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: 09-05 (100), 09-06 (100), 09-07 (100), 09-08 (100), 09-17 (100) — by astronomy; check the weather when the night is within four days.

2041-09-05astronomy score per night — click a bar for that night2041-10-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-09-05 Thu	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.8° 03:05	7.85	73%	106.1°
2041-09-06 Fri	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.8° 03:00	7.91	83%	94.4°
2041-09-07 Sat	100	—	unknown	21:40–05:20 (good, 7.67 h)	89.7° 02:55	7.96	91%	82.2°
2041-09-08 Sun	100	—	unknown	23:35–05:20 (good, 5.75 h)	89.5° 02:50	8.02	96%	70.0°
2041-09-09 Mon	64	—	unknown	04:30–05:25 (good, 0.92 h)	89.7° 02:50	8.07	100%	58.1°
2041-09-10 Tue	52	—	unknown	21:15–05:25 (marginal, 8.17 h)	89.8° 02:45	8.13	100%	47.3°
2041-09-11 Wed	45	—	unknown	21:15–05:25 (marginal, 8.17 h)	89.8° 02:40	8.18	96%	38.9°
2041-09-12 Thu	49	—	unknown	21:15–05:25 (marginal, 8.17 h)	89.6° 02:35	8.23	91%	34.4°
2041-09-13 Fri	82	—	unknown	21:10–21:25 (good, 0.25 h)	89.5° 02:35	8.29	83%	35.1°
2041-09-14 Sat	86	—	unknown	21:10–00:45 (good, 3.58 h)	89.7° 02:30	8.34	74%	40.4°
2041-09-15 Sun	91	—	unknown	21:05–04:30 (good, 7.42 h)	89.8° 02:25	8.39	63%	48.3°
2041-09-16 Mon	96	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:20	8.44	53%	57.6°
2041-09-17 Tue	100	—	unknown	21:05–05:35 (good, 8.5 h)	89.6° 02:15	8.5	43%	67.4°
2041-09-18 Wed	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.6° 02:15	8.55	33%	77.3°
2041-09-19 Thu	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.7° 02:10	8.6	25%	87.3°
2041-09-20 Fri	100	—	unknown	20:55–05:35 (good, 8.67 h)	89.8° 02:05	8.65	17%	97.2°
2041-09-21 Sat	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.7° 02:00	8.7	10%	106.9°
2041-09-22 Sun	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.5° 01:55	8.75	5%	116.4°
2041-09-23 Mon	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.6° 01:55	8.8	2%	125.3°
2041-09-24 Tue	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.8° 01:50	8.85	0%	133.5°
2041-09-25 Wed	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.8° 01:45	8.9	0%	140.3°
2041-09-26 Thu	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.6° 01:40	8.95	2%	144.8°
2041-09-27 Fri	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.5° 01:40	9.0	6%	146.0°
2041-09-28 Sat	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.7° 01:35	9.05	12%	143.4°
2041-09-29 Sun	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.8° 01:30	9.1	19%	137.6°
2041-09-30 Mon	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.7° 01:25	9.15	27%	129.6°
2041-10-01 Tue	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.6° 01:20	9.2	37%	120.1°
2041-10-02 Wed	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.6° 01:20	9.24	48%	109.7°
2041-10-03 Thu	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:15	9.29	59%	98.5°
2041-10-04 Fri	100	—	unknown	20:30–05:50 (good, 9.33 h)	89.8° 01:10	9.34	70%	86.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-09-05&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.