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: 01-05 (100), 01-06 (100), 01-21 (100), 01-22 (100), 01-23 (100) — by astronomy; check the weather when the night is within four days.

2030-01-05astronomy score per night — click a bar for that night2030-02-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-01-05 Sat	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.7° 18:05	11.4	4%	78.4°
2030-01-06 Sun	100	—	unknown	18:50–00:10 (good, 5.33 h)	89.7° 18:00	11.39	10%	66.7°
2030-01-07 Mon	97	—	unknown	18:50–00:05 (good, 5.25 h)	89.6° 17:55	11.37	17%	55.8°
2030-01-08 Tue	89	—	unknown	18:50–00:00 (good, 5.17 h)	89.5° 17:50	11.36	25%	45.8°
2030-01-09 Wed	81	—	unknown	18:50–23:55 (good, 5.08 h)	89.6° 17:50	11.34	34%	37.4°
2030-01-10 Thu	69	—	unknown	18:50–23:30 (good, 4.67 h)	89.7° 17:45	11.32	44%	31.3°
2030-01-11 Fri	52	—	unknown	18:50–21:30 (good, 2.67 h)	89.7° 17:40	11.3	53%	28.9°
2030-01-12 Sat	38	—	unknown	18:55–00:10 (marginal, 5.25 h)	89.6° 17:35	11.29	63%	30.8°
2030-01-13 Sun	31	—	unknown	18:55–23:55 (marginal, 5.0 h)	89.5° 17:35	11.27	71%	36.3°
2030-01-14 Mon	28	—	unknown	18:55–23:40 (marginal, 4.75 h)	89.7° 17:30	11.25	80%	44.1°
2030-01-15 Tue	29	—	unknown	18:55–23:30 (marginal, 4.58 h)	89.7° 17:25	11.22	87%	53.2°
2030-01-16 Wed	33	—	unknown	18:55–23:30 (marginal, 4.58 h)	89.7° 17:20	11.2	93%	63.2°
2030-01-17 Thu	41	—	unknown	19:00–19:40 (good, 0.67 h)	89.5° 17:15	11.18	97%	73.9°
2030-01-18 Fri	53	—	unknown	19:00–20:55 (good, 1.92 h)	89.6° 17:15	11.16	99%	84.9°
2030-01-19 Sat	66	—	unknown	19:00–22:10 (good, 3.17 h)	89.7° 17:10	11.13	100%	96.2°
2030-01-20 Sun	79	—	unknown	19:00–22:50 (good, 3.83 h)	89.7° 17:05	11.11	98%	107.7°
2030-01-21 Mon	100	—	unknown	19:00–22:55 (good, 3.92 h)	89.6° 17:00	11.08	94%	119.1°
2030-01-22 Tue	100	—	unknown	19:05–22:55 (good, 3.83 h)	89.5° 16:55	11.05	88%	130.0°
2030-01-23 Wed	100	—	unknown	19:05–22:55 (good, 3.83 h)	89.6° 16:55	11.03	80%	140.0°
2030-01-24 Thu	100	—	unknown	19:05–23:00 (good, 3.92 h)	89.7° 16:50	11.0	70%	147.7°
2030-01-25 Fri	99	—	unknown	19:05–22:55 (good, 3.83 h)	89.7° 16:45	10.97	59%	151.0°
2030-01-26 Sat	97	—	unknown	19:10–22:50 (good, 3.67 h)	89.6° 16:40	10.94	48%	148.5°
2030-01-27 Sun	95	—	unknown	19:10–22:45 (good, 3.58 h)	89.5° 16:40	10.91	37%	141.1°
2030-01-28 Mon	93	—	unknown	19:10–22:45 (good, 3.58 h)	89.7° 16:35	10.88	26%	131.0°
2030-01-29 Tue	91	—	unknown	19:10–22:40 (good, 3.5 h)	89.7° 16:30	10.85	17%	119.6°
2030-01-30 Wed	89	—	unknown	19:10–22:35 (good, 3.42 h)	89.7° 16:25	10.82	9%	107.6°
2030-01-31 Thu	86	—	unknown	19:15–22:30 (good, 3.25 h)	89.5° 16:20	10.79	4%	95.4°
2030-02-01 Fri	83	—	unknown	19:15–22:25 (good, 3.17 h)	89.6° 16:20	10.76	1%	83.2°
2030-02-02 Sat	80	—	unknown	19:15–22:25 (good, 3.17 h)	89.7° 16:15	10.72	0%	71.4°
2030-02-03 Sun	78	—	unknown	19:15–22:20 (good, 3.08 h)	89.7° 16:10	10.69	2%	60.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-01-05&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.