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: 01-25 (99), 01-23 (98), 01-24 (98), 01-26 (97), 01-27 (95) — by astronomy; check the weather when the night is within four days.

2038-01-20astronomy score per night — click a bar for that night2038-02-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-01-20 Wed	56	—	unknown	19:00–21:20 (good, 2.33 h)	89.8° 17:05	11.11	100%	89.7°
2038-01-21 Thu	70	—	unknown	19:00–22:30 (good, 3.5 h)	89.6° 17:00	11.08	99%	100.7°
2038-01-22 Fri	82	—	unknown	19:05–22:45 (good, 3.67 h)	89.5° 17:00	11.05	96%	111.6°
2038-01-23 Sat	98	—	unknown	19:05–22:50 (good, 3.75 h)	89.7° 16:55	11.03	90%	122.0°
2038-01-24 Sun	98	—	unknown	19:05–22:50 (good, 3.75 h)	89.8° 16:50	11.0	82%	131.0°
2038-01-25 Mon	99	—	unknown	19:05–22:50 (good, 3.75 h)	89.7° 16:45	10.97	72%	137.9°
2038-01-26 Tue	97	—	unknown	19:10–22:50 (good, 3.67 h)	89.6° 16:40	10.94	61%	141.3°
2038-01-27 Wed	95	—	unknown	19:10–22:45 (good, 3.58 h)	89.6° 16:40	10.91	50%	140.4°
2038-01-28 Thu	93	—	unknown	19:10–22:45 (good, 3.58 h)	89.7° 16:35	10.88	39%	135.7°
2038-01-29 Fri	91	—	unknown	19:10–22:40 (good, 3.5 h)	89.8° 16:30	10.85	28%	128.3°
2038-01-30 Sat	89	—	unknown	19:10–22:35 (good, 3.42 h)	89.7° 16:25	10.82	19%	119.4°
2038-01-31 Sun	86	—	unknown	19:15–22:30 (good, 3.25 h)	89.5° 16:20	10.79	11%	109.7°
2038-02-01 Mon	83	—	unknown	19:15–22:25 (good, 3.17 h)	89.6° 16:20	10.75	6%	99.7°
2038-02-02 Tue	80	—	unknown	19:15–22:25 (good, 3.17 h)	89.8° 16:15	10.72	2%	89.6°
2038-02-03 Wed	78	—	unknown	19:15–22:20 (good, 3.08 h)	89.8° 16:10	10.69	0%	79.6°
2038-02-04 Thu	75	—	unknown	19:20–22:15 (good, 2.92 h)	89.6° 16:05	10.65	0%	70.0°
2038-02-05 Fri	73	—	unknown	19:20–22:10 (good, 2.83 h)	89.5° 16:05	10.62	3%	61.1°
2038-02-06 Sat	69	—	unknown	19:20–22:05 (good, 2.75 h)	89.7° 16:00	10.58	7%	53.0°
2038-02-07 Sun	63	—	unknown	19:20–22:05 (good, 2.75 h)	89.8° 15:55	10.55	13%	46.1°
2038-02-08 Mon	56	—	unknown	19:20–22:00 (good, 2.67 h)	89.7° 15:50	10.51	20%	41.1°
2038-02-09 Tue	46	—	unknown	19:25–21:40 (good, 2.25 h)	89.6° 15:45	10.47	28%	38.7°
2038-02-10 Wed	38	—	unknown	19:25–21:30 (good, 2.08 h)	89.6° 15:45	10.44	36%	39.1°
2038-02-11 Thu	30	—	unknown	19:25–21:00 (good, 1.58 h)	89.7° 15:40	10.4	46%	42.5°
2038-02-12 Fri	25	—	unknown	18:55–22:10 (marginal, 3.25 h)	89.8° 15:35	10.36	55%	48.3°
2038-02-13 Sat	21	—	unknown	19:30–22:00 (marginal, 2.5 h)	89.7° 15:30	10.32	65%	55.8°
2038-02-14 Sun	19	—	unknown	19:30–21:55 (marginal, 2.42 h)	89.5° 15:25	10.28	74%	64.7°
2038-02-15 Mon	19	—	unknown	19:30–21:50 (marginal, 2.33 h)	89.6° 15:25	10.24	83%	74.5°
2038-02-16 Tue	21	—	unknown	19:00–21:50 (marginal, 2.83 h)	89.7° 15:20	10.2	90%	85.0°
2038-02-17 Wed	25	—	unknown	19:30–20:20 (good, 0.83 h)	89.8° 15:15	10.16	96%	96.0°
2038-02-18 Thu	29	—	unknown	19:35–20:55 (good, 1.33 h)	89.7° 15:10	10.12	99%	107.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-01-20&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.