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 HD 189733: 02-10 (5), 02-09 (4), 02-07 (3), 02-08 (3), 02-05 (2) — by astronomy; check the weather when the night is within four days.

2048-01-12astronomy score per night — click a bar for that night2048-02-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2048-01-12 Sun	1	—	unknown	—	71.1° 12:55	11.29	9%	63.4°
2048-01-13 Mon	0	—	unknown	—	71.2° 12:55	11.27	3%	53.6°
2048-01-14 Tue	0	—	unknown	—	71.2° 12:50	11.25	0%	45.6°
2048-01-15 Wed	0	—	unknown	—	71.2° 12:45	11.23	0%	40.5°
2048-01-16 Thu	0	—	unknown	—	71.2° 12:40	11.21	3%	39.3°
2048-01-17 Fri	0	—	unknown	—	71.1° 12:40	11.19	8%	42.2°
2048-01-18 Sat	0	—	unknown	—	71.2° 12:35	11.16	14%	48.1°
2048-01-19 Sun	0	—	unknown	—	71.2° 12:30	11.14	22%	55.7°
2048-01-20 Mon	0	—	unknown	—	71.2° 12:25	11.12	31%	64.3°
2048-01-21 Tue	0	—	unknown	—	71.1° 12:20	11.09	41%	73.3°
2048-01-22 Wed	0	—	unknown	—	71.1° 12:20	11.06	50%	82.5°
2048-01-23 Thu	0	—	unknown	—	71.2° 12:15	11.04	60%	91.7°
2048-01-24 Fri	0	—	unknown	—	71.2° 12:10	11.01	69%	100.8°
2048-01-25 Sat	0	—	unknown	—	71.2° 12:05	10.98	77%	109.7°
2048-01-26 Sun	0	—	unknown	—	71.2° 12:00	10.95	84%	118.3°
2048-01-27 Mon	0	—	unknown	—	71.2° 11:55	10.92	91%	126.3°
2048-01-28 Tue	1	—	unknown	—	71.2° 11:50	10.89	96%	133.2°
2048-01-29 Wed	1	—	unknown	—	71.2° 11:45	10.86	99%	138.3°
2048-01-30 Thu	1	—	unknown	—	71.1° 11:45	10.83	100%	140.7°
2048-01-31 Fri	1	—	unknown	—	71.2° 11:40	10.8	99%	139.6°
2048-02-01 Sat	1	—	unknown	—	71.2° 11:35	10.77	96%	135.1°
2048-02-02 Sun	1	—	unknown	—	71.2° 11:30	10.74	90%	128.0°
2048-02-03 Mon	1	—	unknown	—	71.1° 11:25	10.7	83%	119.2°
2048-02-04 Tue	1	—	unknown	—	71.1° 11:25	10.67	74%	109.3°
2048-02-05 Wed	2	—	unknown	05:50–05:55 (marginal, 0.08 h)	71.2° 11:20	10.63	63%	98.8°
2048-02-06 Thu	2	—	unknown	05:45–05:55 (marginal, 0.17 h)	71.2° 11:15	10.6	52%	87.9°
2048-02-07 Fri	3	—	unknown	05:45–05:55 (marginal, 0.17 h)	71.2° 11:10	10.56	41%	77.0°
2048-02-08 Sat	3	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:05	10.53	30%	66.5°
2048-02-09 Sun	4	—	unknown	05:35–05:50 (marginal, 0.25 h)	71.2° 11:05	10.49	20%	56.6°
2048-02-10 Mon	5	—	unknown	05:30–05:50 (marginal, 0.33 h)	71.2° 11:00	10.45	12%	48.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-01-12&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.