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: 12-07 (100), 12-08 (100), 12-09 (100), 12-10 (100), 12-11 (100) — by astronomy; check the weather when the night is within four days.

2039-12-07astronomy score per night — click a bar for that night2040-01-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-12-07 Wed	100	—	unknown	18:35–02:00 (good, 7.42 h)	89.8° 20:00	11.42	59%	116.7°
2039-12-08 Thu	100	—	unknown	18:35–02:00 (good, 7.42 h)	89.6° 19:55	11.43	49%	125.6°
2039-12-09 Fri	100	—	unknown	18:35–02:00 (good, 7.42 h)	89.5° 19:55	11.44	39%	133.6°
2039-12-10 Sat	100	—	unknown	18:35–02:00 (good, 7.42 h)	89.7° 19:50	11.45	29%	139.8°
2039-12-11 Sun	100	—	unknown	18:35–01:55 (good, 7.33 h)	89.8° 19:45	11.46	19%	142.9°
2039-12-12 Mon	100	—	unknown	18:35–01:50 (good, 7.25 h)	89.7° 19:40	11.47	11%	141.5°
2039-12-13 Tue	100	—	unknown	18:35–01:45 (good, 7.17 h)	89.6° 19:35	11.48	5%	135.7°
2039-12-14 Wed	100	—	unknown	18:35–01:40 (good, 7.08 h)	89.6° 19:35	11.48	1%	126.8°
2039-12-15 Thu	100	—	unknown	18:35–01:40 (good, 7.08 h)	89.7° 19:30	11.49	0%	116.0°
2039-12-16 Fri	100	—	unknown	18:35–01:35 (good, 7.0 h)	89.8° 19:25	11.5	2%	104.3°
2039-12-17 Sat	100	—	unknown	18:35–01:30 (good, 6.92 h)	89.7° 19:20	11.5	8%	92.4°
2039-12-18 Sun	100	—	unknown	18:35–01:25 (good, 6.83 h)	89.5° 19:15	11.5	15%	80.6°
2039-12-19 Mon	100	—	unknown	18:35–01:20 (good, 6.75 h)	89.6° 19:15	11.51	24%	69.4°
2039-12-20 Tue	96	—	unknown	18:35–01:20 (good, 6.75 h)	89.8° 19:10	11.51	34%	59.1°
2039-12-21 Wed	87	—	unknown	18:35–01:15 (good, 6.67 h)	89.8° 19:05	11.51	45%	50.1°
2039-12-22 Thu	78	—	unknown	18:35–01:10 (good, 6.58 h)	89.7° 19:00	11.51	55%	43.0°
2039-12-23 Fri	60	—	unknown	21:40–21:45 (good, 0.08 h)	89.5° 19:00	11.51	65%	38.4°
2039-12-24 Sat	44	—	unknown	18:40–01:25 (marginal, 6.75 h)	89.7° 18:55	11.5	74%	37.0°
2039-12-25 Sun	35	—	unknown	18:40–01:10 (marginal, 6.5 h)	89.8° 18:50	11.5	82%	39.1°
2039-12-26 Mon	33	—	unknown	18:40–00:50 (marginal, 6.17 h)	89.7° 18:45	11.5	89%	43.9°
2039-12-27 Tue	34	—	unknown	18:40–00:40 (marginal, 6.0 h)	89.6° 18:40	11.49	94%	50.7°
2039-12-28 Wed	41	—	unknown	18:40–00:35 (marginal, 5.92 h)	89.6° 18:40	11.49	98%	58.6°
2039-12-29 Thu	51	—	unknown	18:40–19:10 (good, 0.5 h)	89.7° 18:35	11.48	100%	67.4°
2039-12-30 Fri	65	—	unknown	18:40–21:15 (good, 2.58 h)	89.8° 18:30	11.47	100%	76.5°
2039-12-31 Sat	77	—	unknown	18:45–22:25 (good, 3.67 h)	89.7° 18:25	11.46	98%	86.0°
2040-01-01 Sun	100	—	unknown	18:45–23:30 (good, 4.75 h)	89.5° 18:20	11.45	95%	95.5°
2040-01-02 Mon	100	—	unknown	18:45–00:05 (good, 5.33 h)	89.6° 18:20	11.44	90%	105.1°
2040-01-03 Tue	100	—	unknown	18:45–00:10 (good, 5.42 h)	89.8° 18:15	11.43	83%	114.5°
2040-01-04 Wed	100	—	unknown	18:45–00:10 (good, 5.42 h)	89.8° 18:10	11.42	75%	123.5°
2040-01-05 Thu	100	—	unknown	18:45–00:10 (good, 5.42 h)	89.7° 18:05	11.41	66%	131.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-12-07&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.