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: 02-16 (10), 02-15 (9), 02-14 (8), 02-12 (7), 02-13 (7) — by astronomy; check the weather when the night is within four days.

2035-01-18astronomy score per night — click a bar for that night2035-02-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2035-01-30 Tue	1	—	unknown	—	71.1° 11:40	10.83	53%	88.2°
2035-01-31 Wed	1	—	unknown	—	71.1° 11:40	10.8	44%	79.0°
2035-02-01 Thu	1	—	unknown	—	71.1° 11:35	10.76	34%	70.0°
2035-02-02 Fri	1	—	unknown	—	71.1° 11:30	10.73	26%	61.5°
2035-02-03 Sat	2	—	unknown	05:55–06:00 (marginal, 0.08 h)	71.1° 11:25	10.7	18%	53.6°
2035-02-04 Sun	2	—	unknown	06:25–06:30 (marginal, 0.08 h)	71.1° 11:20	10.66	11%	46.8°
2035-02-05 Mon	3	—	unknown	06:20–06:30 (marginal, 0.17 h)	71.1° 11:20	10.63	6%	41.7°
2035-02-06 Tue	3	—	unknown	06:15–06:30 (marginal, 0.25 h)	71.1° 11:15	10.59	2%	39.1°
2035-02-07 Wed	4	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:10	10.56	0%	39.8°
2035-02-08 Thu	4	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:05	10.52	0%	43.8°
2035-02-09 Fri	5	—	unknown	06:00–06:25 (marginal, 0.42 h)	71.1° 11:00	10.48	3%	50.3°
2035-02-10 Sat	6	—	unknown	05:55–06:25 (marginal, 0.5 h)	71.1° 11:00	10.45	7%	58.7°
2035-02-11 Sun	6	—	unknown	05:25–05:50 (marginal, 0.42 h)	71.1° 10:55	10.41	14%	68.3°
2035-02-12 Mon	7	—	unknown	05:20–06:20 (marginal, 1.0 h)	71.1° 10:50	10.37	22%	78.5°
2035-02-13 Tue	7	—	unknown	05:20–06:20 (marginal, 1.0 h)	71.1° 10:45	10.33	32%	89.2°
2035-02-14 Wed	8	—	unknown	05:40–05:45 (good, 0.08 h)	71.1° 10:45	10.29	43%	100.0°
2035-02-15 Thu	9	—	unknown	05:35–05:45 (good, 0.17 h)	71.1° 10:40	10.25	54%	110.7°
2035-02-16 Fri	10	—	unknown	05:35–05:45 (good, 0.17 h)	71.1° 10:35	10.21	66%	120.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-01-18&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.