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: 05-10 (84), 05-11 (84), 05-12 (84), 05-13 (84), 05-08 (83) — by astronomy; check the weather when the night is within four days.

2030-04-22astronomy score per night — click a bar for that night2030-05-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-04-22 Mon	31	—	unknown	03:35–04:50 (good, 1.25 h)	71.1° 07:20	6.89	70%	48.2°
2030-04-23 Tue	36	—	unknown	02:35–04:45 (good, 2.17 h)	71.1° 07:15	6.83	59%	41.6°
2030-04-24 Wed	48	—	unknown	02:10–04:45 (good, 2.58 h)	71.1° 07:10	6.77	48%	38.3°
2030-04-25 Thu	55	—	unknown	02:05–04:45 (good, 2.67 h)	71.1° 07:05	6.71	38%	38.9°
2030-04-26 Fri	61	—	unknown	02:00–04:40 (good, 2.67 h)	71.1° 07:00	6.65	28%	42.9°
2030-04-27 Sat	67	—	unknown	01:55–04:40 (good, 2.75 h)	71.1° 07:00	6.59	20%	49.3°
2030-04-28 Sun	71	—	unknown	01:55–04:35 (good, 2.67 h)	71.1° 06:55	6.54	12%	57.2°
2030-04-29 Mon	73	—	unknown	01:50–04:35 (good, 2.75 h)	71.1° 06:50	6.48	7%	65.9°
2030-04-30 Tue	74	—	unknown	01:45–04:35 (good, 2.83 h)	71.1° 06:45	6.42	3%	75.1°
2030-05-01 Wed	74	—	unknown	01:40–04:30 (good, 2.83 h)	71.1° 06:45	6.36	0%	84.4°
2030-05-02 Thu	76	—	unknown	01:35–04:30 (good, 2.92 h)	71.1° 06:40	6.3	0%	93.7°
2030-05-03 Fri	78	—	unknown	01:35–04:30 (good, 2.92 h)	71.1° 06:35	6.25	2%	103.0°
2030-05-04 Sat	78	—	unknown	01:30–04:25 (good, 2.92 h)	71.1° 06:30	6.19	5%	112.0°
2030-05-05 Sun	79	—	unknown	01:25–04:25 (good, 3.0 h)	71.1° 06:25	6.13	10%	120.6°
2030-05-06 Mon	80	—	unknown	01:20–04:20 (good, 3.0 h)	71.1° 06:25	6.07	16%	128.5°
2030-05-07 Tue	82	—	unknown	01:20–04:20 (good, 3.0 h)	71.1° 06:20	6.02	24%	135.2°
2030-05-08 Wed	83	—	unknown	01:15–04:20 (good, 3.08 h)	71.1° 06:15	5.96	32%	140.0°
2030-05-09 Thu	83	—	unknown	01:15–04:15 (good, 3.0 h)	71.1° 06:10	5.9	42%	142.0°
2030-05-10 Fri	84	—	unknown	01:10–04:15 (good, 3.08 h)	71.1° 06:05	5.85	52%	140.6°
2030-05-11 Sat	84	—	unknown	01:10–04:15 (good, 3.08 h)	71.1° 06:05	5.79	63%	135.8°
2030-05-12 Sun	84	—	unknown	01:05–04:10 (good, 3.08 h)	71.1° 06:00	5.74	73%	128.3°
2030-05-13 Mon	84	—	unknown	01:05–04:10 (good, 3.08 h)	71.1° 05:55	5.68	82%	118.8°
2030-05-14 Tue	70	—	unknown	01:05–04:10 (good, 3.08 h)	71.1° 05:50	5.63	90%	108.1°
2030-05-15 Wed	59	—	unknown	01:10–04:05 (good, 2.92 h)	71.1° 05:50	5.58	96%	96.5°
2030-05-16 Thu	50	—	unknown	01:50–04:05 (good, 2.25 h)	71.1° 05:45	5.52	100%	84.6°
2030-05-17 Fri	42	—	unknown	02:45–04:05 (good, 1.33 h)	71.1° 05:40	5.47	100%	72.7°
2030-05-18 Sat	35	—	unknown	03:35–04:00 (good, 0.42 h)	71.1° 05:35	5.42	97%	61.4°
2030-05-19 Sun	33	—	unknown	00:10–04:00 (marginal, 3.83 h)	71.1° 05:30	5.37	91%	51.4°
2030-05-20 Mon	34	—	unknown	00:00–04:00 (marginal, 4.0 h)	71.1° 05:30	5.32	83%	43.4°
2030-05-21 Tue	51	—	unknown	02:25–04:00 (good, 1.58 h)	71.1° 05:25	5.27	74%	38.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-04-22&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.