 09:15	7.77	70%	115.0°
2044-04-07 Thu	54	—	unknown	03:05–05:15 (good, 2.17 h)	87.2° 09:15	7.71	79%	119.0°
2044-04-08 Fri	50	—	unknown	03:05–05:15 (good, 2.17 h)	87.2° 09:10	7.66	87%	121.4°
2044-04-09 Sat	50	—	unknown	03:00–05:15 (good, 2.25 h)	87.2° 09:05	7.6	94%	121.8°
2044-04-10 Sun	49	—	unknown	03:00–05:10 (good, 2.17 h)	87.2° 09:00	7.54	98%	120.4°
2044-04-11 Mon	49	—	unknown	03:00–05:10 (good, 2.17 h)	87.2° 08:55	7.49	100%	117.4°
2044-04-12 Tue	46	—	unknown	02:55–05:05 (good, 2.17 h)	87.2° 08:55	7.43	100%	113.0°
2044-04-13 Wed	44	—	unknown	02:55–05:05 (good, 2.17 h)	87.2° 08:50	7.37	98%	107.8°
2044-04-14 Thu	44	—	unknown	02:55–05:05 (good, 2.17 h)	87.2° 08:45	7.31	94%	101.9°
2044-04-15 Fri	42	—	unknown	02:50–05:00 (good, 2.17 h)	87.2° 08:40	7.26	88%	95.8°
2044-04-16 Sat	43	—	unknown	02:45–05:00 (good, 2.25 h)	87.2° 08:35	7.2	81%	89.5°
2044-04-17 Sun	43	—	unknown	02:40–04:55 (good, 2.25 h)	87.2° 08:35	7.14	73%	83.2°
2044-04-18 Mon	47	—	unknown	02:15–04:55 (good, 2.67 h)	87.2° 08:30	7.08	65%	77.2°
2044-04-19 Tue	54	—	unknown	02:10–04:55 (good, 2.75 h)	87.2° 08:25	7.02	55%	71.6°
2044-04-20 Wed	59	—	unknown	02:05–04:50 (good, 2.75 h)	87.2° 08:20	6.97	46%	66.6°
2044-04-21 Thu	65	—	unknown	02:00–04:50 (good, 2.83 h)	87.2° 08:20	6.91	36%	62.5°
2044-04-22 Fri	68	—	unknown	02:00–04:45 (good, 2.75 h)	87.2° 08:15	6.85	27%	59.5°
2044-04-23 Sat	73	—	unknown	01:55–04:45 (good, 2.83 h)	87.2° 08:10	6.79	18%	58.1°
2044-04-24 Sun	74	—	unknown	01:50–04:45 (good, 2.92 h)	87.2° 08:05	6.73	11%	58.5°
2044-04-25 Mon	75	—	unknown	01:45–04:40 (good, 2.92 h)	87.2° 08:00	6.67	5%	61.0°
2044-04-26 Tue	76	—	unknown	01:45–04:40 (good, 2.92 h)	87.2° 08:00	6.62	1%	65.3°
2044-04-27 Wed	77	—	unknown	01:40–04:40 (good, 3.0 h)	87.2° 07:55	6.56	0%	71.1°
2044-04-28 Thu	78	—	unknown	01:35–04:35 (good, 3.0 h)	87.2° 07:50	6.5	2%	78.1°
2044-04-29 Fri	80	—	unknown	01:30–04:35 (good, 3.08 h)	87.2° 07:45	6.44	6%	85.7°
2044-04-30 Sat	80	—	unknown	01:25–04:30 (good, 3.08 h)	87.2° 07:40	6.38	14%	93.6°
2044-05-01 Sun	81	—	unknown	01:25–04:30 (good, 3.08 h)	87.2° 07:40	6.33	23%	101.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-04-02&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.