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: 07-28 (100), 07-29 (100), 07-30 (100), 07-31 (100), 08-01 (100) — by astronomy; check the weather when the night is within four days.

2041-07-28astronomy score per night — click a bar for that night2041-08-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2041-08-08 Thu	100	—	unknown	23:05–04:35 (good, 5.5 h)	89.8° 04:55	6.26	86%	112.9°
2041-08-09 Fri	100	—	unknown	23:10–04:40 (good, 5.5 h)	89.8° 04:50	6.32	93%	101.3°
2041-08-10 Sat	81	—	unknown	23:15–04:40 (good, 5.42 h)	89.7° 04:45	6.38	98%	89.0°
2041-08-11 Sun	71	—	unknown	00:45–04:40 (good, 3.92 h)	89.5° 04:45	6.43	100%	76.6°
2041-08-12 Mon	58	—	unknown	04:25–04:45 (good, 0.33 h)	89.7° 04:40	6.49	99%	64.4°
2041-08-13 Tue	46	—	unknown	22:10–04:45 (marginal, 6.58 h)	89.8° 04:35	6.55	95%	53.1°
2041-08-14 Wed	44	—	unknown	22:10–04:45 (marginal, 6.58 h)	89.8° 04:30	6.61	88%	43.3°
2041-08-15 Thu	61	—	unknown	22:25–22:35 (good, 0.17 h)	89.6° 04:25	6.66	79%	36.6°
2041-08-16 Fri	81	—	unknown	00:10–01:45 (good, 1.58 h)	89.6° 04:25	6.72	69%	34.2°
2041-08-17 Sat	84	—	unknown	22:15–04:35 (good, 6.33 h)	89.7° 04:20	6.78	59%	36.7°
2041-08-18 Sun	88	—	unknown	22:10–04:55 (good, 6.75 h)	89.8° 04:15	6.84	48%	42.9°
2041-08-19 Mon	93	—	unknown	22:05–04:55 (good, 6.83 h)	89.7° 04:10	6.89	38%	51.1°
2041-08-20 Tue	99	—	unknown	22:05–04:55 (good, 6.83 h)	89.6° 04:05	6.95	28%	60.3°
2041-08-21 Wed	100	—	unknown	22:00–04:55 (good, 6.92 h)	89.6° 04:05	7.01	20%	70.1°
2041-08-22 Thu	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.8° 04:00	7.07	12%	80.0°
2041-08-23 Fri	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.8° 03:55	7.12	7%	89.9°
2041-08-24 Sat	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.7° 03:50	7.18	3%	99.8°
2041-08-25 Sun	100	—	unknown	21:50–05:05 (good, 7.25 h)	89.5° 03:45	7.24	1%	109.5°
2041-08-26 Mon	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.7° 03:45	7.29	0%	118.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-07-28&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.