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: 06-11 (31), 06-12 (31), 06-10 (30), 06-13 (29), 06-14 (29) — by astronomy; check the weather when the night is within four days.

2030-05-17astronomy score per night — click a bar for that night2030-06-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-05-17 Fri	5	—	unknown	03:45–04:05 (marginal, 0.33 h)	89.6° 10:20	5.47	100%	133.6°
2030-05-18 Sat	5	—	unknown	04:25–04:50 (marginal, 0.42 h)	89.5° 10:15	5.42	97%	121.7°
2030-05-19 Sun	5	—	unknown	03:35–04:00 (marginal, 0.42 h)	89.6° 10:15	5.37	91%	109.1°
2030-05-20 Mon	5	—	unknown	03:35–04:00 (marginal, 0.42 h)	89.7° 10:10	5.32	83%	96.5°
2030-05-21 Tue	5	—	unknown	03:30–04:00 (marginal, 0.5 h)	89.7° 10:05	5.27	74%	84.1°
2030-05-22 Wed	5	—	unknown	03:25–03:55 (marginal, 0.5 h)	89.6° 10:00	5.22	64%	72.2°
2030-05-23 Thu	6	—	unknown	03:20–03:55 (marginal, 0.58 h)	89.5° 10:00	5.17	53%	61.0°
2030-05-24 Fri	7	—	unknown	03:15–03:55 (marginal, 0.67 h)	89.7° 09:55	5.13	43%	50.7°
2030-05-25 Sat	8	—	unknown	03:15–03:55 (marginal, 0.67 h)	89.7° 09:50	5.08	33%	41.5°
2030-05-26 Sun	10	—	unknown	03:10–03:50 (marginal, 0.67 h)	89.7° 09:45	5.04	24%	34.2°
2030-05-27 Mon	12	—	unknown	03:45–03:50 (good, 0.08 h)	89.5° 09:40	4.99	16%	30.0°
2030-05-28 Tue	15	—	unknown	03:35–03:50 (good, 0.25 h)	89.6° 09:40	4.95	10%	29.8°
2030-05-29 Wed	16	—	unknown	03:30–03:50 (good, 0.33 h)	89.7° 09:35	4.91	5%	33.7°
2030-05-30 Thu	16	—	unknown	03:25–03:45 (good, 0.33 h)	89.7° 09:30	4.87	2%	40.5°
2030-05-31 Fri	17	—	unknown	03:25–03:45 (good, 0.33 h)	89.6° 09:25	4.83	0%	48.9°
2030-06-01 Sat	19	—	unknown	03:20–03:45 (good, 0.42 h)	89.5° 09:20	4.79	0%	58.3°
2030-06-02 Sun	21	—	unknown	03:15–03:45 (good, 0.5 h)	89.6° 09:20	4.76	2%	68.2°
2030-06-03 Mon	22	—	unknown	03:10–03:45 (good, 0.58 h)	89.7° 09:15	4.73	6%	78.6°
2030-06-04 Tue	23	—	unknown	03:05–03:45 (good, 0.67 h)	89.7° 09:10	4.69	12%	89.1°
2030-06-05 Wed	24	—	unknown	03:05–03:40 (good, 0.58 h)	89.6° 09:05	4.66	19%	99.8°
2030-06-06 Thu	25	—	unknown	03:00–03:40 (good, 0.67 h)	89.5° 09:05	4.63	28%	110.6°
2030-06-07 Fri	26	—	unknown	02:55–03:40 (good, 0.75 h)	89.7° 09:00	4.61	37%	121.3°
2030-06-08 Sat	27	—	unknown	02:50–03:40 (good, 0.83 h)	89.7° 08:55	4.58	48%	131.7°
2030-06-09 Sun	28	—	unknown	02:45–03:40 (good, 0.92 h)	89.7° 08:50	4.56	58%	141.1°
2030-06-10 Mon	30	—	unknown	02:45–03:40 (good, 0.92 h)	89.5° 08:45	4.53	69%	148.2°
2030-06-11 Tue	31	—	unknown	02:40–03:40 (good, 1.0 h)	89.6° 08:45	4.51	79%	150.7°
2030-06-12 Wed	31	—	unknown	02:45–03:40 (good, 0.92 h)	89.7° 08:40	4.5	88%	146.9°
2030-06-13 Thu	29	—	unknown	02:40–03:40 (good, 1.0 h)	89.7° 08:35	4.48	95%	138.4°
2030-06-14 Fri	29	—	unknown	02:40–03:40 (good, 1.0 h)	89.7° 08:30	4.46	99%	127.2°
2030-06-15 Sat	28	—	unknown	02:40–03:40 (good, 1.0 h)	89.5° 08:25	4.45	100%	114.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-05-17&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.