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 (5), 03-13 (4), 03-14 (3), 03-15 (2) — by astronomy; check the weather when the night is within four days.

2027-03-11astronomy score per night — click a bar for that night2027-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-03-11 Thu	6	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.7° 13:50	9.19	13%	28.8°
2027-03-12 Fri	5	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.7° 13:45	9.14	21%	33.3°
2027-03-13 Sat	4	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.6° 13:40	9.09	31%	41.5°
2027-03-14 Sun	3	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.5° 13:40	9.04	42%	51.8°
2027-03-15 Mon	2	—	unknown	20:00–20:10 (marginal, 0.17 h)	89.7° 13:35	8.99	53%	63.3°
2027-03-16 Tue	1	—	unknown	—	89.7° 13:30	8.94	64%	75.5°
2027-03-17 Wed	1	—	unknown	—	89.7° 13:25	8.89	75%	88.1°
2027-03-18 Thu	1	—	unknown	—	89.5° 13:20	8.84	84%	100.7°
2027-03-19 Fri	1	—	unknown	—	89.6° 13:20	8.79	92%	113.3°
2027-03-20 Sat	1	—	unknown	—	89.7° 13:15	8.73	97%	125.4°
2027-03-21 Sun	0	—	unknown	—	89.7° 13:10	8.68	100%	136.4°
2027-03-22 Mon	0	—	unknown	—	89.6° 13:05	8.63	100%	145.4°
2027-03-23 Tue	0	—	unknown	—	89.5° 13:00	8.58	97%	150.8°
2027-03-24 Wed	0	—	unknown	—	89.6° 13:00	8.53	92%	150.7°
2027-03-25 Thu	0	—	unknown	—	89.7° 12:55	8.47	86%	145.8°
2027-03-26 Fri	0	—	unknown	—	89.7° 12:50	8.42	78%	137.9°
2027-03-27 Sat	0	—	unknown	—	89.6° 12:45	8.37	70%	128.6°
2027-03-28 Sun	0	—	unknown	—	89.5° 13:45	8.31	60%	118.7°
2027-03-29 Mon	0	—	unknown	—	89.6° 13:40	8.26	51%	108.5°
2027-03-30 Tue	0	—	unknown	—	89.7° 13:35	8.2	42%	98.2°
2027-03-31 Wed	0	—	unknown	—	89.7° 13:30	8.15	32%	87.8°
2027-04-01 Thu	0	—	unknown	—	89.5° 13:25	8.1	24%	77.4°
2027-04-02 Fri	0	—	unknown	—	89.6° 13:25	8.04	16%	66.9°
2027-04-03 Sat	0	—	unknown	—	89.7° 13:20	7.99	10%	56.6°
2027-04-04 Sun	0	—	unknown	—	89.7° 13:15	7.93	5%	46.7°
2027-04-05 Mon	0	—	unknown	—	89.6° 13:10	7.87	1%	37.8°
2027-04-06 Tue	0	—	unknown	—	89.5° 13:05	7.82	0%	31.1°
2027-04-07 Wed	0	—	unknown	—	89.6° 13:05	7.76	1%	28.6°
2027-04-08 Thu	0	—	unknown	—	89.7° 13:00	7.71	5%	31.7°
2027-04-09 Fri	0	—	unknown	—	89.7° 12:55	7.65	10%	39.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-03-11&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.