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), 12-21 (100), 12-22 (100) — by astronomy; check the weather when the night is within four days.

2040-12-07astronomy score per night — click a bar for that night2041-01-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-12-07 Fri	100	—	unknown	18:35–02:05 (good, 7.5 h)	89.5° 20:00	11.43	18%	86.1°
2040-12-08 Sat	100	—	unknown	18:35–02:05 (good, 7.5 h)	89.7° 19:55	11.44	27%	74.4°
2040-12-09 Sun	100	—	unknown	18:35–02:00 (good, 7.42 h)	89.8° 19:50	11.45	38%	63.3°
2040-12-10 Mon	90	—	unknown	18:35–01:55 (good, 7.33 h)	89.8° 19:45	11.46	49%	53.1°
2040-12-11 Tue	82	—	unknown	18:35–01:50 (good, 7.25 h)	89.6° 19:40	11.47	60%	44.4°
2040-12-12 Wed	57	—	unknown	18:35–02:20 (marginal, 7.75 h)	89.6° 19:40	11.48	71%	38.3°
2040-12-13 Thu	42	—	unknown	18:35–02:05 (marginal, 7.5 h)	89.7° 19:35	11.48	80%	35.6°
2040-12-14 Fri	34	—	unknown	18:35–01:40 (marginal, 7.08 h)	89.8° 19:30	11.49	88%	37.0°
2040-12-15 Sat	32	—	unknown	18:35–01:20 (marginal, 6.75 h)	89.7° 19:25	11.49	94%	42.0°
2040-12-16 Sun	37	—	unknown	18:35–01:10 (marginal, 6.58 h)	89.5° 19:20	11.5	98%	49.2°
2040-12-17 Mon	47	—	unknown	18:35–01:10 (marginal, 6.58 h)	89.6° 19:20	11.5	100%	57.8°
2040-12-18 Tue	62	—	unknown	18:35–19:45 (good, 1.17 h)	89.8° 19:15	11.51	100%	67.0°
2040-12-19 Wed	73	—	unknown	18:35–22:05 (good, 3.5 h)	89.8° 19:10	11.51	98%	76.6°
2040-12-20 Thu	81	—	unknown	18:35–23:15 (good, 4.67 h)	89.7° 19:05	11.51	94%	86.3°
2040-12-21 Fri	100	—	unknown	18:35–00:25 (good, 5.83 h)	89.5° 19:05	11.51	89%	95.9°
2040-12-22 Sat	100	—	unknown	18:35–00:45 (good, 6.17 h)	89.7° 19:00	11.51	83%	105.5°
2040-12-23 Sun	100	—	unknown	18:40–00:50 (good, 6.17 h)	89.8° 18:55	11.5	75%	114.8°
2040-12-24 Mon	100	—	unknown	18:40–00:50 (good, 6.17 h)	89.8° 18:50	11.5	67%	123.6°
2040-12-25 Tue	100	—	unknown	18:40–00:50 (good, 6.17 h)	89.6° 18:45	11.5	58%	131.7°
2040-12-26 Wed	100	—	unknown	18:40–00:50 (good, 6.17 h)	89.6° 18:45	11.49	48%	138.6°
2040-12-27 Thu	100	—	unknown	18:40–00:50 (good, 6.17 h)	89.7° 18:40	11.49	38%	143.2°
2040-12-28 Fri	100	—	unknown	18:40–00:45 (good, 6.08 h)	89.8° 18:35	11.48	28%	144.4°
2040-12-29 Sat	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.7° 18:30	11.47	19%	141.5°
2040-12-30 Sun	100	—	unknown	18:40–00:35 (good, 5.92 h)	89.6° 18:25	11.47	11%	135.0°
2040-12-31 Mon	100	—	unknown	18:45–00:30 (good, 5.75 h)	89.6° 18:25	11.46	5%	125.8°
2041-01-01 Tue	100	—	unknown	18:45–00:30 (good, 5.75 h)	89.8° 18:20	11.45	1%	114.9°
2041-01-02 Wed	100	—	unknown	18:45–00:25 (good, 5.67 h)	89.8° 18:15	11.44	0%	103.1°
2041-01-03 Thu	100	—	unknown	18:45–00:20 (good, 5.58 h)	89.7° 18:10	11.42	2%	90.8°
2041-01-04 Fri	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.5° 18:05	11.41	7%	78.5°
2041-01-05 Sat	100	—	unknown	18:45–00:10 (good, 5.42 h)	89.7° 18:05	11.4	14%	66.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-12-07&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.