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 (7), 03-12 (6), 03-13 (6), 03-14 (5), 03-15 (3) — by astronomy; check the weather when the night is within four days.

2042-03-11astronomy score per night — click a bar for that night2042-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-03-11 Tue	7	—	unknown	19:25–20:30 (marginal, 1.08 h)	89.7° 13:50	9.17	78%	143.7°
2042-03-12 Wed	6	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.8° 13:45	9.12	70%	137.8°
2042-03-13 Thu	6	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.7° 13:40	9.07	60%	129.8°
2042-03-14 Fri	5	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.5° 13:35	9.02	50%	120.4°
2042-03-15 Sat	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.6° 13:35	8.97	40%	110.0°
2042-03-16 Sun	3	—	unknown	19:30–19:40 (marginal, 0.17 h)	89.8° 13:30	8.92	30%	98.8°
2042-03-17 Mon	2	—	unknown	19:30–19:35 (marginal, 0.08 h)	89.8° 13:25	8.87	20%	87.1°
2042-03-18 Tue	1	—	unknown	—	89.7° 13:20	8.82	11%	75.1°
2042-03-19 Wed	1	—	unknown	—	89.5° 13:20	8.77	5%	63.1°
2042-03-20 Thu	1	—	unknown	—	89.7° 13:15	8.72	1%	51.6°
2042-03-21 Fri	1	—	unknown	—	89.8° 13:10	8.66	0%	41.7°
2042-03-22 Sat	0	—	unknown	—	89.8° 13:05	8.61	2%	34.9°
2042-03-23 Sun	0	—	unknown	—	89.6° 13:00	8.56	7%	33.3°
2042-03-24 Mon	0	—	unknown	—	89.6° 13:00	8.51	15%	37.2°
2042-03-25 Tue	0	—	unknown	—	89.7° 12:55	8.45	24%	44.9°
2042-03-26 Wed	0	—	unknown	—	89.8° 12:50	8.4	34%	54.4°
2042-03-27 Thu	0	—	unknown	—	89.7° 12:45	8.35	44%	64.7°
2042-03-28 Fri	0	—	unknown	—	89.6° 12:40	8.29	55%	75.2°
2042-03-29 Sat	0	—	unknown	—	89.6° 12:40	8.24	64%	85.7°
2042-03-30 Sun	0	—	unknown	—	89.8° 13:35	8.18	74%	96.0°
2042-03-31 Mon	0	—	unknown	—	89.8° 13:30	8.13	82%	106.0°
2042-04-01 Tue	0	—	unknown	—	89.7° 13:25	8.08	88%	115.7°
2042-04-02 Wed	0	—	unknown	—	89.5° 13:20	8.02	94%	124.9°
2042-04-03 Thu	0	—	unknown	—	89.7° 13:20	7.97	98%	133.3°
2042-04-04 Fri	0	—	unknown	—	89.8° 13:15	7.91	100%	140.3°
2042-04-05 Sat	0	—	unknown	—	89.8° 13:10	7.85	100%	145.2°
2042-04-06 Sun	0	—	unknown	—	89.6° 13:05	7.8	98%	146.9°
2042-04-07 Mon	0	—	unknown	—	89.5° 13:05	7.74	95%	144.9°
2042-04-08 Tue	0	—	unknown	—	89.7° 13:00	7.69	90%	139.6°
2042-04-09 Wed	0	—	unknown	—	89.8° 12:55	7.63	83%	132.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-03-11&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.