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: 07-17 (100), 07-16 (99), 07-15 (98), 07-14 (96), 07-13 (92) — by astronomy; check the weather when the night is within four days.

2037-06-18astronomy score per night — click a bar for that night2037-07-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-06-18 Thu	41	—	unknown	02:10–03:40 (good, 1.5 h)	89.8° 08:15	4.43	32%	119.2°
2037-06-19 Fri	43	—	unknown	02:05–03:40 (good, 1.58 h)	89.7° 08:10	4.42	43%	128.5°
2037-06-20 Sat	44	—	unknown	02:05–03:40 (good, 1.58 h)	89.6° 08:05	4.42	54%	136.0°
2037-06-21 Sun	45	—	unknown	02:05–03:40 (good, 1.58 h)	89.6° 08:05	4.42	65%	140.6°
2037-06-22 Mon	46	—	unknown	02:00–03:40 (good, 1.67 h)	89.7° 08:00	4.43	76%	141.2°
2037-06-23 Tue	46	—	unknown	02:00–03:40 (good, 1.67 h)	89.8° 07:55	4.43	85%	137.7°
2037-06-24 Wed	43	—	unknown	02:00–03:40 (good, 1.67 h)	89.7° 07:50	4.44	92%	131.2°
2037-06-25 Thu	43	—	unknown	01:55–03:40 (good, 1.75 h)	89.5° 07:45	4.45	97%	122.9°
2037-06-26 Fri	41	—	unknown	01:55–03:40 (good, 1.75 h)	89.6° 07:45	4.46	99%	113.5°
2037-06-27 Sat	37	—	unknown	02:00–03:40 (good, 1.67 h)	89.7° 07:40	4.47	100%	103.8°
2037-06-28 Sun	33	—	unknown	02:00–03:40 (good, 1.67 h)	89.8° 07:35	4.49	98%	93.9°
2037-06-29 Mon	30	—	unknown	02:35–03:40 (good, 1.08 h)	89.6° 07:30	4.51	95%	84.1°
2037-06-30 Tue	29	—	unknown	03:10–03:45 (good, 0.58 h)	89.5° 07:30	4.52	89%	74.6°
2037-07-01 Wed	29	—	unknown	03:25–03:45 (good, 0.33 h)	89.7° 07:25	4.55	83%	65.6°
2037-07-02 Thu	30	—	unknown	03:15–03:45 (good, 0.5 h)	89.8° 07:20	4.57	75%	57.2°
2037-07-03 Fri	33	—	unknown	02:05–03:45 (good, 1.67 h)	89.7° 07:15	4.59	66%	49.8°
2037-07-04 Sat	38	—	unknown	01:35–03:45 (good, 2.17 h)	89.6° 07:10	4.62	57%	43.8°
2037-07-05 Sun	50	—	unknown	01:05–03:50 (good, 2.75 h)	89.5° 07:10	4.65	47%	39.8°
2037-07-06 Mon	59	—	unknown	01:00–03:50 (good, 2.83 h)	89.7° 07:05	4.68	38%	38.6°
2037-07-07 Tue	66	—	unknown	00:55–03:50 (good, 2.92 h)	89.8° 07:00	4.71	28%	40.7°
2037-07-08 Wed	73	—	unknown	00:50–03:50 (good, 3.0 h)	89.7° 06:55	4.74	20%	45.6°
2037-07-09 Thu	80	—	unknown	00:50–03:50 (good, 3.0 h)	89.5° 06:50	4.78	12%	52.9°
2037-07-10 Fri	86	—	unknown	00:45–03:55 (good, 3.17 h)	89.6° 06:50	4.81	6%	61.9°
2037-07-11 Sat	89	—	unknown	00:40–03:55 (good, 3.25 h)	89.7° 06:45	4.85	2%	72.0°
2037-07-12 Sun	90	—	unknown	00:35–03:55 (good, 3.33 h)	89.8° 06:40	4.89	0%	82.8°
2037-07-13 Mon	92	—	unknown	00:35–03:55 (good, 3.33 h)	89.7° 06:35	4.93	1%	94.1°
2037-07-14 Tue	96	—	unknown	00:30–04:00 (good, 3.5 h)	89.5° 06:30	4.97	5%	105.4°
2037-07-15 Wed	98	—	unknown	00:25–04:00 (good, 3.58 h)	89.7° 06:30	5.01	11%	116.3°
2037-07-16 Thu	99	—	unknown	00:20–04:00 (good, 3.67 h)	89.8° 06:25	5.06	19%	126.2°
2037-07-17 Fri	100	—	unknown	00:15–04:05 (good, 3.83 h)	89.7° 06:20	5.1	29%	134.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-06-18&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.