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: 02-24 (32), 02-25 (32), 02-26 (31), 02-22 (30), 02-23 (30) — by astronomy; check the weather when the night is within four days.

2035-02-16astronomy score per night — click a bar for that night2035-03-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-02-16 Fri	20	—	unknown	19:30–21:55 (marginal, 2.42 h)	89.8° 15:20	10.21	66%	60.0°
2035-02-17 Sat	19	—	unknown	19:30–21:45 (marginal, 2.25 h)	89.7° 15:15	10.17	76%	70.7°
2035-02-18 Sun	19	—	unknown	19:35–21:45 (marginal, 2.17 h)	89.5° 15:10	10.13	85%	81.9°
2035-02-19 Mon	22	—	unknown	19:35–20:05 (good, 0.5 h)	89.6° 15:10	10.09	92%	93.4°
2035-02-20 Tue	25	—	unknown	19:35–20:45 (good, 1.17 h)	89.7° 15:05	10.05	97%	104.6°
2035-02-21 Wed	29	—	unknown	19:35–20:50 (good, 1.25 h)	89.7° 15:00	10.01	100%	115.4°
2035-02-22 Thu	30	—	unknown	19:40–20:55 (good, 1.25 h)	89.6° 14:55	9.96	100%	125.3°
2035-02-23 Fri	30	—	unknown	19:40–20:50 (good, 1.17 h)	89.5° 14:55	9.92	97%	133.7°
2035-02-24 Sat	32	—	unknown	19:40–20:50 (good, 1.17 h)	89.7° 14:50	9.88	92%	139.8°
2035-02-25 Sun	32	—	unknown	19:40–20:55 (good, 1.25 h)	89.8° 14:45	9.83	86%	142.9°
2035-02-26 Mon	31	—	unknown	19:40–20:50 (good, 1.17 h)	89.7° 14:40	9.79	79%	142.4°
2035-02-27 Tue	28	—	unknown	19:45–20:45 (good, 1.0 h)	89.6° 14:35	9.75	70%	138.6°
2035-02-28 Wed	27	—	unknown	19:45–20:40 (good, 0.92 h)	89.6° 14:35	9.7	61%	132.6°
2035-03-01 Thu	25	—	unknown	19:45–20:40 (good, 0.92 h)	89.7° 14:30	9.66	52%	125.1°
2035-03-02 Fri	23	—	unknown	19:45–20:35 (good, 0.83 h)	89.8° 14:25	9.61	42%	116.6°
2035-03-03 Sat	22	—	unknown	19:50–20:30 (good, 0.67 h)	89.7° 14:20	9.56	33%	107.6°
2035-03-04 Sun	20	—	unknown	19:50–20:25 (good, 0.58 h)	89.5° 14:15	9.52	24%	98.2°
2035-03-05 Mon	18	—	unknown	19:50–20:20 (good, 0.5 h)	89.6° 14:15	9.47	17%	88.4°
2035-03-06 Tue	17	—	unknown	19:50–20:20 (good, 0.5 h)	89.7° 14:10	9.42	10%	78.5°
2035-03-07 Wed	14	—	unknown	19:55–20:15 (good, 0.33 h)	89.7° 14:05	9.38	5%	68.5°
2035-03-08 Thu	13	—	unknown	19:55–20:10 (good, 0.25 h)	89.6° 14:00	9.33	1%	58.8°
2035-03-09 Fri	11	—	unknown	19:55–20:05 (good, 0.17 h)	89.5° 14:00	9.28	0%	49.8°
2035-03-10 Sat	10	—	unknown	19:55–20:05 (good, 0.17 h)	89.7° 13:55	9.23	1%	42.4°
2035-03-11 Sun	7	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.8° 13:50	9.18	5%	37.7°
2035-03-12 Mon	6	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.7° 13:45	9.13	11%	37.2°
2035-03-13 Tue	5	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.6° 13:40	9.09	19%	41.1°
2035-03-14 Wed	3	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.6° 13:40	9.04	29%	48.4°
2035-03-15 Thu	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.7° 13:35	8.99	40%	57.7°
2035-03-16 Fri	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.8° 13:30	8.94	51%	68.1°
2035-03-17 Sat	1	—	unknown	—	89.7° 13:25	8.88	62%	79.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-02-16&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.