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: 08-24 (100), 08-25 (100), 08-26 (100), 08-27 (100), 08-28 (100) — by astronomy; check the weather when the night is within four days.

2038-08-19astronomy score per night — click a bar for that night2038-09-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-08-19 Thu	81	—	unknown	22:10–22:50 (good, 0.67 h)	89.6° 04:10	6.88	77%	38.5°
2038-08-20 Fri	84	—	unknown	22:05–02:30 (good, 4.42 h)	89.6° 04:10	6.94	69%	38.7°
2038-08-21 Sat	88	—	unknown	22:00–04:55 (good, 6.92 h)	89.7° 04:05	6.99	60%	41.8°
2038-08-22 Sun	91	—	unknown	21:55–05:00 (good, 7.08 h)	89.8° 04:00	7.05	50%	47.3°
2038-08-23 Mon	96	—	unknown	21:55–05:00 (good, 7.08 h)	89.7° 03:55	7.11	41%	54.5°
2038-08-24 Tue	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.5° 03:50	7.16	31%	63.0°
2038-08-25 Wed	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.6° 03:50	7.22	22%	72.3°
2038-08-26 Thu	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.8° 03:45	7.28	14%	82.2°
2038-08-27 Fri	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.8° 03:40	7.33	8%	92.7°
2038-08-28 Sat	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.6° 03:35	7.39	3%	103.4°
2038-08-29 Sun	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.5° 03:35	7.45	0%	114.0°
2038-08-30 Mon	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.7° 03:30	7.5	0%	124.1°
2038-08-31 Tue	100	—	unknown	21:35–05:10 (good, 7.58 h)	89.8° 03:25	7.56	3%	133.0°
2038-09-01 Wed	100	—	unknown	21:35–05:10 (good, 7.58 h)	89.7° 03:20	7.62	9%	139.4°
2038-09-02 Thu	100	—	unknown	21:35–05:15 (good, 7.67 h)	89.6° 03:15	7.67	17%	141.9°
2038-09-03 Fri	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.6° 03:15	7.73	26%	139.8°
2038-09-04 Sat	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.7° 03:10	7.78	37%	133.9°
2038-09-05 Sun	100	—	unknown	21:25–05:15 (good, 7.83 h)	89.8° 03:05	7.84	48%	125.6°
2038-09-06 Mon	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.7° 03:00	7.89	60%	115.9°
2038-09-07 Tue	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.5° 02:55	7.95	70%	105.8°
2038-09-08 Wed	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.6° 02:55	8.0	79%	95.4°
2038-09-09 Thu	100	—	unknown	21:20–05:25 (good, 8.08 h)	89.8° 02:50	8.06	87%	85.0°
2038-09-10 Fri	100	—	unknown	22:35–05:25 (good, 6.83 h)	89.8° 02:45	8.11	93%	75.0°
2038-09-11 Sat	73	—	unknown	01:35–05:25 (good, 3.83 h)	89.6° 02:40	8.16	97%	65.4°
2038-09-12 Sun	63	—	unknown	04:40–05:25 (good, 0.75 h)	89.5° 02:40	8.22	100%	56.5°
2038-09-13 Mon	54	—	unknown	21:10–05:30 (marginal, 8.33 h)	89.7° 02:35	8.27	100%	48.8°
2038-09-14 Tue	49	—	unknown	21:10–05:30 (marginal, 8.33 h)	89.8° 02:30	8.32	98%	42.7°
2038-09-15 Wed	52	—	unknown	21:10–05:30 (marginal, 8.33 h)	89.7° 02:25	8.38	94%	38.9°
2038-09-16 Thu	83	—	unknown	21:05–21:20 (good, 0.25 h)	89.6° 02:20	8.43	89%	38.1°
2038-09-17 Fri	86	—	unknown	21:05–22:45 (good, 1.67 h)	89.6° 02:20	8.48	83%	40.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-08-19&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.