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: 05-05 (78), 05-04 (77), 05-01 (76), 05-02 (76), 05-03 (76) — by astronomy; check the weather when the night is within four days.

2044-04-09astronomy score per night — click a bar for that night2044-05-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-04-09 Sat	45	—	unknown	03:15–05:15 (good, 2.0 h)	71.1° 08:05	7.6	94%	123.2°
2044-04-10 Sun	42	—	unknown	03:15–05:10 (good, 1.92 h)	71.1° 08:05	7.54	98%	115.7°
2044-04-11 Mon	40	—	unknown	03:15–05:10 (good, 1.92 h)	71.1° 08:00	7.49	100%	107.5°
2044-04-12 Tue	36	—	unknown	03:20–05:05 (good, 1.75 h)	71.1° 07:55	7.43	100%	98.9°
2044-04-13 Wed	33	—	unknown	03:25–05:05 (good, 1.67 h)	71.1° 07:50	7.37	98%	90.2°
2044-04-14 Thu	31	—	unknown	03:45–05:05 (good, 1.33 h)	71.1° 07:50	7.31	94%	81.6°
2044-04-15 Fri	30	—	unknown	03:50–05:00 (good, 1.17 h)	71.1° 07:45	7.26	88%	73.3°
2044-04-16 Sat	30	—	unknown	03:40–05:00 (good, 1.33 h)	71.1° 07:40	7.2	81%	65.6°
2044-04-17 Sun	32	—	unknown	03:10–04:55 (good, 1.75 h)	71.1° 07:35	7.14	73%	58.6°
2044-04-18 Mon	35	—	unknown	02:55–04:55 (good, 2.0 h)	71.1° 07:30	7.08	65%	52.7°
2044-04-19 Tue	46	—	unknown	02:25–04:55 (good, 2.5 h)	71.1° 07:30	7.02	55%	48.2°
2044-04-20 Wed	52	—	unknown	02:25–04:50 (good, 2.42 h)	71.1° 07:25	6.97	46%	45.8°
2044-04-21 Thu	58	—	unknown	02:20–04:50 (good, 2.5 h)	71.1° 07:20	6.91	36%	45.7°
2044-04-22 Fri	62	—	unknown	02:15–04:45 (good, 2.5 h)	71.1° 07:15	6.85	27%	48.2°
2044-04-23 Sat	66	—	unknown	02:10–04:45 (good, 2.58 h)	71.1° 07:10	6.79	18%	53.2°
2044-04-24 Sun	68	—	unknown	02:05–04:45 (good, 2.67 h)	71.1° 07:10	6.73	11%	60.1°
2044-04-25 Mon	69	—	unknown	02:05–04:40 (good, 2.58 h)	71.1° 07:05	6.67	5%	68.5°
2044-04-26 Tue	71	—	unknown	02:00–04:40 (good, 2.67 h)	71.1° 07:00	6.62	1%	78.0°
2044-04-27 Wed	71	—	unknown	01:55–04:40 (good, 2.75 h)	71.1° 06:55	6.56	0%	88.1°
2044-04-28 Thu	72	—	unknown	01:50–04:35 (good, 2.75 h)	71.1° 06:55	6.5	2%	98.4°
2044-04-29 Fri	74	—	unknown	01:45–04:35 (good, 2.83 h)	71.1° 06:50	6.44	6%	108.5°
2044-04-30 Sat	74	—	unknown	01:45–04:30 (good, 2.75 h)	71.1° 06:45	6.38	14%	117.9°
2044-05-01 Sun	76	—	unknown	01:40–04:30 (good, 2.83 h)	71.1° 06:40	6.33	23%	125.8°
2044-05-02 Mon	76	—	unknown	01:40–04:30 (good, 2.83 h)	71.1° 06:35	6.27	33%	131.6°
2044-05-03 Tue	76	—	unknown	01:35–04:25 (good, 2.83 h)	71.1° 06:35	6.21	44%	134.4°
2044-05-04 Wed	77	—	unknown	01:35–04:25 (good, 2.83 h)	71.1° 06:30	6.15	56%	134.0°
2044-05-05 Thu	78	—	unknown	01:30–04:25 (good, 2.92 h)	71.1° 06:25	6.1	66%	130.6°
2044-05-06 Fri	76	—	unknown	01:30–04:20 (good, 2.83 h)	71.1° 06:20	6.04	76%	124.9°
2044-05-07 Sat	76	—	unknown	01:25–04:20 (good, 2.92 h)	71.1° 06:15	5.98	84%	117.8°
2044-05-08 Sun	66	—	unknown	01:25–04:20 (good, 2.92 h)	71.1° 06:15	5.93	91%	109.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-04-09&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.