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: 05-05 (2), 05-06 (2), 05-07 (2), 05-08 (2), 05-09 (2) — by astronomy; check the weather when the night is within four days.

2046-04-10astronomy score per night — click a bar for that night2046-05-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-04-10 Tue	0	—	unknown	—	89.7° 12:50	7.57	18%	50.2°
2046-04-11 Wed	0	—	unknown	—	89.6° 12:45	7.51	27%	60.8°
2046-04-12 Thu	0	—	unknown	—	89.6° 12:45	7.46	37%	72.0°
2046-04-13 Fri	0	—	unknown	—	89.8° 12:40	7.4	48%	83.8°
2046-04-14 Sat	0	—	unknown	—	89.8° 12:35	7.34	59%	95.9°
2046-04-15 Sun	0	—	unknown	—	89.7° 12:30	7.28	70%	108.3°
2046-04-16 Mon	0	—	unknown	—	89.5° 12:30	7.23	80%	120.6°
2046-04-17 Tue	0	—	unknown	—	89.7° 12:25	7.17	88%	132.5°
2046-04-18 Wed	0	—	unknown	—	89.8° 12:20	7.11	95%	142.9°
2046-04-19 Thu	0	—	unknown	—	89.8° 12:15	7.05	99%	150.0°
2046-04-20 Fri	0	—	unknown	—	89.6° 12:10	6.99	100%	151.2°
2046-04-21 Sat	0	—	unknown	—	89.6° 12:10	6.94	98%	146.0°
2046-04-22 Sun	0	—	unknown	—	89.8° 12:00	6.88	94%	137.0°
2046-04-23 Mon	0	—	unknown	—	89.8° 12:00	6.82	87%	126.4°
2046-04-24 Tue	0	—	unknown	—	89.6° 11:50	6.76	79%	115.2°
2046-04-25 Wed	0	—	unknown	—	89.6° 11:50	6.7	70%	104.1°
2046-04-26 Thu	0	—	unknown	—	89.8° 11:45	6.64	60%	93.0°
2046-04-27 Fri	0	—	unknown	—	89.8° 11:40	6.59	50%	82.3°
2046-04-28 Sat	1	—	unknown	—	89.7° 11:35	6.53	41%	71.8°
2046-04-29 Sun	1	—	unknown	—	89.5° 11:30	6.47	32%	61.6°
2046-04-30 Mon	1	—	unknown	—	89.7° 11:30	6.41	23%	51.9°
2046-05-01 Tue	1	—	unknown	—	89.8° 11:25	6.35	16%	42.9°
2046-05-02 Wed	1	—	unknown	—	89.8° 11:20	6.3	10%	35.2°
2046-05-03 Thu	1	—	unknown	—	89.6° 11:15	6.24	5%	29.9°
2046-05-04 Fri	1	—	unknown	—	89.6° 11:15	6.18	2%	28.5°
2046-05-05 Sat	2	—	unknown	—	89.7° 11:10	6.12	0%	31.8°
2046-05-06 Sun	2	—	unknown	05:00–05:05 (marginal, 0.08 h)	89.8° 11:05	6.07	1%	38.8°
2046-05-07 Mon	2	—	unknown	04:55–05:00 (marginal, 0.08 h)	89.7° 11:00	6.01	4%	47.9°
2046-05-08 Tue	2	—	unknown	04:55–05:00 (marginal, 0.08 h)	89.6° 10:55	5.95	8%	58.3°
2046-05-09 Wed	2	—	unknown	04:50–05:00 (marginal, 0.17 h)	89.6° 10:55	5.9	15%	69.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-04-10&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.