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: 07-15 (99), 07-14 (97), 07-13 (94), 07-12 (91), 07-11 (89) — by astronomy; check the weather when the night is within four days.

2040-06-16astronomy score per night — click a bar for that night2040-07-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-06-16 Sat	39	—	unknown	02:20–03:40 (good, 1.33 h)	89.6° 08:20	4.44	40%	124.3°
2040-06-17 Sun	40	—	unknown	02:15–03:40 (good, 1.42 h)	89.5° 08:20	4.43	50%	132.4°
2040-06-18 Mon	42	—	unknown	02:10–03:40 (good, 1.5 h)	89.7° 08:15	4.43	61%	139.0°
2040-06-19 Tue	42	—	unknown	02:10–03:40 (good, 1.5 h)	89.8° 08:10	4.42	71%	143.1°
2040-06-20 Wed	43	—	unknown	02:10–03:40 (good, 1.5 h)	89.7° 08:05	4.42	80%	143.2°
2040-06-21 Thu	44	—	unknown	02:05–03:40 (good, 1.58 h)	89.6° 08:00	4.42	88%	139.0°
2040-06-22 Fri	40	—	unknown	02:05–03:40 (good, 1.58 h)	89.6° 08:00	4.43	95%	131.3°
2040-06-23 Sat	41	—	unknown	02:00–03:40 (good, 1.67 h)	89.7° 07:55	4.43	99%	121.3°
2040-06-24 Sun	37	—	unknown	02:05–03:40 (good, 1.58 h)	89.8° 07:50	4.44	100%	109.9°
2040-06-25 Mon	33	—	unknown	02:10–03:40 (good, 1.5 h)	89.7° 07:45	4.45	98%	97.8°
2040-06-26 Tue	30	—	unknown	02:15–03:40 (good, 1.42 h)	89.5° 07:40	4.46	93%	85.6°
2040-06-27 Wed	28	—	unknown	02:50–03:40 (good, 0.83 h)	89.6° 07:40	4.48	86%	73.8°
2040-06-28 Thu	28	—	unknown	02:55–03:40 (good, 0.75 h)	89.8° 07:35	4.49	76%	62.6°
2040-06-29 Fri	31	—	unknown	02:05–03:45 (good, 1.67 h)	89.8° 07:30	4.51	66%	52.6°
2040-06-30 Sat	35	—	unknown	01:50–03:45 (good, 1.92 h)	89.6° 07:25	4.53	55%	44.3°
2040-07-01 Sun	44	—	unknown	01:20–03:45 (good, 2.42 h)	89.5° 07:25	4.55	45%	38.6°
2040-07-02 Mon	52	—	unknown	01:15–03:45 (good, 2.5 h)	89.7° 07:20	4.57	34%	36.3°
2040-07-03 Tue	59	—	unknown	01:10–03:45 (good, 2.58 h)	89.8° 07:15	4.6	25%	37.8°
2040-07-04 Wed	65	—	unknown	01:05–03:45 (good, 2.67 h)	89.7° 07:10	4.63	17%	42.4°
2040-07-05 Thu	72	—	unknown	01:05–03:50 (good, 2.75 h)	89.6° 07:05	4.66	10%	49.2°
2040-07-06 Fri	77	—	unknown	01:00–03:50 (good, 2.83 h)	89.6° 07:05	4.69	5%	57.3°
2040-07-07 Sat	79	—	unknown	00:55–03:50 (good, 2.92 h)	89.7° 07:00	4.72	2%	66.1°
2040-07-08 Sun	80	—	unknown	00:50–03:50 (good, 3.0 h)	89.8° 06:55	4.75	0%	75.4°
2040-07-09 Mon	85	—	unknown	00:45–03:55 (good, 3.17 h)	89.7° 06:50	4.79	0%	84.8°
2040-07-10 Tue	87	—	unknown	00:45–03:55 (good, 3.17 h)	89.5° 06:45	4.82	2%	94.3°
2040-07-11 Wed	89	—	unknown	00:40–03:55 (good, 3.25 h)	89.6° 06:45	4.86	6%	103.8°
2040-07-12 Thu	91	—	unknown	00:35–03:55 (good, 3.33 h)	89.8° 06:40	4.9	11%	113.2°
2040-07-13 Fri	94	—	unknown	00:30–04:00 (good, 3.5 h)	89.8° 06:35	4.94	18%	122.2°
2040-07-14 Sat	97	—	unknown	00:30–04:00 (good, 3.5 h)	89.6° 06:30	4.98	26%	130.4°
2040-07-15 Sun	99	—	unknown	00:25–04:00 (good, 3.58 h)	89.5° 06:30	5.02	35%	137.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-06-16&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.