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 Seven Sisters: 01-27 (100), 01-28 (100), 01-29 (100), 01-30 (100), 01-31 (100) — by astronomy; check the weather when the night is within four days.

2043-01-25astronomy score per night — click a bar for that night2043-02-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-01-25 Sun	64	—	unknown	19:05–21:35 (good, 2.5 h)	72.6° 19:50	10.98	99%	73.9°
2043-01-26 Mon	80	—	unknown	19:05–23:15 (good, 4.17 h)	72.5° 19:45	10.95	97%	87.1°
2043-01-27 Tue	100	—	unknown	19:10–00:30 (good, 5.33 h)	72.5° 19:40	10.92	92%	100.0°
2043-01-28 Wed	100	—	unknown	19:10–00:35 (good, 5.42 h)	72.5° 19:40	10.89	86%	112.5°
2043-01-29 Thu	100	—	unknown	19:10–00:35 (good, 5.42 h)	72.6° 19:35	10.86	79%	124.8°
2043-01-30 Fri	100	—	unknown	19:10–00:35 (good, 5.42 h)	72.6° 19:30	10.83	70%	136.9°
2043-01-31 Sat	100	—	unknown	19:15–00:35 (good, 5.33 h)	72.5° 19:25	10.79	62%	148.8°
2043-02-01 Sun	100	—	unknown	19:15–00:35 (good, 5.33 h)	72.5° 19:25	10.76	52%	160.6°
2043-02-02 Mon	100	—	unknown	19:15–00:30 (good, 5.25 h)	72.6° 19:20	10.73	43%	172.5°
2043-02-03 Tue	100	—	unknown	19:15–00:25 (good, 5.17 h)	72.6° 19:15	10.69	34%	175.6°
2043-02-04 Wed	100	—	unknown	19:15–00:20 (good, 5.08 h)	72.6° 19:10	10.66	25%	163.4°
2043-02-05 Thu	100	—	unknown	19:20–00:20 (good, 5.0 h)	72.5° 19:05	10.63	17%	151.0°
2043-02-06 Fri	100	—	unknown	19:20–00:15 (good, 4.92 h)	72.5° 19:05	10.59	10%	138.3°
2043-02-07 Sat	100	—	unknown	19:20–00:10 (good, 4.83 h)	72.6° 19:00	10.55	5%	125.3°
2043-02-08 Sun	100	—	unknown	19:20–00:05 (good, 4.75 h)	72.6° 18:55	10.52	1%	111.9°
2043-02-09 Mon	100	—	unknown	19:25–00:00 (good, 4.58 h)	72.5° 18:50	10.48	0%	98.1°
2043-02-10 Tue	100	—	unknown	19:25–00:00 (good, 4.58 h)	72.5° 18:45	10.44	2%	84.1°
2043-02-11 Wed	100	—	unknown	19:25–23:55 (good, 4.5 h)	72.5° 18:45	10.41	5%	69.9°
2043-02-12 Thu	98	—	unknown	19:25–23:50 (good, 4.42 h)	72.6° 18:40	10.37	12%	55.6°
2043-02-13 Fri	91	—	unknown	19:30–23:45 (good, 4.25 h)	72.6° 18:35	10.33	20%	41.2°
2043-02-14 Sat	76	—	unknown	19:30–23:45 (good, 4.25 h)	72.5° 18:30	10.29	30%	26.9°
2043-02-15 Sun	57	—	unknown	19:30–23:15 (good, 3.75 h)	72.5° 18:30	10.25	41%	12.7°
2043-02-16 Mon	41	—	unknown	19:40–20:55 (good, 1.25 h)	72.6° 18:25	10.21	53%	1.4°
2043-02-17 Tue	28	—	unknown	19:30–23:45 (marginal, 4.25 h)	72.6° 18:20	10.17	64%	15.4°
2043-02-18 Wed	18	—	unknown	19:35–23:25 (marginal, 3.83 h)	72.6° 18:15	10.13	74%	29.2°
2043-02-19 Thu	19	—	unknown	19:35–23:15 (marginal, 3.67 h)	72.5° 18:10	10.09	83%	42.8°
2043-02-20 Fri	23	—	unknown	19:35–23:15 (marginal, 3.67 h)	72.5° 18:10	10.05	90%	56.3°
2043-02-21 Sat	30	—	unknown	19:35–23:20 (marginal, 3.75 h)	72.6° 18:05	10.0	96%	69.6°
2043-02-22 Sun	40	—	unknown	19:40–20:55 (good, 1.25 h)	72.6° 18:00	9.96	99%	82.6°
2043-02-23 Mon	52	—	unknown	19:40–22:05 (good, 2.42 h)	72.5° 17:55	9.92	100%	95.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-01-25&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.