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: 07-10 (82), 07-11 (82), 07-09 (79), 07-08 (78), 07-07 (77) — by astronomy; check the weather when the night is within four days.

2041-06-20astronomy score per night — click a bar for that night2041-07-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-06-20 Thu	27	—	unknown	02:25–03:40 (good, 1.25 h)	89.6° 08:05	4.42	52%	47.0°
2041-06-21 Fri	31	—	unknown	02:15–03:40 (good, 1.42 h)	89.6° 08:05	4.42	41%	39.4°
2041-06-22 Sat	39	—	unknown	01:55–03:40 (good, 1.75 h)	89.7° 08:00	4.43	30%	35.2°
2041-06-23 Sun	44	—	unknown	01:50–03:40 (good, 1.83 h)	89.8° 07:55	4.43	21%	35.3°
2041-06-24 Mon	49	—	unknown	01:45–03:40 (good, 1.92 h)	89.7° 07:50	4.44	13%	39.7°
2041-06-25 Tue	53	—	unknown	01:45–03:40 (good, 1.92 h)	89.5° 07:45	4.45	7%	46.9°
2041-06-26 Wed	55	—	unknown	01:40–03:40 (good, 2.0 h)	89.6° 07:45	4.46	2%	55.6°
2041-06-27 Thu	56	—	unknown	01:35–03:40 (good, 2.08 h)	89.8° 07:40	4.47	0%	65.2°
2041-06-28 Fri	58	—	unknown	01:30–03:40 (good, 2.17 h)	89.8° 07:35	4.49	0%	75.1°
2041-06-29 Sat	60	—	unknown	01:30–03:40 (good, 2.17 h)	89.6° 07:30	4.5	2%	85.2°
2041-06-30 Sun	63	—	unknown	01:25–03:45 (good, 2.33 h)	89.5° 07:30	4.52	6%	95.1°
2041-07-01 Mon	65	—	unknown	01:20–03:45 (good, 2.42 h)	89.7° 07:25	4.55	11%	104.9°
2041-07-02 Tue	66	—	unknown	01:15–03:45 (good, 2.5 h)	89.8° 07:20	4.57	18%	114.4°
2041-07-03 Wed	68	—	unknown	01:10–03:45 (good, 2.58 h)	89.7° 07:15	4.59	26%	123.4°
2041-07-04 Thu	71	—	unknown	01:10–03:45 (good, 2.58 h)	89.6° 07:10	4.62	34%	131.6°
2041-07-05 Fri	74	—	unknown	01:05–03:50 (good, 2.75 h)	89.6° 07:10	4.65	44%	138.6°
2041-07-06 Sat	76	—	unknown	01:05–03:50 (good, 2.75 h)	89.7° 07:05	4.68	53%	143.6°
2041-07-07 Sun	77	—	unknown	01:00–03:50 (good, 2.83 h)	89.8° 07:00	4.71	63%	145.4°
2041-07-08 Mon	78	—	unknown	01:00–03:50 (good, 2.83 h)	89.7° 06:55	4.74	73%	143.4°
2041-07-09 Tue	79	—	unknown	00:55–03:50 (good, 2.92 h)	89.5° 06:50	4.78	82%	137.7°
2041-07-10 Wed	82	—	unknown	00:55–03:55 (good, 3.0 h)	89.6° 06:50	4.81	89%	129.4°
2041-07-11 Thu	82	—	unknown	00:50–03:55 (good, 3.08 h)	89.8° 06:45	4.85	95%	119.2°
2041-07-12 Fri	66	—	unknown	00:55–03:55 (good, 3.0 h)	89.8° 06:40	4.89	99%	107.9°
2041-07-13 Sat	57	—	unknown	01:00–03:55 (good, 2.92 h)	89.7° 06:35	4.93	100%	95.9°
2041-07-14 Sun	49	—	unknown	01:35–04:00 (good, 2.42 h)	89.5° 06:35	4.97	98%	83.7°
2041-07-15 Mon	43	—	unknown	02:40–04:00 (good, 1.33 h)	89.7° 06:30	5.01	93%	71.5°
2041-07-16 Tue	38	—	unknown	03:35–04:00 (good, 0.42 h)	89.8° 06:25	5.06	86%	59.9°
2041-07-17 Wed	39	—	unknown	23:45–04:05 (marginal, 4.33 h)	89.8° 06:20	5.1	77%	49.4°
2041-07-18 Thu	44	—	unknown	01:55–04:05 (good, 2.17 h)	89.6° 06:15	5.15	66%	40.8°
2041-07-19 Fri	60	—	unknown	00:10–04:05 (good, 3.92 h)	89.6° 06:15	5.19	55%	35.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-06-20&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.