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: 07-18 (100), 07-19 (100), 07-20 (100), 07-21 (100), 07-22 (100) — by astronomy; check the weather when the night is within four days.

2039-07-09astronomy score per night — click a bar for that night2039-08-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-07-09 Sat	35	—	unknown	03:15–03:50 (good, 0.58 h)	89.7° 06:55	4.76	81%	60.0°
2039-07-10 Sun	37	—	unknown	02:35–03:55 (good, 1.33 h)	89.8° 06:50	4.79	72%	51.1°
2039-07-11 Mon	43	—	unknown	01:10–03:55 (good, 2.75 h)	89.7° 06:45	4.83	62%	43.9°
2039-07-12 Tue	56	—	unknown	00:40–03:55 (good, 3.25 h)	89.5° 06:40	4.87	52%	39.2°
2039-07-13 Wed	65	—	unknown	00:35–03:55 (good, 3.33 h)	89.6° 06:40	4.91	42%	37.5°
2039-07-14 Thu	74	—	unknown	00:30–04:00 (good, 3.5 h)	89.8° 06:35	4.95	33%	39.1°
2039-07-15 Fri	82	—	unknown	00:25–04:00 (good, 3.58 h)	89.8° 06:30	4.99	24%	43.5°
2039-07-16 Sat	90	—	unknown	00:25–04:00 (good, 3.58 h)	89.6° 06:25	5.03	17%	49.9°
2039-07-17 Sun	98	—	unknown	00:20–04:00 (good, 3.67 h)	89.5° 06:25	5.08	10%	57.6°
2039-07-18 Mon	100	—	unknown	00:15–04:05 (good, 3.83 h)	89.7° 06:20	5.12	5%	66.2°
2039-07-19 Tue	100	—	unknown	00:10–04:05 (good, 3.92 h)	89.8° 06:15	5.17	2%	75.4°
2039-07-20 Wed	100	—	unknown	00:05–04:05 (good, 4.0 h)	89.7° 06:10	5.22	0%	85.0°
2039-07-21 Thu	100	—	unknown	00:05–04:10 (good, 4.08 h)	89.6° 06:05	5.27	0%	94.7°
2039-07-22 Fri	100	—	unknown	00:00–04:10 (good, 4.17 h)	89.6° 06:05	5.31	3%	104.6°
2039-07-23 Sat	100	—	unknown	23:55–04:10 (good, 4.25 h)	89.7° 06:00	5.36	7%	114.3°
2039-07-24 Sun	100	—	unknown	23:50–04:15 (good, 4.42 h)	89.8° 05:55	5.41	13%	123.5°
2039-07-25 Mon	100	—	unknown	23:45–04:15 (good, 4.5 h)	89.7° 05:50	5.47	21%	131.9°
2039-07-26 Tue	100	—	unknown	23:45–04:15 (good, 4.5 h)	89.5° 05:45	5.52	30%	138.5°
2039-07-27 Wed	100	—	unknown	23:45–04:15 (good, 4.5 h)	89.6° 05:45	5.57	41%	142.2°
2039-07-28 Thu	100	—	unknown	23:40–04:20 (good, 4.67 h)	89.8° 05:40	5.62	52%	141.8°
2039-07-29 Fri	100	—	unknown	23:40–04:20 (good, 4.67 h)	89.8° 05:35	5.68	64%	137.4°
2039-07-30 Sat	100	—	unknown	23:35–04:20 (good, 4.75 h)	89.6° 05:30	5.73	74%	129.7°
2039-07-31 Sun	100	—	unknown	23:35–04:25 (good, 4.83 h)	89.5° 05:30	5.78	84%	119.9°
2039-08-01 Mon	100	—	unknown	23:35–04:25 (good, 4.83 h)	89.7° 05:25	5.84	92%	109.1°
2039-08-02 Tue	84	—	unknown	23:40–04:25 (good, 4.75 h)	89.8° 05:20	5.89	97%	97.6°
2039-08-03 Wed	76	—	unknown	00:15–04:30 (good, 4.25 h)	89.7° 05:15	5.95	100%	86.0°
2039-08-04 Thu	63	—	unknown	01:30–04:30 (good, 3.0 h)	89.6° 05:10	6.01	100%	74.7°
2039-08-05 Fri	52	—	unknown	22:35–04:30 (marginal, 5.92 h)	89.6° 05:10	6.06	97%	64.0°
2039-08-06 Sat	46	—	unknown	22:30–04:35 (marginal, 6.08 h)	89.7° 05:05	6.12	92%	54.3°
2039-08-07 Sun	46	—	unknown	22:25–04:35 (marginal, 6.17 h)	89.8° 05:00	6.18	85%	46.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-07-09&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.