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: 06-18 (35), 06-17 (30), 06-16 (25), 06-04 (23), 06-03 (22) — by astronomy; check the weather when the night is within four days.

2047-05-20astronomy score per night — click a bar for that night2047-06-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-05-20 Mon	7	—	unknown	03:35–04:00 (marginal, 0.42 h)	89.8° 10:10	5.32	14%	30.0°
2047-05-21 Tue	8	—	unknown	03:30–04:00 (marginal, 0.5 h)	89.6° 10:05	5.27	8%	28.4°
2047-05-22 Wed	9	—	unknown	04:00–04:45 (marginal, 0.75 h)	89.6° 10:05	5.23	4%	31.0°
2047-05-23 Thu	10	—	unknown	03:20–04:45 (marginal, 1.42 h)	89.8° 10:00	5.18	1%	37.2°
2047-05-24 Fri	10	—	unknown	03:50–03:55 (good, 0.08 h)	89.8° 09:55	5.13	0%	45.4°
2047-05-25 Sat	11	—	unknown	03:45–03:55 (good, 0.17 h)	89.7° 09:50	5.09	1%	54.9°
2047-05-26 Sun	12	—	unknown	03:45–03:50 (good, 0.08 h)	89.5° 09:45	5.04	4%	65.2°
2047-05-27 Mon	13	—	unknown	03:40–03:50 (good, 0.17 h)	89.7° 09:45	5.0	9%	76.0°
2047-05-28 Tue	15	—	unknown	03:35–03:50 (good, 0.25 h)	89.8° 09:40	4.96	16%	87.0°
2047-05-29 Wed	15	—	unknown	03:30–03:50 (good, 0.33 h)	89.8° 09:35	4.91	24%	98.4°
2047-05-30 Thu	15	—	unknown	03:30–03:45 (good, 0.25 h)	89.7° 09:30	4.87	33%	109.8°
2047-05-31 Fri	17	—	unknown	03:25–03:45 (good, 0.33 h)	89.5° 09:30	4.84	44%	121.2°
2047-06-01 Sat	19	—	unknown	03:20–03:45 (good, 0.42 h)	89.7° 09:25	4.8	55%	132.3°
2047-06-02 Sun	20	—	unknown	03:15–03:45 (good, 0.5 h)	89.8° 09:20	4.76	66%	142.3°
2047-06-03 Mon	22	—	unknown	03:10–03:45 (good, 0.58 h)	89.8° 09:15	4.73	77%	149.6°
2047-06-04 Tue	23	—	unknown	03:15–03:45 (good, 0.5 h)	89.6° 09:10	4.7	86%	151.6°
2047-06-05 Wed	21	—	unknown	03:15–03:40 (good, 0.42 h)	89.6° 09:10	4.67	93%	147.0°
2047-06-06 Thu	21	—	unknown	03:10–03:40 (good, 0.5 h)	89.8° 09:05	4.64	98%	137.8°
2047-06-07 Fri	20	—	unknown	03:05–03:40 (good, 0.58 h)	89.8° 09:00	4.61	100%	126.4°
2047-06-08 Sat	20	—	unknown	03:05–03:40 (good, 0.58 h)	89.7° 08:55	4.58	99%	114.2°
2047-06-09 Sun	18	—	unknown	03:10–03:40 (good, 0.5 h)	89.5° 08:50	4.56	95%	101.7°
2047-06-10 Mon	17	—	unknown	03:15–03:40 (good, 0.42 h)	89.7° 08:50	4.54	90%	89.5°
2047-06-11 Tue	16	—	unknown	02:10–03:40 (marginal, 1.5 h)	89.8° 08:45	4.52	82%	77.6°
2047-06-12 Wed	16	—	unknown	02:05–03:40 (marginal, 1.58 h)	89.8° 08:40	4.5	73%	66.2°
2047-06-13 Thu	17	—	unknown	02:00–03:40 (marginal, 1.67 h)	89.7° 08:35	4.48	64%	55.6°
2047-06-14 Fri	19	—	unknown	03:00–03:40 (good, 0.67 h)	89.5° 08:35	4.47	54%	45.8°
2047-06-15 Sat	22	—	unknown	02:50–03:40 (good, 0.83 h)	89.7° 08:30	4.45	44%	37.4°
2047-06-16 Sun	25	—	unknown	02:40–03:40 (good, 1.0 h)	89.8° 08:25	4.44	35%	31.1°
2047-06-17 Mon	30	—	unknown	02:30–03:40 (good, 1.17 h)	89.8° 08:20	4.44	26%	28.3°
2047-06-18 Tue	35	—	unknown	02:15–03:40 (good, 1.42 h)	89.6° 08:15	4.43	18%	29.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-05-20&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.