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: 08-01 (100), 08-02 (100), 08-03 (100), 08-04 (100), 08-05 (100) — by astronomy; check the weather when the night is within four days.

2043-07-18astronomy score per night — click a bar for that night2043-08-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-07-18 Sat	99	—	unknown	00:25–04:05 (good, 3.67 h)	89.7° 06:20	5.13	90%	124.3°
2043-07-19 Sun	96	—	unknown	00:25–04:05 (good, 3.67 h)	89.8° 06:15	5.17	95%	114.6°
2043-07-20 Mon	77	—	unknown	00:30–04:05 (good, 3.58 h)	89.7° 06:10	5.22	98%	104.2°
2043-07-21 Tue	67	—	unknown	00:35–04:10 (good, 3.58 h)	89.6° 06:05	5.27	100%	93.5°
2043-07-22 Wed	56	—	unknown	01:20–04:10 (good, 2.83 h)	89.6° 06:05	5.32	99%	82.6°
2043-07-23 Thu	47	—	unknown	02:35–04:10 (good, 1.58 h)	89.8° 06:00	5.37	96%	71.5°
2043-07-24 Fri	41	—	unknown	23:25–04:15 (marginal, 4.83 h)	89.8° 05:55	5.42	92%	60.6°
2043-07-25 Sat	38	—	unknown	23:20–04:15 (marginal, 4.92 h)	89.7° 05:50	5.47	85%	50.1°
2043-07-26 Sun	39	—	unknown	23:10–04:15 (marginal, 5.08 h)	89.5° 05:45	5.52	76%	40.8°
2043-07-27 Mon	47	—	unknown	23:05–04:15 (marginal, 5.17 h)	89.7° 05:45	5.57	66%	33.8°
2043-07-28 Tue	67	—	unknown	23:35–04:20 (good, 4.75 h)	89.8° 05:40	5.62	55%	30.9°
2043-07-29 Wed	83	—	unknown	23:30–04:20 (good, 4.83 h)	89.8° 05:35	5.68	43%	33.6°
2043-07-30 Thu	87	—	unknown	23:30–04:20 (good, 4.83 h)	89.6° 05:30	5.73	32%	40.8°
2043-07-31 Fri	93	—	unknown	23:25–04:25 (good, 5.0 h)	89.5° 05:30	5.79	22%	50.8°
2043-08-01 Sat	100	—	unknown	23:20–04:25 (good, 5.08 h)	89.7° 05:25	5.84	13%	62.1°
2043-08-02 Sun	100	—	unknown	23:15–04:25 (good, 5.17 h)	89.8° 05:20	5.9	6%	74.0°
2043-08-03 Mon	100	—	unknown	23:10–04:30 (good, 5.33 h)	89.7° 05:15	5.95	2%	86.1°
2043-08-04 Tue	100	—	unknown	23:10–04:30 (good, 5.33 h)	89.6° 05:10	6.01	0%	98.2°
2043-08-05 Wed	100	—	unknown	23:05–04:30 (good, 5.42 h)	89.6° 05:10	6.06	1%	109.9°
2043-08-06 Thu	100	—	unknown	23:00–04:35 (good, 5.58 h)	89.8° 05:05	6.12	4%	120.9°
2043-08-07 Fri	100	—	unknown	22:55–04:35 (good, 5.67 h)	89.8° 05:00	6.18	9%	131.0°
2043-08-08 Sat	100	—	unknown	22:50–04:35 (good, 5.75 h)	89.7° 04:55	6.23	16%	139.7°
2043-08-09 Sun	100	—	unknown	22:50–04:40 (good, 5.83 h)	89.5° 04:50	6.29	24%	146.1°
2043-08-10 Mon	100	—	unknown	22:45–04:40 (good, 5.92 h)	89.7° 04:50	6.35	33%	149.1°
2043-08-11 Tue	100	—	unknown	22:45–04:40 (good, 5.92 h)	89.8° 04:45	6.41	42%	147.9°
2043-08-12 Wed	100	—	unknown	22:40–04:45 (good, 6.08 h)	89.8° 04:40	6.46	51%	143.2°
2043-08-13 Thu	100	—	unknown	22:40–04:45 (good, 6.08 h)	89.6° 04:35	6.52	61%	136.1°
2043-08-14 Fri	100	—	unknown	22:35–04:45 (good, 6.17 h)	89.5° 04:35	6.58	70%	127.5°
2043-08-15 Sat	100	—	unknown	22:35–04:45 (good, 6.17 h)	89.7° 04:30	6.64	78%	118.0°
2043-08-16 Sun	100	—	unknown	22:35–04:50 (good, 6.25 h)	89.8° 04:25	6.69	86%	107.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-07-18&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.