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 (5), 03-12 (5), 03-13 (4), 03-14 (4), 03-15 (3) — by astronomy; check the weather when the night is within four days.

2036-03-11astronomy score per night — click a bar for that night2036-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-03-11 Tue	5	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.6° 13:45	9.15	100%	127.2°
2036-03-12 Wed	5	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.6° 13:45	9.1	100%	135.4°
2036-03-13 Thu	4	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.7° 13:40	9.05	97%	140.6°
2036-03-14 Fri	4	—	unknown	20:00–20:15 (marginal, 0.25 h)	89.8° 13:35	9.0	92%	142.0°
2036-03-15 Sat	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.7° 13:30	8.95	85%	139.4°
2036-03-16 Sun	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.5° 13:25	8.9	77%	133.8°
2036-03-17 Mon	1	—	unknown	—	89.6° 13:25	8.85	68%	126.4°
2036-03-18 Tue	1	—	unknown	—	89.7° 13:20	8.8	58%	118.0°
2036-03-19 Wed	1	—	unknown	—	89.8° 13:15	8.74	48%	109.1°
2036-03-20 Thu	1	—	unknown	—	89.6° 13:10	8.69	39%	99.9°
2036-03-21 Fri	0	—	unknown	—	89.5° 13:10	8.64	30%	90.6°
2036-03-22 Sat	0	—	unknown	—	89.7° 13:05	8.59	22%	81.3°
2036-03-23 Sun	0	—	unknown	—	89.8° 13:00	8.54	14%	72.1°
2036-03-24 Mon	0	—	unknown	—	89.7° 12:55	8.48	8%	63.1°
2036-03-25 Tue	0	—	unknown	—	89.6° 12:50	8.43	4%	54.5°
2036-03-26 Wed	0	—	unknown	—	89.5° 12:50	8.38	1%	47.0°
2036-03-27 Thu	0	—	unknown	—	89.7° 12:45	8.32	0%	41.1°
2036-03-28 Fri	0	—	unknown	—	89.8° 12:40	8.27	1%	38.1°
2036-03-29 Sat	0	—	unknown	—	89.7° 12:35	8.21	5%	38.7°
2036-03-30 Sun	0	—	unknown	—	89.5° 13:30	8.16	10%	43.1°
2036-03-31 Mon	0	—	unknown	—	89.6° 13:30	8.11	18%	50.2°
2036-04-01 Tue	0	—	unknown	—	89.7° 13:25	8.05	27%	59.2°
2036-04-02 Wed	0	—	unknown	—	89.8° 13:20	8.0	38%	69.4°
2036-04-03 Thu	0	—	unknown	—	89.6° 13:15	7.94	49%	80.2°
2036-04-04 Fri	0	—	unknown	—	89.5° 13:15	7.88	61%	91.4°
2036-04-05 Sat	0	—	unknown	—	89.7° 13:10	7.83	72%	102.6°
2036-04-06 Sun	0	—	unknown	—	89.8° 13:05	7.77	81%	113.4°
2036-04-07 Mon	0	—	unknown	—	89.7° 13:00	7.72	89%	123.6°
2036-04-08 Tue	0	—	unknown	—	89.6° 12:55	7.66	95%	132.4°
2036-04-09 Wed	0	—	unknown	—	89.5° 12:55	7.6	99%	138.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-03-11&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.