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 (6), 04-07 (4), 04-08 (3), 04-09 (3), 04-10 (2) — by astronomy; check the weather when the night is within four days.

2043-04-06astronomy score per night — click a bar for that night2043-05-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-04-06 Mon	6	—	unknown	21:30–21:50 (marginal, 0.33 h)	72.6° 16:10	7.81	11%	82.1°
2043-04-07 Tue	4	—	unknown	20:55–21:20 (marginal, 0.42 h)	72.5° 16:05	7.76	5%	67.8°
2043-04-08 Wed	3	—	unknown	21:00–21:15 (marginal, 0.25 h)	72.5° 16:05	7.7	1%	53.0°
2043-04-09 Thu	3	—	unknown	21:00–21:10 (marginal, 0.17 h)	72.6° 16:00	7.64	0%	37.9°
2043-04-10 Fri	2	—	unknown	21:00–21:05 (marginal, 0.08 h)	72.6° 15:55	7.59	2%	22.8°
2043-04-11 Sat	1	—	unknown	—	72.5° 15:50	7.53	7%	7.7°
2043-04-12 Sun	1	—	unknown	—	72.5° 15:50	7.47	14%	7.2°
2043-04-13 Mon	1	—	unknown	—	72.5° 15:45	7.41	23%	21.8°
2043-04-14 Tue	0	—	unknown	—	72.6° 15:40	7.36	34%	36.0°
2043-04-15 Wed	0	—	unknown	—	72.6° 15:35	7.3	45%	49.7°
2043-04-16 Thu	0	—	unknown	—	72.5° 15:30	7.24	55%	63.1°
2043-04-17 Fri	0	—	unknown	—	72.5° 15:30	7.18	66%	76.2°
2043-04-18 Sat	0	—	unknown	—	72.6° 15:25	7.13	75%	88.9°
2043-04-19 Sun	0	—	unknown	—	72.6° 15:20	7.07	83%	101.4°
2043-04-20 Mon	0	—	unknown	—	72.6° 15:15	7.01	90%	113.7°
2043-04-21 Tue	0	—	unknown	—	72.5° 15:10	6.95	95%	125.8°
2043-04-22 Wed	0	—	unknown	—	72.5° 15:10	6.89	98%	137.8°
2043-04-23 Thu	0	—	unknown	—	72.6° 15:05	6.84	100%	149.8°
2043-04-24 Fri	0	—	unknown	—	72.6° 15:00	6.78	100%	161.6°
2043-04-25 Sat	0	—	unknown	—	72.5° 14:55	6.72	98%	173.5°
2043-04-26 Sun	0	—	unknown	—	72.5° 14:55	6.66	94%	174.7°
2043-04-27 Mon	0	—	unknown	—	72.5° 14:50	6.6	88%	162.8°
2043-04-28 Tue	0	—	unknown	—	72.6° 14:45	6.54	82%	150.8°
2043-04-29 Wed	0	—	unknown	—	72.6° 14:40	6.49	74%	138.7°
2043-04-30 Thu	0	—	unknown	—	72.5° 14:35	6.43	64%	126.4°
2043-05-01 Fri	0	—	unknown	—	72.5° 14:35	6.37	55%	113.8°
2043-05-02 Sat	0	—	unknown	—	72.6° 14:30	6.31	44%	100.9°
2043-05-03 Sun	0	—	unknown	—	72.6° 14:25	6.25	34%	87.6°
2043-05-04 Mon	0	—	unknown	—	72.6° 14:20	6.2	24%	73.8°
2043-05-05 Tue	0	—	unknown	—	72.5° 14:15	6.14	15%	59.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-04-06&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.