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: 05-08 (2), 05-09 (2), 05-10 (2), 05-11 (2), 04-26 (1) — by astronomy; check the weather when the night is within four days.

2042-04-12astronomy score per night — click a bar for that night2042-05-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-04-12 Sat	0	—	unknown	—	89.6° 12:45	7.46	56%	102.3°
2042-04-13 Sun	0	—	unknown	—	89.8° 12:40	7.4	45%	91.2°
2042-04-14 Mon	0	—	unknown	—	89.8° 12:35	7.34	34%	79.6°
2042-04-15 Tue	0	—	unknown	—	89.7° 12:30	7.29	24%	68.0°
2042-04-16 Wed	0	—	unknown	—	89.5° 12:25	7.23	14%	56.5°
2042-04-17 Thu	0	—	unknown	—	89.7° 12:25	7.17	7%	45.9°
2042-04-18 Fri	0	—	unknown	—	89.8° 12:20	7.11	2%	37.5°
2042-04-19 Sat	0	—	unknown	—	89.8° 12:15	7.05	0%	33.3°
2042-04-20 Sun	0	—	unknown	—	89.6° 12:10	7.0	1%	34.8°
2042-04-21 Mon	0	—	unknown	—	89.5° 12:10	6.94	5%	41.2°
2042-04-22 Tue	0	—	unknown	—	89.8° 12:00	6.88	11%	50.4°
2042-04-23 Wed	0	—	unknown	—	89.8° 12:00	6.82	19%	60.8°
2042-04-24 Thu	0	—	unknown	—	89.6° 11:50	6.76	28%	71.6°
2042-04-25 Fri	0	—	unknown	—	89.6° 11:50	6.71	38%	82.4°
2042-04-26 Sat	1	—	unknown	—	89.8° 11:45	6.65	48%	93.0°
2042-04-27 Sun	1	—	unknown	—	89.8° 11:40	6.59	58%	103.2°
2042-04-28 Mon	1	—	unknown	—	89.7° 11:35	6.53	68%	113.1°
2042-04-29 Tue	1	—	unknown	—	89.5° 11:30	6.47	76%	122.5°
2042-04-30 Wed	1	—	unknown	—	89.7° 11:30	6.41	84%	131.1°
2042-05-01 Thu	1	—	unknown	—	89.8° 11:25	6.36	90%	138.6°
2042-05-02 Fri	1	—	unknown	—	89.8° 11:20	6.3	95%	144.2°
2042-05-03 Sat	1	—	unknown	—	89.6° 11:15	6.24	98%	146.8°
2042-05-04 Sun	1	—	unknown	—	89.5° 11:15	6.18	100%	145.8°
2042-05-05 Mon	1	—	unknown	—	89.7° 11:10	6.13	100%	141.2°
2042-05-06 Tue	1	—	unknown	—	89.8° 11:05	6.07	97%	134.0°
2042-05-07 Wed	1	—	unknown	—	89.7° 11:00	6.01	93%	125.2°
2042-05-08 Thu	2	—	unknown	—	89.6° 10:55	5.96	87%	115.4°
2042-05-09 Fri	2	—	unknown	—	89.6° 10:55	5.9	79%	104.9°
2042-05-10 Sat	2	—	unknown	04:10–04:15 (marginal, 0.08 h)	89.8° 10:50	5.84	70%	93.9°
2042-05-11 Sun	2	—	unknown	04:10–04:15 (marginal, 0.08 h)	89.8° 10:45	5.79	60%	82.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-04-12&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.