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: 04-26 (1), 04-27 (1), 04-28 (1), 04-29 (1), 04-30 (1) — by astronomy; check the weather when the night is within four days.

2040-04-01astronomy score per night — click a bar for that night2040-04-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-04-01 Sun	0	—	unknown	—	89.8° 13:25	8.05	79%	129.9°
2040-04-02 Mon	0	—	unknown	—	89.8° 13:20	7.99	68%	120.2°
2040-04-03 Tue	0	—	unknown	—	89.6° 13:15	7.94	57%	109.5°
2040-04-04 Wed	0	—	unknown	—	89.5° 13:15	7.88	46%	98.3°
2040-04-05 Thu	0	—	unknown	—	89.7° 13:10	7.83	35%	87.0°
2040-04-06 Fri	0	—	unknown	—	89.8° 13:05	7.77	24%	75.7°
2040-04-07 Sat	0	—	unknown	—	89.7° 13:00	7.72	16%	64.9°
2040-04-08 Sun	0	—	unknown	—	89.6° 12:55	7.66	8%	54.8°
2040-04-09 Mon	0	—	unknown	—	89.6° 12:55	7.6	3%	46.1°
2040-04-10 Tue	0	—	unknown	—	89.7° 12:50	7.55	1%	39.7°
2040-04-11 Wed	0	—	unknown	—	89.8° 12:45	7.49	0%	36.5°
2040-04-12 Thu	0	—	unknown	—	89.7° 12:40	7.43	2%	37.2°
2040-04-13 Fri	0	—	unknown	—	89.5° 12:35	7.37	6%	41.4°
2040-04-14 Sat	0	—	unknown	—	89.6° 12:35	7.32	11%	48.1°
2040-04-15 Sun	0	—	unknown	—	89.8° 12:30	7.26	18%	56.1°
2040-04-16 Mon	0	—	unknown	—	89.8° 12:25	7.2	26%	64.8°
2040-04-17 Tue	0	—	unknown	—	89.7° 12:20	7.14	35%	74.0°
2040-04-18 Wed	0	—	unknown	—	89.5° 12:20	7.08	44%	83.4°
2040-04-19 Thu	0	—	unknown	—	89.7° 12:15	7.03	54%	93.0°
2040-04-20 Fri	0	—	unknown	—	89.8° 12:10	6.97	63%	102.6°
2040-04-21 Sat	0	—	unknown	—	89.7° 12:05	6.91	72%	112.2°
2040-04-22 Sun	0	—	unknown	—	89.6° 12:00	6.85	81%	121.5°
2040-04-23 Mon	0	—	unknown	—	89.7° 11:55	6.79	88%	130.2°
2040-04-24 Tue	0	—	unknown	—	89.8° 11:50	6.74	94%	137.6°
2040-04-25 Wed	0	—	unknown	—	89.7° 11:45	6.68	98%	142.5°
2040-04-26 Thu	1	—	unknown	—	89.5° 11:40	6.62	100%	143.5°
2040-04-27 Fri	1	—	unknown	—	89.6° 11:40	6.56	99%	140.0°
2040-04-28 Sat	1	—	unknown	—	89.8° 11:35	6.5	96%	132.7°
2040-04-29 Sun	1	—	unknown	—	89.8° 11:30	6.44	90%	123.2°
2040-04-30 Mon	1	—	unknown	—	89.7° 11:25	6.39	81%	112.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-04-01&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.