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: 01-25 (100), 01-26 (100), 01-27 (100), 02-11 (100), 02-12 (100) — by astronomy; check the weather when the night is within four days.

2039-01-25astronomy score per night — click a bar for that night2039-02-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-01-25 Tue	100	—	unknown	19:05–01:00 (good, 5.92 h)	72.5° 19:50	10.98	2%	96.7°
2039-01-26 Wed	100	—	unknown	19:05–00:55 (good, 5.83 h)	72.5° 19:45	10.95	7%	83.4°
2039-01-27 Thu	100	—	unknown	19:10–00:55 (good, 5.75 h)	72.5° 19:40	10.92	13%	70.4°
2039-01-28 Fri	99	—	unknown	19:10–00:50 (good, 5.67 h)	72.5° 19:40	10.89	20%	57.8°
2039-01-29 Sat	91	—	unknown	19:10–00:45 (good, 5.58 h)	72.5° 19:35	10.86	29%	45.6°
2039-01-30 Sun	83	—	unknown	19:10–00:40 (good, 5.5 h)	72.5° 19:30	10.83	38%	33.7°
2039-01-31 Mon	70	—	unknown	19:15–00:15 (good, 5.0 h)	72.5° 19:25	10.79	48%	22.2°
2039-02-01 Tue	52	—	unknown	21:05–21:55 (good, 0.83 h)	72.5° 19:25	10.76	57%	11.5°
2039-02-02 Wed	37	—	unknown	19:15–00:50 (marginal, 5.58 h)	72.5° 19:20	10.73	66%	7.2°
2039-02-03 Thu	26	—	unknown	19:15–00:30 (marginal, 5.25 h)	72.5° 19:15	10.7	75%	15.9°
2039-02-04 Fri	19	—	unknown	19:15–00:05 (marginal, 4.83 h)	72.5° 19:10	10.66	83%	27.3°
2039-02-05 Sat	20	—	unknown	19:20–23:55 (marginal, 4.58 h)	72.5° 19:05	10.63	89%	39.3°
2039-02-06 Sun	26	—	unknown	19:20–23:55 (marginal, 4.58 h)	72.5° 19:05	10.59	95%	51.7°
2039-02-07 Mon	36	—	unknown	19:20–00:05 (marginal, 4.75 h)	72.5° 19:00	10.56	98%	64.4°
2039-02-08 Tue	51	—	unknown	19:20–21:10 (good, 1.83 h)	72.5° 18:55	10.52	100%	77.4°
2039-02-09 Wed	67	—	unknown	19:25–22:35 (good, 3.17 h)	72.5° 18:50	10.48	99%	90.8°
2039-02-10 Thu	86	—	unknown	19:25–23:35 (good, 4.17 h)	72.5° 18:45	10.45	96%	104.3°
2039-02-11 Fri	100	—	unknown	19:25–23:45 (good, 4.33 h)	72.5° 18:45	10.41	91%	118.1°
2039-02-12 Sat	100	—	unknown	19:25–23:40 (good, 4.25 h)	72.5° 18:40	10.37	83%	131.9°
2039-02-13 Sun	100	—	unknown	19:25–23:40 (good, 4.25 h)	72.5° 18:35	10.33	74%	145.8°
2039-02-14 Mon	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:30	10.29	63%	159.4°
2039-02-15 Tue	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:30	10.25	52%	171.4°
2039-02-16 Wed	100	—	unknown	19:30–23:35 (good, 4.08 h)	72.5° 18:25	10.21	41%	169.1°
2039-02-17 Thu	100	—	unknown	19:30–23:30 (good, 4.0 h)	72.5° 18:20	10.17	30%	156.3°
2039-02-18 Fri	100	—	unknown	19:35–23:25 (good, 3.83 h)	72.5° 18:15	10.13	20%	142.7°
2039-02-19 Sat	100	—	unknown	19:35–23:25 (good, 3.83 h)	72.5° 18:10	10.09	12%	128.9°
2039-02-20 Sun	97	—	unknown	19:35–23:20 (good, 3.75 h)	72.5° 18:10	10.05	6%	115.2°
2039-02-21 Mon	95	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:05	10.01	2%	101.7°
2039-02-22 Tue	93	—	unknown	19:40–23:10 (good, 3.5 h)	72.5° 18:00	9.96	0%	88.4°
2039-02-23 Wed	91	—	unknown	19:40–23:05 (good, 3.42 h)	72.5° 17:55	9.92	1%	75.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-01-25&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.