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: 06-09 (28), 06-08 (27), 06-07 (26), 06-06 (25), 06-05 (24) — by astronomy; check the weather when the night is within four days.

2041-05-11astronomy score per night — click a bar for that night2041-06-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-05-11 Sat	3	—	unknown	04:40–04:55 (marginal, 0.25 h)	89.8° 10:45	5.77	83%	136.3°
2041-05-12 Sun	3	—	unknown	04:45–04:55 (marginal, 0.17 h)	89.8° 10:40	5.72	90%	142.2°
2041-05-13 Mon	4	—	unknown	04:40–04:55 (marginal, 0.25 h)	89.7° 10:35	5.67	95%	145.1°
2041-05-14 Tue	4	—	unknown	03:55–04:10 (marginal, 0.25 h)	89.5° 10:30	5.61	99%	144.1°
2041-05-15 Wed	4	—	unknown	03:50–04:05 (marginal, 0.25 h)	89.7° 10:30	5.56	100%	139.2°
2041-05-16 Thu	4	—	unknown	04:30–04:50 (marginal, 0.33 h)	89.8° 10:25	5.51	99%	131.4°
2041-05-17 Fri	5	—	unknown	03:45–04:05 (marginal, 0.33 h)	89.8° 10:20	5.45	96%	121.8°
2041-05-18 Sat	5	—	unknown	03:40–04:00 (marginal, 0.33 h)	89.6° 10:15	5.4	90%	111.0°
2041-05-19 Sun	5	—	unknown	03:35–04:00 (marginal, 0.42 h)	89.5° 10:15	5.35	82%	99.7°
2041-05-20 Mon	5	—	unknown	03:30–04:00 (marginal, 0.5 h)	89.7° 10:10	5.3	72%	88.1°
2041-05-21 Tue	6	—	unknown	03:30–04:00 (marginal, 0.5 h)	89.8° 10:05	5.25	62%	76.5°
2041-05-22 Wed	6	—	unknown	03:25–03:55 (marginal, 0.5 h)	89.7° 10:00	5.2	50%	65.2°
2041-05-23 Thu	7	—	unknown	03:20–03:55 (marginal, 0.58 h)	89.6° 09:55	5.16	39%	54.6°
2041-05-24 Fri	9	—	unknown	03:15–03:55 (marginal, 0.67 h)	89.6° 09:55	5.11	28%	45.2°
2041-05-25 Sat	11	—	unknown	03:45–03:50 (good, 0.08 h)	89.7° 09:50	5.07	18%	38.2°
2041-05-26 Sun	12	—	unknown	03:40–03:50 (good, 0.17 h)	89.8° 09:45	5.02	10%	34.9°
2041-05-27 Mon	14	—	unknown	03:35–03:50 (good, 0.25 h)	89.7° 09:40	4.98	5%	36.2°
2041-05-28 Tue	15	—	unknown	03:35–03:50 (good, 0.25 h)	89.5° 09:35	4.94	1%	41.4°
2041-05-29 Wed	16	—	unknown	03:30–03:50 (good, 0.33 h)	89.6° 09:35	4.9	0%	49.3°
2041-05-30 Thu	17	—	unknown	03:25–03:45 (good, 0.33 h)	89.8° 09:30	4.86	1%	58.4°
2041-05-31 Fri	18	—	unknown	03:20–03:45 (good, 0.42 h)	89.8° 09:25	4.82	4%	68.2°
2041-06-01 Sat	19	—	unknown	03:20–03:45 (good, 0.42 h)	89.6° 09:20	4.78	9%	78.2°
2041-06-02 Sun	21	—	unknown	03:15–03:45 (good, 0.5 h)	89.5° 09:20	4.75	16%	88.3°
2041-06-03 Mon	23	—	unknown	03:10–03:45 (good, 0.58 h)	89.7° 09:15	4.71	23%	98.1°
2041-06-04 Tue	23	—	unknown	03:05–03:40 (good, 0.58 h)	89.8° 09:10	4.68	32%	107.8°
2041-06-05 Wed	24	—	unknown	03:00–03:40 (good, 0.67 h)	89.7° 09:05	4.65	41%	117.1°
2041-06-06 Thu	25	—	unknown	03:00–03:40 (good, 0.67 h)	89.6° 09:00	4.62	50%	125.9°
2041-06-07 Fri	26	—	unknown	02:55–03:40 (good, 0.75 h)	89.6° 09:00	4.6	60%	133.9°
2041-06-08 Sat	27	—	unknown	02:50–03:40 (good, 0.83 h)	89.7° 08:55	4.57	69%	140.4°
2041-06-09 Sun	28	—	unknown	02:55–03:40 (good, 0.75 h)	89.8° 08:50	4.55	78%	144.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-05-11&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.