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: 01-20 (100), 01-21 (100), 01-22 (100), 01-23 (100), 01-24 (100) — by astronomy; check the weather when the night is within four days.

2044-01-20astronomy score per night — click a bar for that night2044-02-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-01-20 Wed	100	—	unknown	19:00–01:15 (good, 6.25 h)	72.6° 20:10	11.12	60%	138.9°
2044-01-21 Thu	100	—	unknown	19:00–01:15 (good, 6.25 h)	72.5° 20:05	11.09	50%	151.2°
2044-01-22 Fri	100	—	unknown	19:05–01:15 (good, 6.17 h)	72.6° 20:05	11.07	41%	163.3°
2044-01-23 Sat	100	—	unknown	19:05–01:10 (good, 6.08 h)	72.6° 20:00	11.04	32%	175.2°
2044-01-24 Sun	100	—	unknown	19:05–01:05 (good, 6.0 h)	72.6° 19:55	11.01	24%	172.9°
2044-01-25 Mon	100	—	unknown	19:05–01:00 (good, 5.92 h)	72.6° 19:50	10.98	16%	161.2°
2044-01-26 Tue	100	—	unknown	19:05–01:00 (good, 5.92 h)	72.5° 19:45	10.95	10%	149.3°
2044-01-27 Wed	100	—	unknown	19:10–00:55 (good, 5.75 h)	72.6° 19:45	10.93	5%	137.3°
2044-01-28 Thu	100	—	unknown	19:10–00:50 (good, 5.67 h)	72.6° 19:40	10.9	2%	125.2°
2044-01-29 Fri	100	—	unknown	19:10–00:45 (good, 5.58 h)	72.6° 19:35	10.86	0%	112.9°
2044-01-30 Sat	100	—	unknown	19:10–00:45 (good, 5.58 h)	72.6° 19:30	10.83	1%	100.4°
2044-01-31 Sun	100	—	unknown	19:15–00:40 (good, 5.42 h)	72.5° 19:30	10.8	3%	87.7°
2044-02-01 Mon	100	—	unknown	19:15–00:35 (good, 5.33 h)	72.6° 19:25	10.77	8%	74.8°
2044-02-02 Tue	100	—	unknown	19:15–00:30 (good, 5.25 h)	72.6° 19:20	10.74	14%	61.7°
2044-02-03 Wed	92	—	unknown	19:15–00:25 (good, 5.17 h)	72.6° 19:15	10.7	22%	48.4°
2044-02-04 Thu	83	—	unknown	19:15–00:25 (good, 5.17 h)	72.5° 19:10	10.67	32%	34.9°
2044-02-05 Fri	69	—	unknown	19:20–00:00 (good, 4.67 h)	72.6° 19:10	10.63	43%	21.1°
2044-02-06 Sat	50	—	unknown	20:20–22:00 (good, 1.67 h)	72.6° 19:05	10.6	54%	7.2°
2044-02-07 Sun	33	—	unknown	19:20–00:25 (marginal, 5.08 h)	72.6° 19:00	10.56	65%	7.1°
2044-02-08 Mon	21	—	unknown	19:20–00:05 (marginal, 4.75 h)	72.6° 18:55	10.53	76%	21.4°
2044-02-09 Tue	18	—	unknown	19:25–23:45 (marginal, 4.33 h)	72.5° 18:50	10.49	85%	35.9°
2044-02-10 Wed	23	—	unknown	19:25–23:45 (marginal, 4.33 h)	72.6° 18:50	10.45	92%	50.5°
2044-02-11 Thu	34	—	unknown	19:25–23:50 (marginal, 4.42 h)	72.6° 18:45	10.42	98%	65.1°
2044-02-12 Fri	49	—	unknown	19:25–21:10 (good, 1.75 h)	72.6° 18:40	10.38	100%	79.5°
2044-02-13 Sat	66	—	unknown	19:25–22:40 (good, 3.25 h)	72.6° 18:35	10.34	99%	93.6°
2044-02-14 Sun	82	—	unknown	19:30–23:25 (good, 3.92 h)	72.5° 18:35	10.3	96%	107.5°
2044-02-15 Mon	100	—	unknown	19:30–23:30 (good, 4.0 h)	72.6° 18:30	10.26	92%	121.0°
2044-02-16 Tue	100	—	unknown	19:30–23:30 (good, 4.0 h)	72.6° 18:25	10.22	85%	134.1°
2044-02-17 Wed	100	—	unknown	19:30–23:25 (good, 3.92 h)	72.6° 18:20	10.18	77%	146.8°
2044-02-18 Thu	100	—	unknown	19:35–23:30 (good, 3.92 h)	72.6° 18:15	10.14	68%	159.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-01-20&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.