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: 02-17 (11), 02-16 (10), 02-15 (9), 02-14 (8), 02-12 (7) — by astronomy; check the weather when the night is within four days.

2043-01-19astronomy score per night — click a bar for that night2043-02-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-01-19 Mon	0	—	unknown	—	71.1° 12:30	11.14	67%	96.3°
2043-01-20 Tue	0	—	unknown	—	71.1° 12:25	11.11	78%	105.8°
2043-01-21 Wed	0	—	unknown	—	71.1° 12:20	11.09	86%	114.7°
2043-01-22 Thu	0	—	unknown	—	71.1° 12:15	11.06	93%	122.6°
2043-01-23 Fri	0	—	unknown	—	71.1° 12:15	11.03	98%	128.7°
2043-01-24 Sat	0	—	unknown	—	71.1° 12:10	11.0	100%	132.5°
2043-01-25 Sun	0	—	unknown	—	71.1° 12:05	10.98	99%	133.4°
2043-01-26 Mon	0	—	unknown	—	71.1° 12:00	10.95	97%	131.4°
2043-01-27 Tue	0	—	unknown	—	71.1° 11:55	10.92	92%	127.1°
2043-01-28 Wed	1	—	unknown	—	71.1° 11:50	10.89	86%	121.1°
2043-01-29 Thu	1	—	unknown	—	71.1° 11:45	10.86	79%	114.1°
2043-01-30 Fri	1	—	unknown	—	71.1° 11:40	10.83	70%	106.5°
2043-01-31 Sat	1	—	unknown	—	71.1° 11:40	10.79	62%	98.6°
2043-02-01 Sun	1	—	unknown	—	71.1° 11:35	10.76	52%	90.5°
2043-02-02 Mon	1	—	unknown	—	71.1° 11:30	10.73	43%	82.4°
2043-02-03 Tue	2	—	unknown	05:55–06:00 (marginal, 0.08 h)	71.1° 11:25	10.69	34%	74.4°
2043-02-04 Wed	2	—	unknown	—	71.1° 11:20	10.66	25%	66.7°
2043-02-05 Thu	2	—	unknown	06:20–06:30 (marginal, 0.17 h)	71.1° 11:20	10.63	17%	59.5°
2043-02-06 Fri	3	—	unknown	05:45–05:55 (marginal, 0.17 h)	71.1° 11:15	10.59	10%	53.3°
2043-02-07 Sat	4	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:10	10.55	5%	48.8°
2043-02-08 Sun	4	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:05	10.52	1%	46.7°
2043-02-09 Mon	5	—	unknown	06:00–06:25 (marginal, 0.42 h)	71.1° 11:00	10.48	0%	47.5°
2043-02-10 Tue	6	—	unknown	05:55–06:25 (marginal, 0.5 h)	71.1° 11:00	10.44	2%	51.3°
2043-02-11 Wed	6	—	unknown	05:25–05:50 (marginal, 0.42 h)	71.1° 10:55	10.41	5%	57.6°
2043-02-12 Thu	7	—	unknown	05:20–06:20 (marginal, 1.0 h)	71.1° 10:50	10.37	12%	65.6°
2043-02-13 Fri	7	—	unknown	05:20–06:20 (marginal, 1.0 h)	71.1° 10:45	10.33	20%	74.6°
2043-02-14 Sat	8	—	unknown	05:40–05:45 (good, 0.08 h)	71.1° 10:45	10.29	30%	84.3°
2043-02-15 Sun	9	—	unknown	05:35–05:45 (good, 0.17 h)	71.1° 10:40	10.25	41%	94.0°
2043-02-16 Mon	10	—	unknown	05:35–05:45 (good, 0.17 h)	71.1° 10:35	10.21	53%	103.6°
2043-02-17 Tue	11	—	unknown	05:30–05:40 (good, 0.17 h)	71.1° 10:30	10.17	64%	112.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-01-19&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.