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: 01-19 (100), 01-20 (100), 01-21 (100), 01-22 (100), 01-23 (100) — by astronomy; check the weather when the night is within four days.

2041-01-08astronomy score per night — click a bar for that night2041-02-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-01-08 Tue	74	—	unknown	18:50–23:40 (good, 4.83 h)	89.6° 17:50	11.35	45%	39.3°
2041-01-09 Wed	56	—	unknown	18:50–22:05 (good, 3.25 h)	89.5° 17:50	11.34	56%	35.7°
2041-01-10 Thu	40	—	unknown	18:50–00:15 (marginal, 5.42 h)	89.7° 17:45	11.32	66%	36.2°
2041-01-11 Fri	31	—	unknown	18:55–00:00 (marginal, 5.08 h)	89.8° 17:40	11.3	75%	40.5°
2041-01-12 Sat	29	—	unknown	18:55–23:45 (marginal, 4.83 h)	89.7° 17:35	11.28	83%	47.3°
2041-01-13 Sun	30	—	unknown	18:55–23:35 (marginal, 4.67 h)	89.6° 17:30	11.26	90%	55.5°
2041-01-14 Mon	35	—	unknown	18:55–23:35 (marginal, 4.67 h)	89.6° 17:30	11.24	95%	64.6°
2041-01-15 Tue	43	—	unknown	18:55–19:40 (good, 0.75 h)	89.8° 17:25	11.22	98%	74.1°
2041-01-16 Wed	54	—	unknown	18:55–20:55 (good, 2.0 h)	89.8° 17:20	11.2	100%	83.7°
2041-01-17 Thu	65	—	unknown	19:00–22:00 (good, 3.0 h)	89.7° 17:15	11.17	100%	93.4°
2041-01-18 Fri	78	—	unknown	19:00–22:50 (good, 3.83 h)	89.5° 17:10	11.15	97%	103.0°
2041-01-19 Sat	100	—	unknown	19:00–23:00 (good, 4.0 h)	89.7° 17:10	11.12	94%	112.4°
2041-01-20 Sun	100	—	unknown	19:00–23:00 (good, 4.0 h)	89.8° 17:05	11.1	88%	121.4°
2041-01-21 Mon	100	—	unknown	19:05–23:00 (good, 3.92 h)	89.8° 17:00	11.07	82%	129.8°
2041-01-22 Tue	100	—	unknown	19:05–23:00 (good, 3.92 h)	89.6° 16:55	11.05	74%	137.0°
2041-01-23 Wed	100	—	unknown	19:05–23:00 (good, 3.92 h)	89.5° 16:55	11.02	65%	142.4°
2041-01-24 Thu	100	—	unknown	19:05–23:00 (good, 3.92 h)	89.7° 16:50	10.99	55%	144.7°
2041-01-25 Fri	99	—	unknown	19:05–22:55 (good, 3.83 h)	89.8° 16:45	10.96	45%	143.3°
2041-01-26 Sat	97	—	unknown	19:10–22:50 (good, 3.67 h)	89.7° 16:40	10.93	34%	138.1°
2041-01-27 Sun	95	—	unknown	19:10–22:45 (good, 3.58 h)	89.6° 16:35	10.9	24%	130.0°
2041-01-28 Mon	93	—	unknown	19:10–22:40 (good, 3.5 h)	89.6° 16:35	10.87	15%	120.0°
2041-01-29 Tue	90	—	unknown	19:10–22:40 (good, 3.5 h)	89.7° 16:30	10.84	8%	108.7°
2041-01-30 Wed	88	—	unknown	19:10–22:35 (good, 3.42 h)	89.8° 16:25	10.81	3%	96.6°
2041-01-31 Thu	85	—	unknown	19:15–22:30 (good, 3.25 h)	89.7° 16:20	10.78	0%	84.1°
2041-02-01 Fri	83	—	unknown	19:15–22:25 (good, 3.17 h)	89.5° 16:15	10.75	1%	71.8°
2041-02-02 Sat	80	—	unknown	19:15–22:20 (good, 3.08 h)	89.6° 16:15	10.71	5%	60.0°
2041-02-03 Sun	73	—	unknown	19:15–22:20 (good, 3.08 h)	89.8° 16:10	10.68	11%	49.5°
2041-02-04 Mon	63	—	unknown	19:20–22:15 (good, 2.92 h)	89.8° 16:05	10.64	19%	41.1°
2041-02-05 Tue	51	—	unknown	19:20–21:55 (good, 2.58 h)	89.6° 16:00	10.61	29%	36.1°
2041-02-06 Wed	40	—	unknown	19:20–21:40 (good, 2.33 h)	89.5° 16:00	10.57	39%	35.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-01-08&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.