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: 04-17 (59), 04-14 (58), 04-15 (58), 04-16 (58), 04-18 (58) — by astronomy; check the weather when the night is within four days.

2043-04-02astronomy score per night — click a bar for that night2043-05-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-04-02 Thu	33	—	unknown	03:35–05:30 (good, 1.92 h)	71.1° 08:40	8.03	49%	52.2°
2043-04-03 Fri	41	—	unknown	03:35–05:25 (good, 1.83 h)	71.1° 08:35	7.98	38%	48.3°
2043-04-04 Sat	46	—	unknown	03:30–05:25 (good, 1.92 h)	71.1° 08:30	7.92	29%	46.7°
2043-04-05 Sun	49	—	unknown	03:25–05:20 (good, 1.92 h)	71.1° 08:25	7.87	19%	47.9°
2043-04-06 Mon	50	—	unknown	03:20–05:20 (good, 2.0 h)	71.1° 08:20	7.81	11%	52.0°
2043-04-07 Tue	52	—	unknown	03:15–05:20 (good, 2.08 h)	71.1° 08:20	7.76	5%	58.6°
2043-04-08 Wed	52	—	unknown	03:15–05:15 (good, 2.0 h)	71.1° 08:15	7.7	1%	67.1°
2043-04-09 Thu	54	—	unknown	03:10–05:15 (good, 2.08 h)	71.1° 08:10	7.64	0%	76.7°
2043-04-10 Fri	53	—	unknown	03:05–05:10 (good, 2.08 h)	71.1° 08:05	7.59	2%	87.0°
2043-04-11 Sat	55	—	unknown	03:00–05:10 (good, 2.17 h)	71.1° 08:00	7.53	7%	97.3°
2043-04-12 Sun	56	—	unknown	02:55–05:10 (good, 2.25 h)	71.1° 08:00	7.47	14%	107.3°
2043-04-13 Mon	56	—	unknown	02:55–05:05 (good, 2.17 h)	71.1° 07:55	7.41	23%	116.3°
2043-04-14 Tue	58	—	unknown	02:50–05:05 (good, 2.25 h)	71.1° 07:50	7.36	34%	123.9°
2043-04-15 Wed	58	—	unknown	02:50–05:00 (good, 2.17 h)	71.1° 07:45	7.3	45%	129.6°
2043-04-16 Thu	58	—	unknown	02:45–05:00 (good, 2.25 h)	71.1° 07:45	7.24	55%	132.7°
2043-04-17 Fri	59	—	unknown	02:45–05:00 (good, 2.25 h)	71.1° 07:40	7.18	66%	133.2°
2043-04-18 Sat	58	—	unknown	02:40–04:55 (good, 2.25 h)	71.1° 07:35	7.13	75%	130.9°
2043-04-19 Sun	54	—	unknown	02:40–04:55 (good, 2.25 h)	71.1° 07:30	7.07	83%	126.5°
2043-04-20 Mon	52	—	unknown	02:35–04:50 (good, 2.25 h)	71.1° 07:25	7.01	90%	120.6°
2043-04-21 Tue	50	—	unknown	02:35–04:50 (good, 2.25 h)	71.1° 07:25	6.95	95%	113.6°
2043-04-22 Wed	46	—	unknown	02:35–04:50 (good, 2.25 h)	71.1° 07:20	6.89	98%	106.0°
2043-04-23 Thu	41	—	unknown	02:40–04:45 (good, 2.08 h)	71.1° 07:15	6.84	100%	98.1°
2043-04-24 Fri	38	—	unknown	02:55–04:45 (good, 1.83 h)	71.1° 07:10	6.78	100%	89.9°
2043-04-25 Sat	35	—	unknown	03:15–04:45 (good, 1.5 h)	71.1° 07:05	6.72	98%	81.9°
2043-04-26 Sun	33	—	unknown	03:30–04:40 (good, 1.17 h)	71.1° 07:05	6.66	94%	73.9°
2043-04-27 Mon	33	—	unknown	03:30–04:40 (good, 1.17 h)	71.1° 07:00	6.6	88%	66.4°
2043-04-28 Tue	34	—	unknown	03:10–04:35 (good, 1.42 h)	71.1° 06:55	6.54	82%	59.5°
2043-04-29 Wed	37	—	unknown	02:20–04:35 (good, 2.25 h)	71.1° 06:50	6.49	74%	53.6°
2043-04-30 Thu	50	—	unknown	01:45–04:35 (good, 2.83 h)	71.1° 06:50	6.43	64%	49.2°
2043-05-01 Fri	57	—	unknown	01:40–04:30 (good, 2.83 h)	71.1° 06:45	6.37	55%	46.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-04-02&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.