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: 12-31 (9), 01-01 (8), 01-02 (7), 01-03 (6), 01-04 (5) — by astronomy; check the weather when the night is within four days.

2034-12-31astronomy score per night — click a bar for that night2035-01-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-12-31 Sun	9	—	unknown	18:45–18:50 (good, 0.08 h)	71.1° 13:45	11.46	55%	113.3°
2035-01-01 Mon	8	—	unknown	18:10–19:15 (marginal, 1.08 h)	71.1° 13:40	11.45	45%	104.1°
2035-01-02 Tue	7	—	unknown	18:45–19:10 (marginal, 0.42 h)	71.1° 13:35	11.44	36%	94.7°
2035-01-03 Wed	6	—	unknown	18:10–18:40 (marginal, 0.5 h)	71.1° 13:30	11.43	27%	85.5°
2035-01-04 Thu	5	—	unknown	18:10–18:35 (marginal, 0.42 h)	71.1° 13:30	11.42	19%	76.3°
2035-01-05 Fri	3	—	unknown	18:15–18:30 (marginal, 0.25 h)	71.1° 13:25	11.4	12%	67.5°
2035-01-06 Sat	3	—	unknown	18:15–18:25 (marginal, 0.17 h)	71.1° 13:20	11.39	7%	59.1°
2035-01-07 Sun	2	—	unknown	18:15–18:20 (marginal, 0.08 h)	71.1° 13:15	11.38	3%	51.5°
2035-01-08 Mon	1	—	unknown	18:15–18:20 (marginal, 0.08 h)	71.1° 13:10	11.36	1%	45.1°
2035-01-09 Tue	1	—	unknown	—	71.1° 13:10	11.34	0%	40.6°
2035-01-10 Wed	1	—	unknown	—	71.1° 13:05	11.33	2%	39.0°
2035-01-11 Thu	1	—	unknown	—	71.1° 13:00	11.31	5%	40.6°
2035-01-12 Fri	0	—	unknown	—	71.1° 12:55	11.29	11%	45.2°
2035-01-13 Sat	0	—	unknown	—	71.1° 12:50	11.27	18%	52.2°
2035-01-14 Sun	0	—	unknown	—	71.1° 12:50	11.25	26%	60.8°
2035-01-15 Mon	0	—	unknown	—	71.1° 12:45	11.23	36%	70.4°
2035-01-16 Tue	0	—	unknown	—	71.1° 12:40	11.21	47%	80.8°
2035-01-17 Wed	0	—	unknown	—	71.1° 12:35	11.18	58%	91.6°
2035-01-18 Thu	0	—	unknown	—	71.1° 12:35	11.16	69%	102.5°
2035-01-19 Fri	0	—	unknown	—	71.1° 12:30	11.14	80%	113.4°
2035-01-20 Sat	0	—	unknown	—	71.1° 12:25	11.11	88%	123.6°
2035-01-21 Sun	0	—	unknown	—	71.1° 12:20	11.09	95%	132.4°
2035-01-22 Mon	0	—	unknown	—	71.1° 12:15	11.06	99%	138.6°
2035-01-23 Tue	0	—	unknown	—	71.1° 12:15	11.03	100%	141.0°
2035-01-24 Wed	0	—	unknown	—	71.1° 12:10	11.01	98%	138.9°
2035-01-25 Thu	0	—	unknown	—	71.1° 12:05	10.98	94%	133.3°
2035-01-26 Fri	0	—	unknown	—	71.1° 12:00	10.95	88%	125.5°
2035-01-27 Sat	0	—	unknown	—	71.1° 11:55	10.92	81%	116.5°
2035-01-28 Sun	0	—	unknown	—	71.1° 11:50	10.89	72%	107.1°
2035-01-29 Mon	1	—	unknown	—	71.1° 11:45	10.86	63%	97.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-12-31&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.