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: 12-27 (100), 12-28 (100), 12-29 (100), 12-30 (100), 12-31 (100) — by astronomy; check the weather when the night is within four days.

2034-12-20astronomy score per night — click a bar for that night2035-01-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-12-20 Wed	49	—	unknown	18:35–01:45 (marginal, 7.17 h)	89.6° 19:10	11.51	74%	36.5°
2034-12-21 Thu	38	—	unknown	18:35–01:25 (marginal, 6.83 h)	89.7° 19:05	11.51	83%	39.6°
2034-12-22 Fri	37	—	unknown	18:35–01:05 (marginal, 6.5 h)	89.8° 19:00	11.51	91%	46.7°
2034-12-23 Sat	43	—	unknown	18:40–01:00 (marginal, 6.33 h)	89.6° 18:55	11.51	97%	56.5°
2034-12-24 Sun	57	—	unknown	18:40–19:30 (good, 0.83 h)	89.5° 18:55	11.5	100%	67.6°
2034-12-25 Mon	73	—	unknown	18:40–21:55 (good, 3.25 h)	89.6° 18:50	11.5	99%	79.5°
2034-12-26 Tue	82	—	unknown	18:40–23:20 (good, 4.67 h)	89.8° 18:45	11.5	96%	91.4°
2034-12-27 Wed	100	—	unknown	18:40–00:20 (good, 5.67 h)	89.7° 18:40	11.49	91%	103.0°
2034-12-28 Thu	100	—	unknown	18:40–00:30 (good, 5.83 h)	89.6° 18:35	11.48	83%	114.0°
2034-12-29 Fri	100	—	unknown	18:40–00:35 (good, 5.92 h)	89.5° 18:35	11.48	74%	123.9°
2034-12-30 Sat	100	—	unknown	18:40–00:30 (good, 5.83 h)	89.7° 18:30	11.47	65%	132.4°
2034-12-31 Sun	100	—	unknown	18:45–00:30 (good, 5.75 h)	89.8° 18:25	11.46	55%	138.9°
2035-01-01 Mon	100	—	unknown	18:45–00:30 (good, 5.75 h)	89.7° 18:20	11.45	45%	142.7°
2035-01-02 Tue	100	—	unknown	18:45–00:25 (good, 5.67 h)	89.5° 18:15	11.44	36%	143.2°
2035-01-03 Wed	100	—	unknown	18:45–00:20 (good, 5.58 h)	89.6° 18:15	11.43	27%	140.5°
2035-01-04 Thu	100	—	unknown	18:45–00:20 (good, 5.58 h)	89.7° 18:10	11.42	19%	135.2°
2035-01-05 Fri	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.8° 18:05	11.4	12%	128.1°
2035-01-06 Sat	100	—	unknown	18:50–00:10 (good, 5.33 h)	89.6° 18:00	11.39	7%	119.9°
2035-01-07 Sun	100	—	unknown	18:50–00:05 (good, 5.25 h)	89.5° 17:55	11.38	3%	111.0°
2035-01-08 Mon	100	—	unknown	18:50–00:00 (good, 5.17 h)	89.6° 17:55	11.36	1%	101.6°
2035-01-09 Tue	100	—	unknown	18:50–00:00 (good, 5.17 h)	89.8° 17:50	11.34	0%	91.8°
2035-01-10 Wed	100	—	unknown	18:50–23:55 (good, 5.08 h)	89.7° 17:45	11.33	2%	82.0°
2035-01-11 Thu	100	—	unknown	18:50–23:50 (good, 5.0 h)	89.6° 17:40	11.31	5%	72.1°
2035-01-12 Fri	100	—	unknown	18:55–23:45 (good, 4.83 h)	89.5° 17:40	11.29	11%	62.4°
2035-01-13 Sat	93	—	unknown	18:55–23:45 (good, 4.83 h)	89.7° 17:35	11.27	18%	53.3°
2035-01-14 Sun	88	—	unknown	18:55–23:40 (good, 4.75 h)	89.8° 17:30	11.25	26%	45.3°
2035-01-15 Mon	79	—	unknown	18:55–23:35 (good, 4.67 h)	89.7° 17:25	11.23	36%	39.4°
2035-01-16 Tue	61	—	unknown	18:55–23:05 (good, 4.17 h)	89.5° 17:20	11.21	47%	36.7°
2035-01-17 Wed	45	—	unknown	19:00–20:25 (good, 1.42 h)	89.6° 17:20	11.18	58%	38.4°
2035-01-18 Thu	36	—	unknown	19:00–23:45 (marginal, 4.75 h)	89.7° 17:15	11.16	69%	44.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-12-20&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.