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: 06-23 (50), 06-22 (48), 06-21 (46), 06-20 (44), 06-19 (42) — by astronomy; check the weather when the night is within four days.

2028-05-25astronomy score per night — click a bar for that night2028-06-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-05-25 Thu	12	—	unknown	03:45–03:50 (good, 0.08 h)	89.5° 09:50	5.06	3%	61.6°
2028-05-26 Fri	13	—	unknown	03:40–03:50 (good, 0.17 h)	89.7° 09:45	5.01	8%	73.4°
2028-05-27 Sat	14	—	unknown	03:35–03:50 (good, 0.25 h)	89.7° 09:40	4.97	15%	85.6°
2028-05-28 Sun	15	—	unknown	03:30–03:50 (good, 0.33 h)	89.7° 09:35	4.93	24%	98.0°
2028-05-29 Mon	16	—	unknown	03:30–03:50 (good, 0.33 h)	89.5° 09:30	4.89	34%	110.3°
2028-05-30 Tue	17	—	unknown	03:25–03:45 (good, 0.33 h)	89.6° 09:30	4.85	46%	122.3°
2028-05-31 Wed	18	—	unknown	03:20–03:45 (good, 0.42 h)	89.7° 09:25	4.81	57%	133.6°
2028-06-01 Thu	19	—	unknown	03:15–03:45 (good, 0.5 h)	89.7° 09:20	4.78	68%	143.4°
2028-06-02 Fri	21	—	unknown	03:15–03:45 (good, 0.5 h)	89.6° 09:15	4.74	78%	150.1°
2028-06-03 Sat	22	—	unknown	03:15–03:45 (good, 0.5 h)	89.5° 09:10	4.71	87%	151.5°
2028-06-04 Sun	20	—	unknown	03:15–03:40 (good, 0.42 h)	89.6° 09:10	4.68	93%	147.1°
2028-06-05 Mon	20	—	unknown	03:10–03:40 (good, 0.5 h)	89.7° 09:05	4.65	98%	138.7°
2028-06-06 Tue	20	—	unknown	03:10–03:40 (good, 0.5 h)	89.7° 09:00	4.62	100%	128.6°
2028-06-07 Wed	21	—	unknown	03:05–03:40 (good, 0.58 h)	89.6° 08:55	4.59	99%	117.7°
2028-06-08 Thu	19	—	unknown	03:10–03:40 (good, 0.5 h)	89.5° 08:55	4.57	97%	106.6°
2028-06-09 Fri	18	—	unknown	03:10–03:40 (good, 0.5 h)	89.7° 08:50	4.54	92%	95.5°
2028-06-10 Sat	17	—	unknown	03:20–03:40 (good, 0.33 h)	89.7° 08:45	4.52	86%	84.6°
2028-06-11 Sun	16	—	unknown	02:05–03:40 (marginal, 1.58 h)	89.7° 08:40	4.5	79%	73.9°
2028-06-12 Mon	17	—	unknown	02:00–03:40 (marginal, 1.67 h)	89.5° 08:35	4.49	71%	63.6°
2028-06-13 Tue	18	—	unknown	01:55–04:30 (marginal, 2.58 h)	89.6° 08:35	4.47	62%	53.7°
2028-06-14 Wed	20	—	unknown	02:55–03:40 (good, 0.75 h)	89.7° 08:30	4.46	52%	44.4°
2028-06-15 Thu	23	—	unknown	02:45–03:40 (good, 0.92 h)	89.7° 08:25	4.45	43%	36.4°
2028-06-16 Fri	27	—	unknown	02:35–03:40 (good, 1.08 h)	89.6° 08:20	4.44	34%	30.4°
2028-06-17 Sat	32	—	unknown	02:25–03:40 (good, 1.25 h)	89.5° 08:15	4.43	25%	28.1°
2028-06-18 Sun	37	—	unknown	02:10–03:40 (good, 1.5 h)	89.6° 08:15	4.43	16%	30.7°
2028-06-19 Mon	42	—	unknown	02:05–03:40 (good, 1.58 h)	89.7° 08:10	4.42	10%	37.4°
2028-06-20 Tue	44	—	unknown	02:00–03:40 (good, 1.67 h)	89.7° 08:05	4.42	4%	46.7°
2028-06-21 Wed	46	—	unknown	02:00–03:40 (good, 1.67 h)	89.6° 08:00	4.42	1%	57.5°
2028-06-22 Thu	48	—	unknown	01:55–03:40 (good, 1.75 h)	89.5° 08:00	4.43	0%	69.4°
2028-06-23 Fri	50	—	unknown	01:50–03:40 (good, 1.83 h)	89.7° 07:55	4.43	2%	81.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-05-25&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.