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: 04-29 (72), 04-27 (71), 04-28 (71), 04-25 (69), 04-26 (69) — by astronomy; check the weather when the night is within four days.

2047-03-31astronomy score per night — click a bar for that night2047-04-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-03-31 Sun	45	—	unknown	03:45–05:30 (good, 1.75 h)	71.2° 08:45	8.14	25%	110.5°
2047-04-01 Mon	46	—	unknown	03:40–05:30 (good, 1.83 h)	71.1° 08:40	8.09	33%	119.0°
2047-04-02 Tue	47	—	unknown	03:35–05:30 (good, 1.92 h)	71.1° 08:40	8.03	43%	126.8°
2047-04-03 Wed	48	—	unknown	03:35–05:25 (good, 1.83 h)	71.1° 08:35	7.98	53%	133.4°
2047-04-04 Thu	49	—	unknown	03:35–05:25 (good, 1.83 h)	71.2° 08:30	7.92	63%	138.0°
2047-04-05 Fri	48	—	unknown	03:30–05:20 (good, 1.83 h)	71.1° 08:25	7.87	74%	139.5°
2047-04-06 Sat	48	—	unknown	03:30–05:20 (good, 1.83 h)	71.1° 08:20	7.81	83%	137.2°
2047-04-07 Sun	45	—	unknown	03:25–05:20 (good, 1.92 h)	71.1° 08:20	7.75	91%	131.3°
2047-04-08 Mon	43	—	unknown	03:25–05:15 (good, 1.83 h)	71.2° 08:15	7.7	96%	122.7°
2047-04-09 Tue	40	—	unknown	03:25–05:15 (good, 1.83 h)	71.2° 08:10	7.64	99%	112.5°
2047-04-10 Wed	35	—	unknown	03:25–05:10 (good, 1.75 h)	71.1° 08:05	7.58	99%	101.2°
2047-04-11 Thu	31	—	unknown	03:35–05:10 (good, 1.58 h)	71.1° 08:00	7.53	96%	89.7°
2047-04-12 Fri	29	—	unknown	04:00–05:10 (good, 1.17 h)	71.1° 08:00	7.47	91%	78.3°
2047-04-13 Sat	28	—	unknown	04:05–05:05 (good, 1.0 h)	71.2° 07:55	7.41	83%	67.6°
2047-04-14 Sun	29	—	unknown	03:45–05:05 (good, 1.33 h)	71.2° 07:50	7.36	73%	57.9°
2047-04-15 Mon	31	—	unknown	03:10–05:00 (good, 1.83 h)	71.1° 07:45	7.3	63%	49.7°
2047-04-16 Tue	37	—	unknown	03:00–05:00 (good, 2.0 h)	71.1° 07:45	7.24	52%	43.8°
2047-04-17 Wed	47	—	unknown	02:40–05:00 (good, 2.33 h)	71.1° 07:40	7.18	42%	40.7°
2047-04-18 Thu	53	—	unknown	02:35–04:55 (good, 2.33 h)	71.2° 07:35	7.12	32%	40.9°
2047-04-19 Fri	58	—	unknown	02:30–04:55 (good, 2.42 h)	71.2° 07:30	7.07	23%	44.0°
2047-04-20 Sat	61	—	unknown	02:25–04:50 (good, 2.42 h)	71.1° 07:25	7.01	16%	49.4°
2047-04-21 Sun	64	—	unknown	02:20–04:50 (good, 2.5 h)	71.1° 07:25	6.95	10%	56.4°
2047-04-22 Mon	65	—	unknown	02:20–04:50 (good, 2.5 h)	71.2° 07:20	6.89	5%	64.3°
2047-04-23 Tue	66	—	unknown	02:15–04:45 (good, 2.5 h)	71.2° 07:15	6.83	2%	72.7°
2047-04-24 Wed	67	—	unknown	02:10–04:45 (good, 2.58 h)	71.1° 07:10	6.78	0%	81.6°
2047-04-25 Thu	69	—	unknown	02:05–04:45 (good, 2.67 h)	71.1° 07:05	6.72	1%	90.6°
2047-04-26 Fri	69	—	unknown	02:00–04:40 (good, 2.67 h)	71.1° 07:05	6.66	3%	99.6°
2047-04-27 Sat	71	—	unknown	02:00–04:40 (good, 2.67 h)	71.2° 07:00	6.6	7%	108.5°
2047-04-28 Sun	71	—	unknown	01:55–04:35 (good, 2.67 h)	71.2° 06:55	6.54	12%	117.1°
2047-04-29 Mon	72	—	unknown	01:50–04:35 (good, 2.75 h)	71.1° 06:50	6.48	19%	125.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-03-31&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.