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: 09-09 (100), 09-10 (100), 09-11 (100), 09-12 (100), 09-13 (100) — by astronomy; check the weather when the night is within four days.

2045-09-09astronomy score per night — click a bar for that night2045-10-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-09-09 Sat	100	—	unknown	21:20–05:25 (good, 8.08 h)	89.7° 02:50	8.07	2%	118.2°
2045-09-10 Sun	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.8° 02:45	8.13	0%	130.5°
2045-09-11 Mon	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.8° 02:40	8.18	1%	141.3°
2045-09-12 Tue	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.6° 02:35	8.23	5%	149.0°
2045-09-13 Wed	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.6° 02:35	8.29	11%	151.4°
2045-09-14 Thu	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.7° 02:30	8.34	20%	147.7°
2045-09-15 Fri	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.8° 02:25	8.39	29%	140.1°
2045-09-16 Sat	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:20	8.45	39%	130.7°
2045-09-17 Sun	100	—	unknown	21:05–05:35 (good, 8.5 h)	89.6° 02:15	8.5	49%	120.5°
2045-09-18 Mon	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.6° 02:15	8.55	58%	110.1°
2045-09-19 Tue	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.8° 02:10	8.6	68%	99.7°
2045-09-20 Wed	100	—	unknown	20:55–05:35 (good, 8.67 h)	89.8° 02:05	8.65	76%	89.2°
2045-09-21 Thu	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.7° 02:00	8.7	84%	78.8°
2045-09-22 Fri	100	—	unknown	22:35–05:40 (good, 7.08 h)	89.5° 01:55	8.75	90%	68.6°
2045-09-23 Sat	95	—	unknown	02:45–05:40 (good, 2.92 h)	89.7° 01:55	8.81	95%	58.5°
2045-09-24 Sun	59	—	unknown	20:50–05:40 (marginal, 8.83 h)	89.8° 01:50	8.86	98%	48.9°
2045-09-25 Mon	47	—	unknown	20:50–05:40 (marginal, 8.83 h)	89.8° 01:45	8.91	100%	40.2°
2045-09-26 Tue	34	—	unknown	20:45–00:40 (marginal, 3.92 h)	89.6° 01:40	8.96	100%	33.0°
2045-09-27 Wed	35	—	unknown	20:45–00:35 (marginal, 3.83 h)	89.6° 01:40	9.0	97%	29.0°
2045-09-28 Thu	42	—	unknown	20:45–01:55 (marginal, 5.17 h)	89.7° 01:35	9.05	93%	29.6°
2045-09-29 Fri	55	—	unknown	20:40–05:45 (marginal, 9.08 h)	89.8° 01:30	9.1	87%	34.7°
2045-09-30 Sat	87	—	unknown	20:40–23:30 (good, 2.83 h)	89.7° 01:25	9.15	79%	43.0°
2045-10-01 Sun	93	—	unknown	20:35–02:55 (good, 6.33 h)	89.6° 01:20	9.2	70%	53.0°
2045-10-02 Mon	100	—	unknown	20:35–05:40 (good, 9.08 h)	89.6° 01:20	9.25	59%	64.1°
2045-10-03 Tue	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.8° 01:15	9.29	48%	75.9°
2045-10-04 Wed	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.8° 01:10	9.34	37%	88.2°
2045-10-05 Thu	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.7° 01:05	9.39	26%	100.7°
2045-10-06 Fri	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.5° 01:00	9.43	17%	113.3°
2045-10-07 Sat	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.7° 01:00	9.48	9%	125.5°
2045-10-08 Sun	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.8° 00:55	9.53	3%	136.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-09-09&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.