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: 03-11 (6), 03-12 (6), 03-13 (5), 03-14 (4), 03-15 (3) — by astronomy; check the weather when the night is within four days.

2028-03-11astronomy score per night — click a bar for that night2028-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-03-11 Sat	6	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.6° 13:45	9.15	99%	144.0°
2028-03-12 Sun	6	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.5° 13:45	9.1	95%	150.6°
2028-03-13 Mon	5	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.7° 13:40	9.05	88%	151.2°
2028-03-14 Tue	4	—	unknown	20:00–20:15 (marginal, 0.25 h)	89.7° 13:35	9.0	80%	145.9°
2028-03-15 Wed	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.7° 13:30	8.95	70%	137.3°
2028-03-16 Thu	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.5° 13:25	8.9	60%	127.2°
2028-03-17 Fri	1	—	unknown	—	89.6° 13:25	8.85	50%	116.7°
2028-03-18 Sat	1	—	unknown	—	89.7° 13:20	8.8	41%	106.1°
2028-03-19 Sun	1	—	unknown	—	89.7° 13:15	8.75	31%	95.5°
2028-03-20 Mon	1	—	unknown	—	89.6° 13:10	8.7	23%	85.0°
2028-03-21 Tue	0	—	unknown	—	89.5° 13:05	8.64	16%	74.6°
2028-03-22 Wed	0	—	unknown	—	89.6° 13:05	8.59	9%	64.4°
2028-03-23 Thu	0	—	unknown	—	89.7° 13:00	8.54	5%	54.5°
2028-03-24 Fri	0	—	unknown	—	89.7° 12:55	8.49	2%	45.2°
2028-03-25 Sat	0	—	unknown	—	89.6° 12:50	8.43	0%	37.0°
2028-03-26 Sun	0	—	unknown	—	89.5° 13:50	8.38	1%	30.8°
2028-03-27 Mon	0	—	unknown	—	89.6° 13:45	8.33	3%	28.3°
2028-03-28 Tue	0	—	unknown	—	89.7° 13:40	8.27	7%	30.5°
2028-03-29 Wed	0	—	unknown	—	89.7° 13:35	8.22	13%	36.8°
2028-03-30 Thu	0	—	unknown	—	89.5° 13:30	8.16	21%	45.6°
2028-03-31 Fri	0	—	unknown	—	89.5° 13:30	8.11	30%	55.9°
2028-04-01 Sat	0	—	unknown	—	89.7° 13:25	8.05	40%	67.1°
2028-04-02 Sun	0	—	unknown	—	89.7° 13:20	8.0	51%	78.9°
2028-04-03 Mon	0	—	unknown	—	89.6° 13:15	7.94	63%	91.2°
2028-04-04 Tue	0	—	unknown	—	89.5° 13:10	7.89	73%	103.7°
2028-04-05 Wed	0	—	unknown	—	89.6° 13:10	7.83	83%	116.3°
2028-04-06 Thu	0	—	unknown	—	89.7° 13:05	7.78	91%	128.5°
2028-04-07 Fri	0	—	unknown	—	89.7° 13:00	7.72	97%	139.6°
2028-04-08 Sat	0	—	unknown	—	89.6° 12:55	7.66	100%	148.2°
2028-04-09 Sun	0	—	unknown	—	89.5° 12:55	7.61	100%	151.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-03-11&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.