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: 09-20 (100), 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100) — by astronomy; check the weather when the night is within four days.

2041-09-20astronomy score per night — click a bar for that night2041-10-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2041-10-05 Sat	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.7° 01:05	9.39	80%	75.0°
2041-10-06 Sun	97	—	unknown	21:55–05:55 (good, 8.0 h)	89.5° 01:00	9.43	88%	63.2°
2041-10-07 Mon	88	—	unknown	03:35–05:55 (good, 2.33 h)	89.6° 01:00	9.48	95%	52.0°
2041-10-08 Tue	50	—	unknown	20:25–05:55 (marginal, 9.5 h)	89.8° 00:55	9.53	99%	42.4°
2041-10-09 Wed	43	—	unknown	20:25–06:00 (marginal, 9.58 h)	89.8° 00:50	9.57	100%	35.8°
2041-10-10 Thu	45	—	unknown	20:20–01:20 (marginal, 5.0 h)	89.6° 00:45	9.62	98%	34.1°
2041-10-11 Fri	55	—	unknown	20:20–06:00 (marginal, 9.67 h)	89.5° 00:45	9.66	94%	37.6°
2041-10-12 Sat	88	—	unknown	20:20–22:20 (good, 2.0 h)	89.7° 00:40	9.71	87%	44.9°
2041-10-13 Sun	94	—	unknown	20:15–00:50 (good, 4.58 h)	89.8° 00:35	9.75	78%	54.0°
2041-10-14 Mon	100	—	unknown	20:15–04:00 (good, 7.75 h)	89.7° 00:30	9.79	69%	63.9°
2041-10-15 Tue	100	—	unknown	20:15–05:35 (good, 9.33 h)	89.6° 00:25	9.84	60%	74.1°
2041-10-16 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:25	9.88	50%	84.3°
2041-10-17 Thu	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.7° 00:20	9.92	40%	94.3°
2041-10-18 Fri	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.8° 00:15	9.97	31%	104.2°
2041-10-19 Sat	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.7° 00:10	10.01	22%	113.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-09-20&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.