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.

2028-12-15astronomy score per night — click a bar for that night2029-01-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-12-15 Fri	100	—	unknown	18:35–01:35 (good, 7.0 h)	89.7° 19:25	11.49	0%	120.2°
2028-12-16 Sat	100	—	unknown	18:35–01:30 (good, 6.92 h)	89.6° 19:20	11.5	1%	108.6°
2028-12-17 Sun	100	—	unknown	18:35–01:25 (good, 6.83 h)	89.5° 19:20	11.5	4%	97.0°
2028-12-18 Mon	100	—	unknown	18:35–01:25 (good, 6.83 h)	89.7° 19:15	11.51	9%	85.6°
2028-12-19 Tue	100	—	unknown	18:35–01:20 (good, 6.75 h)	89.7° 19:10	11.51	15%	74.5°
2028-12-20 Wed	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.7° 19:05	11.51	23%	63.9°
2028-12-21 Thu	94	—	unknown	18:35–01:10 (good, 6.58 h)	89.5° 19:00	11.51	32%	53.8°
2028-12-22 Fri	87	—	unknown	18:35–01:05 (good, 6.5 h)	89.6° 19:00	11.51	41%	44.6°
2028-12-23 Sat	79	—	unknown	18:40–01:05 (good, 6.42 h)	89.7° 18:55	11.5	50%	36.5°
2028-12-24 Sun	61	—	unknown	21:20–22:05 (good, 0.75 h)	89.7° 18:50	11.5	60%	30.6°
2028-12-25 Mon	44	—	unknown	18:40–01:20 (marginal, 6.67 h)	89.6° 18:45	11.5	69%	28.2°
2028-12-26 Tue	31	—	unknown	18:40–01:00 (marginal, 6.33 h)	89.5° 18:45	11.49	77%	30.4°
2028-12-27 Wed	27	—	unknown	18:40–00:40 (marginal, 6.0 h)	89.6° 18:40	11.49	85%	36.4°
2028-12-28 Thu	29	—	unknown	18:40–00:25 (marginal, 5.75 h)	89.7° 18:35	11.48	92%	45.0°
2028-12-29 Fri	35	—	unknown	18:40–00:25 (marginal, 5.75 h)	89.7° 18:30	11.47	96%	55.2°
2028-12-30 Sat	48	—	unknown	18:40–18:50 (good, 0.17 h)	89.6° 18:25	11.47	99%	66.4°
2028-12-31 Sun	65	—	unknown	18:45–21:20 (good, 2.58 h)	89.5° 18:25	11.46	100%	78.2°
2029-01-01 Mon	80	—	unknown	18:45–22:45 (good, 4.0 h)	89.7° 18:20	11.45	98%	90.4°
2029-01-02 Tue	100	—	unknown	18:45–23:55 (good, 5.17 h)	89.7° 18:15	11.44	94%	102.8°
2029-01-03 Wed	100	—	unknown	18:45–00:05 (good, 5.33 h)	89.7° 18:10	11.42	87%	115.1°
2029-01-04 Thu	100	—	unknown	18:45–00:05 (good, 5.33 h)	89.5° 18:05	11.41	78%	127.0°
2029-01-05 Fri	100	—	unknown	18:45–00:05 (good, 5.33 h)	89.6° 18:05	11.4	68%	137.9°
2029-01-06 Sat	100	—	unknown	18:50–00:10 (good, 5.33 h)	89.7° 18:00	11.38	57%	146.7°
2029-01-07 Sun	100	—	unknown	18:50–00:05 (good, 5.25 h)	89.7° 17:55	11.37	46%	151.5°
2029-01-08 Mon	100	—	unknown	18:50–00:00 (good, 5.17 h)	89.6° 17:50	11.35	35%	150.3°
2029-01-09 Tue	100	—	unknown	18:50–23:55 (good, 5.08 h)	89.5° 17:50	11.34	24%	143.9°
2029-01-10 Wed	100	—	unknown	18:50–23:50 (good, 5.0 h)	89.6° 17:45	11.32	16%	134.5°
2029-01-11 Thu	100	—	unknown	18:55–23:50 (good, 4.92 h)	89.7° 17:40	11.3	8%	123.8°
2029-01-12 Fri	100	—	unknown	18:55–23:45 (good, 4.83 h)	89.7° 17:35	11.28	4%	112.5°
2029-01-13 Sat	100	—	unknown	18:55–23:40 (good, 4.75 h)	89.6° 17:30	11.26	1%	101.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-12-15&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.