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: 12-15 (100), 12-16 (100), 12-17 (100), 12-18 (100), 12-19 (100) — by astronomy; check the weather when the night is within four days.

2027-12-08astronomy score per night — click a bar for that night2028-01-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-12-08 Wed	49	—	unknown	18:35–02:30 (marginal, 7.92 h)	89.6° 19:55	11.43	75%	30.2°
2027-12-09 Thu	33	—	unknown	18:35–02:10 (marginal, 7.58 h)	89.5° 19:50	11.44	83%	28.3°
2027-12-10 Fri	26	—	unknown	18:35–01:45 (marginal, 7.17 h)	89.6° 19:50	11.45	90%	31.6°
2027-12-11 Sat	28	—	unknown	18:35–23:10 (marginal, 4.58 h)	89.7° 19:45	11.46	96%	39.2°
2027-12-12 Sun	38	—	unknown	18:35–01:20 (marginal, 6.75 h)	89.7° 19:40	11.47	99%	49.5°
2027-12-13 Mon	56	—	unknown	18:35–18:55 (good, 0.33 h)	89.6° 19:35	11.48	100%	61.2°
2027-12-14 Tue	72	—	unknown	18:35–21:50 (good, 3.25 h)	89.5° 19:35	11.48	98%	73.7°
2027-12-15 Wed	100	—	unknown	18:35–23:45 (good, 5.17 h)	89.6° 19:30	11.49	93%	86.5°
2027-12-16 Thu	100	—	unknown	18:35–01:05 (good, 6.5 h)	89.7° 19:25	11.5	86%	99.5°
2027-12-17 Fri	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.7° 19:20	11.5	77%	112.2°
2027-12-18 Sat	100	—	unknown	18:35–01:20 (good, 6.75 h)	89.5° 19:15	11.5	66%	124.3°
2027-12-19 Sun	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.5° 19:15	11.51	55%	135.4°
2027-12-20 Mon	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.7° 19:10	11.51	44%	144.7°
2027-12-21 Tue	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.7° 19:05	11.51	33%	150.7°
2027-12-22 Wed	100	—	unknown	18:35–01:10 (good, 6.58 h)	89.6° 19:00	11.51	24%	151.5°
2027-12-23 Thu	100	—	unknown	18:40–01:05 (good, 6.42 h)	89.5° 18:55	11.51	15%	147.0°
2027-12-24 Fri	100	—	unknown	18:40–01:00 (good, 6.33 h)	89.6° 18:55	11.5	8%	139.1°
2027-12-25 Sat	100	—	unknown	18:40–01:00 (good, 6.33 h)	89.7° 18:50	11.5	4%	129.6°
2027-12-26 Sun	100	—	unknown	18:40–00:55 (good, 6.25 h)	89.7° 18:45	11.5	1%	119.3°
2027-12-27 Mon	100	—	unknown	18:40–00:50 (good, 6.17 h)	89.6° 18:40	11.49	0%	108.7°
2027-12-28 Tue	100	—	unknown	18:40–00:45 (good, 6.08 h)	89.5° 18:40	11.49	1%	98.0°
2027-12-29 Wed	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.6° 18:35	11.48	4%	87.3°
2027-12-30 Thu	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.7° 18:30	11.47	9%	76.8°
2027-12-31 Fri	100	—	unknown	18:45–00:35 (good, 5.83 h)	89.7° 18:25	11.46	15%	66.5°
2028-01-01 Sat	96	—	unknown	18:45–00:30 (good, 5.75 h)	89.6° 18:20	11.45	22%	56.6°
2028-01-02 Sun	89	—	unknown	18:45–00:25 (good, 5.67 h)	89.5° 18:20	11.44	30%	47.1°
2028-01-03 Mon	81	—	unknown	18:45–00:25 (good, 5.67 h)	89.7° 18:15	11.43	39%	38.6°
2028-01-04 Tue	69	—	unknown	18:45–23:50 (good, 5.08 h)	89.7° 18:10	11.42	49%	31.8°
2028-01-05 Wed	51	—	unknown	18:45–00:45 (marginal, 6.0 h)	89.7° 18:05	11.41	58%	28.3°
2028-01-06 Thu	35	—	unknown	18:45–00:30 (marginal, 5.75 h)	89.5° 18:00	11.4	68%	29.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-12-08&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.