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: 01-12 (100), 01-13 (100), 01-14 (100), 01-15 (100), 01-16 (100) — by astronomy; check the weather when the night is within four days.

2038-12-31astronomy score per night — click a bar for that night2039-01-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-12-31 Fri	87	—	unknown	18:45–00:35 (good, 5.83 h)	89.8° 18:25	11.46	37%	49.7°
2039-01-01 Sat	77	—	unknown	18:45–00:30 (good, 5.75 h)	89.7° 18:20	11.45	46%	43.3°
2039-01-02 Sun	66	—	unknown	18:45–23:55 (good, 5.17 h)	89.5° 18:15	11.44	56%	39.2°
2039-01-03 Mon	50	—	unknown	18:45–00:50 (marginal, 6.08 h)	89.6° 18:15	11.43	65%	38.0°
2039-01-04 Tue	39	—	unknown	18:45–00:35 (marginal, 5.83 h)	89.8° 18:10	11.42	74%	39.9°
2039-01-05 Wed	33	—	unknown	18:45–00:20 (marginal, 5.58 h)	89.8° 18:05	11.4	82%	44.5°
2039-01-06 Thu	32	—	unknown	18:50–00:10 (marginal, 5.33 h)	89.6° 18:00	11.39	88%	51.0°
2039-01-07 Fri	35	—	unknown	18:50–00:00 (marginal, 5.17 h)	89.5° 18:00	11.38	94%	58.9°
2039-01-08 Sat	43	—	unknown	18:50–00:00 (marginal, 5.17 h)	89.7° 17:55	11.36	98%	67.7°
2039-01-09 Sun	53	—	unknown	18:50–20:40 (good, 1.83 h)	89.8° 17:50	11.34	100%	77.1°
2039-01-10 Mon	67	—	unknown	18:50–21:45 (good, 2.92 h)	89.7° 17:45	11.33	100%	87.0°
2039-01-11 Tue	82	—	unknown	18:50–22:55 (good, 4.08 h)	89.6° 17:40	11.31	98%	97.1°
2039-01-12 Wed	100	—	unknown	18:55–23:25 (good, 4.5 h)	89.6° 17:40	11.29	94%	107.2°
2039-01-13 Thu	100	—	unknown	18:55–23:30 (good, 4.58 h)	89.7° 17:35	11.27	88%	117.1°
2039-01-14 Fri	100	—	unknown	18:55–23:30 (good, 4.58 h)	89.8° 17:30	11.25	80%	126.3°
2039-01-15 Sat	100	—	unknown	18:55–23:30 (good, 4.58 h)	89.7° 17:25	11.23	70%	134.2°
2039-01-16 Sun	100	—	unknown	18:55–23:30 (good, 4.58 h)	89.5° 17:20	11.21	59%	139.9°
2039-01-17 Mon	100	—	unknown	19:00–23:25 (good, 4.42 h)	89.6° 17:20	11.18	48%	142.0°
2039-01-18 Tue	100	—	unknown	19:00–23:25 (good, 4.42 h)	89.8° 17:15	11.16	37%	139.8°
2039-01-19 Wed	100	—	unknown	19:00–23:20 (good, 4.33 h)	89.8° 17:10	11.14	26%	133.9°
2039-01-20 Thu	100	—	unknown	19:00–23:15 (good, 4.25 h)	89.7° 17:05	11.11	17%	125.3°
2039-01-21 Fri	100	—	unknown	19:00–23:10 (good, 4.17 h)	89.5° 17:05	11.09	9%	115.2°
2039-01-22 Sat	100	—	unknown	19:05–23:05 (good, 4.0 h)	89.7° 17:00	11.06	4%	104.3°
2039-01-23 Sun	100	—	unknown	19:05–23:05 (good, 4.0 h)	89.8° 16:55	11.03	1%	93.1°
2039-01-24 Mon	100	—	unknown	19:05–23:00 (good, 3.92 h)	89.7° 16:50	11.01	0%	82.0°
2039-01-25 Tue	100	—	unknown	19:05–22:55 (good, 3.83 h)	89.6° 16:45	10.98	2%	71.4°
2039-01-26 Wed	97	—	unknown	19:05–22:50 (good, 3.75 h)	89.6° 16:45	10.95	7%	61.5°
2039-01-27 Thu	89	—	unknown	19:10–22:50 (good, 3.67 h)	89.7° 16:40	10.92	13%	52.6°
2039-01-28 Fri	79	—	unknown	19:10–22:45 (good, 3.58 h)	89.8° 16:35	10.89	20%	45.3°
2039-01-29 Sat	66	—	unknown	19:10–22:30 (good, 3.33 h)	89.7° 16:30	10.86	29%	40.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-12-31&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.