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: 07-19 (100), 07-20 (100), 07-21 (100), 07-22 (100), 07-23 (100) — by astronomy; check the weather when the night is within four days.

2028-07-12astronomy score per night — click a bar for that night2028-08-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-07-12 Wed	33	—	unknown	00:05–03:55 (marginal, 3.83 h)	89.7° 06:40	4.9	68%	38.7°
2028-07-13 Thu	38	—	unknown	03:05–04:00 (good, 0.92 h)	89.7° 06:35	4.94	59%	32.0°
2028-07-14 Fri	49	—	unknown	00:55–04:00 (good, 3.08 h)	89.6° 06:30	4.98	49%	28.3°
2028-07-15 Sat	61	—	unknown	00:25–04:00 (good, 3.58 h)	89.5° 06:25	5.02	40%	29.2°
2028-07-16 Sun	75	—	unknown	00:20–04:00 (good, 3.67 h)	89.6° 06:25	5.06	30%	34.4°
2028-07-17 Mon	88	—	unknown	00:15–04:05 (good, 3.83 h)	89.7° 06:20	5.11	21%	42.8°
2028-07-18 Tue	95	—	unknown	00:10–04:05 (good, 3.92 h)	89.7° 06:15	5.15	13%	53.0°
2028-07-19 Wed	100	—	unknown	00:10–04:05 (good, 3.92 h)	89.6° 06:10	5.2	6%	64.5°
2028-07-20 Thu	100	—	unknown	00:05–04:10 (good, 4.08 h)	89.5° 06:10	5.25	2%	76.8°
2028-07-21 Fri	100	—	unknown	00:00–04:10 (good, 4.17 h)	89.6° 06:05	5.3	0%	89.5°
2028-07-22 Sat	100	—	unknown	23:55–04:10 (good, 4.25 h)	89.7° 06:00	5.35	1%	102.5°
2028-07-23 Sun	100	—	unknown	23:50–04:10 (good, 4.33 h)	89.7° 05:55	5.4	5%	115.4°
2028-07-24 Mon	100	—	unknown	23:50–04:15 (good, 4.42 h)	89.5° 05:50	5.45	11%	127.8°
2028-07-25 Tue	100	—	unknown	23:45–04:15 (good, 4.5 h)	89.5° 05:50	5.5	20%	138.9°
2028-07-26 Wed	100	—	unknown	23:40–04:15 (good, 4.58 h)	89.7° 05:45	5.55	30%	147.6°
2028-07-27 Thu	100	—	unknown	23:35–04:20 (good, 4.75 h)	89.7° 05:40	5.6	41%	151.8°
2028-07-28 Fri	100	—	unknown	23:35–04:20 (good, 4.75 h)	89.6° 05:35	5.66	52%	149.9°
2028-07-29 Sat	100	—	unknown	23:35–04:20 (good, 4.75 h)	89.5° 05:30	5.71	63%	143.2°
2028-07-30 Sun	100	—	unknown	23:30–04:25 (good, 4.92 h)	89.6° 05:30	5.77	73%	134.0°
2028-07-31 Mon	100	—	unknown	23:30–04:25 (good, 4.92 h)	89.7° 05:25	5.82	82%	123.7°
2028-08-01 Tue	100	—	unknown	23:30–04:25 (good, 4.92 h)	89.7° 05:20	5.88	89%	112.9°
2028-08-02 Wed	100	—	unknown	23:35–04:30 (good, 4.92 h)	89.6° 05:15	5.93	94%	102.0°
2028-08-03 Thu	80	—	unknown	23:50–04:30 (good, 4.67 h)	89.5° 05:15	5.99	98%	91.1°
2028-08-04 Fri	70	—	unknown	01:05–04:30 (good, 3.42 h)	89.6° 05:10	6.04	100%	80.3°
2028-08-05 Sat	56	—	unknown	02:55–04:35 (good, 1.67 h)	89.7° 05:05	6.1	100%	69.8°
2028-08-06 Sun	45	—	unknown	22:35–04:35 (marginal, 6.0 h)	89.7° 05:00	6.16	98%	59.6°
2028-08-07 Mon	36	—	unknown	22:35–04:35 (marginal, 6.0 h)	89.5° 04:55	6.21	94%	49.9°
2028-08-08 Tue	34	—	unknown	22:30–04:35 (marginal, 6.08 h)	89.5° 04:55	6.27	88%	41.1°
2028-08-09 Wed	37	—	unknown	22:20–04:40 (marginal, 6.33 h)	89.7° 04:50	6.33	82%	33.7°
2028-08-10 Thu	44	—	unknown	22:15–04:40 (marginal, 6.42 h)	89.7° 04:45	6.38	74%	29.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-07-12&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.