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: 04-06 (5), 04-07 (3), 04-08 (2), 04-09 (1), 04-10 (1) — by astronomy; check the weather when the night is within four days.

2038-04-06astronomy score per night — click a bar for that night2038-05-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-04-06 Tue	5	—	unknown	21:30–21:50 (marginal, 0.33 h)	72.5° 16:10	7.8	5%	20.1°
2038-04-07 Wed	3	—	unknown	21:00–21:15 (marginal, 0.25 h)	72.5° 16:05	7.74	9%	10.2°
2038-04-08 Thu	2	—	unknown	21:35–21:40 (marginal, 0.08 h)	72.5° 16:00	7.69	16%	9.2°
2038-04-09 Fri	1	—	unknown	—	72.5° 16:00	7.63	23%	18.9°
2038-04-10 Sat	1	—	unknown	—	72.5° 15:55	7.57	32%	30.5°
2038-04-11 Sun	1	—	unknown	—	72.5° 15:50	7.52	42%	42.8°
2038-04-12 Mon	0	—	unknown	—	72.5° 15:45	7.46	52%	55.5°
2038-04-13 Tue	0	—	unknown	—	72.5° 15:40	7.4	62%	68.7°
2038-04-14 Wed	0	—	unknown	—	72.5° 15:40	7.35	73%	82.4°
2038-04-15 Thu	0	—	unknown	—	72.5° 15:35	7.29	82%	96.5°
2038-04-16 Fri	0	—	unknown	—	72.5° 15:30	7.23	90%	111.0°
2038-04-17 Sat	0	—	unknown	—	72.5° 15:25	7.17	96%	125.9°
2038-04-18 Sun	0	—	unknown	—	72.5° 15:25	7.11	99%	140.9°
2038-04-19 Mon	0	—	unknown	—	72.5° 15:20	7.06	100%	155.6°
2038-04-20 Tue	0	—	unknown	—	72.5° 15:15	7.0	96%	168.9°
2038-04-21 Wed	0	—	unknown	—	72.5° 15:10	6.94	91%	169.9°
2038-04-22 Thu	0	—	unknown	—	72.5° 15:05	6.88	83%	157.5°
2038-04-23 Fri	0	—	unknown	—	72.5° 15:05	6.82	74%	144.1°
2038-04-24 Sat	0	—	unknown	—	72.5° 15:00	6.77	64%	130.8°
2038-04-25 Sun	0	—	unknown	—	72.5° 14:55	6.71	53%	117.9°
2038-04-26 Mon	0	—	unknown	—	72.5° 14:50	6.65	43%	105.4°
2038-04-27 Tue	0	—	unknown	—	72.5° 14:45	6.59	34%	93.1°
2038-04-28 Wed	0	—	unknown	—	72.5° 14:45	6.53	25%	81.1°
2038-04-29 Thu	0	—	unknown	—	72.5° 14:40	6.47	17%	69.2°
2038-04-30 Fri	0	—	unknown	—	72.5° 14:35	6.42	11%	57.5°
2038-05-01 Sat	0	—	unknown	—	72.5° 14:30	6.36	6%	45.8°
2038-05-02 Sun	0	—	unknown	—	72.5° 14:30	6.3	2%	34.3°
2038-05-03 Mon	0	—	unknown	—	72.5° 14:25	6.24	0%	22.9°
2038-05-04 Tue	0	—	unknown	—	72.5° 14:20	6.19	0%	12.3°
2038-05-05 Wed	0	—	unknown	—	72.5° 14:15	6.13	2%	7.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-04-06&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.