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 Andromeda Galaxy: 07-24 (100), 07-25 (100), 07-26 (100), 07-27 (100), 07-28 (100) — by astronomy; check the weather when the night is within four days.

2041-07-09astronomy score per night — click a bar for that night2041-08-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-07-09 Tue	79	—	unknown	00:55–03:50 (good, 2.92 h)	89.5° 06:50	4.78	82%	137.7°
2041-07-10 Wed	82	—	unknown	00:55–03:55 (good, 3.0 h)	89.6° 06:50	4.81	89%	129.4°
2041-07-11 Thu	82	—	unknown	00:50–03:55 (good, 3.08 h)	89.8° 06:45	4.85	95%	119.2°
2041-07-12 Fri	66	—	unknown	00:55–03:55 (good, 3.0 h)	89.8° 06:40	4.89	99%	107.9°
2041-07-13 Sat	57	—	unknown	01:00–03:55 (good, 2.92 h)	89.7° 06:35	4.93	100%	95.9°
2041-07-14 Sun	49	—	unknown	01:35–04:00 (good, 2.42 h)	89.5° 06:35	4.97	98%	83.7°
2041-07-15 Mon	43	—	unknown	02:40–04:00 (good, 1.33 h)	89.7° 06:30	5.01	93%	71.5°
2041-07-16 Tue	38	—	unknown	03:35–04:00 (good, 0.42 h)	89.8° 06:25	5.06	86%	59.9°
2041-07-17 Wed	39	—	unknown	23:45–04:05 (marginal, 4.33 h)	89.8° 06:20	5.1	77%	49.4°
2041-07-18 Thu	44	—	unknown	01:55–04:05 (good, 2.17 h)	89.6° 06:15	5.15	66%	40.8°
2041-07-19 Fri	60	—	unknown	00:10–04:05 (good, 3.92 h)	89.6° 06:15	5.19	55%	35.6°
2041-07-20 Sat	74	—	unknown	00:05–04:05 (good, 4.0 h)	89.7° 06:10	5.24	44%	34.7°
2041-07-21 Sun	84	—	unknown	00:00–04:10 (good, 4.17 h)	89.8° 06:05	5.29	34%	38.2°
2041-07-22 Mon	90	—	unknown	23:55–04:10 (good, 4.25 h)	89.7° 06:00	5.34	24%	44.9°
2041-07-23 Tue	95	—	unknown	23:55–04:10 (good, 4.25 h)	89.5° 05:55	5.39	16%	53.3°
2041-07-24 Wed	100	—	unknown	23:50–04:15 (good, 4.42 h)	89.6° 05:55	5.44	9%	62.7°
2041-07-25 Thu	100	—	unknown	23:45–04:15 (good, 4.5 h)	89.8° 05:50	5.49	4%	72.5°
2041-07-26 Fri	100	—	unknown	23:40–04:15 (good, 4.58 h)	89.8° 05:45	5.54	1%	82.5°
2041-07-27 Sat	100	—	unknown	23:40–04:20 (good, 4.67 h)	89.7° 05:40	5.6	0%	92.5°
2041-07-28 Sun	100	—	unknown	23:35–04:20 (good, 4.75 h)	89.5° 05:40	5.65	1%	102.3°
2041-07-29 Mon	100	—	unknown	23:30–04:20 (good, 4.83 h)	89.7° 05:35	5.7	3%	111.9°
2041-07-30 Tue	100	—	unknown	23:25–04:25 (good, 5.0 h)	89.8° 05:30	5.76	8%	121.0°
2041-07-31 Wed	100	—	unknown	23:20–04:25 (good, 5.08 h)	89.8° 05:25	5.81	13%	129.5°
2041-08-01 Thu	100	—	unknown	23:20–04:25 (good, 5.08 h)	89.6° 05:20	5.87	20%	137.0°
2041-08-02 Fri	100	—	unknown	23:15–04:30 (good, 5.25 h)	89.6° 05:20	5.92	28%	142.6°
2041-08-03 Sat	100	—	unknown	23:15–04:30 (good, 5.25 h)	89.7° 05:15	5.98	38%	145.5°
2041-08-04 Sun	100	—	unknown	23:10–04:30 (good, 5.33 h)	89.8° 05:10	6.03	47%	144.7°
2041-08-05 Mon	100	—	unknown	23:10–04:30 (good, 5.33 h)	89.7° 05:05	6.09	57%	140.3°
2041-08-06 Tue	100	—	unknown	23:05–04:35 (good, 5.5 h)	89.5° 05:00	6.15	68%	133.0°
2041-08-07 Wed	100	—	unknown	23:05–04:35 (good, 5.5 h)	89.6° 05:00	6.2	77%	123.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-07-09&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.