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: 05-03 (76), 05-02 (75), 05-05 (75), 04-30 (74), 05-01 (74) — by astronomy; check the weather when the night is within four days.

2047-04-13astronomy score per night — click a bar for that night2047-05-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2047-04-30 Tue	74	—	unknown	01:45–04:35 (good, 2.83 h)	71.1° 06:50	6.43	28%	132.0°
2047-05-01 Wed	74	—	unknown	01:45–04:30 (good, 2.75 h)	71.1° 06:45	6.37	37%	137.2°
2047-05-02 Thu	75	—	unknown	01:40–04:30 (good, 2.83 h)	71.2° 06:40	6.31	48%	139.7°
2047-05-03 Fri	76	—	unknown	01:40–04:30 (good, 2.83 h)	71.2° 06:35	6.25	58%	138.7°
2047-05-04 Sat	74	—	unknown	01:35–04:25 (good, 2.83 h)	71.1° 06:30	6.19	69%	134.1°
2047-05-05 Sun	75	—	unknown	01:35–04:25 (good, 2.83 h)	71.1° 06:30	6.14	79%	126.7°
2047-05-06 Mon	73	—	unknown	01:35–04:20 (good, 2.75 h)	71.2° 06:25	6.08	88%	117.2°
2047-05-07 Tue	61	—	unknown	01:35–04:20 (good, 2.75 h)	71.2° 06:20	6.02	95%	106.5°
2047-05-08 Wed	52	—	unknown	01:40–04:20 (good, 2.67 h)	71.1° 06:15	5.97	99%	95.0°
2047-05-09 Thu	44	—	unknown	02:20–04:15 (good, 1.92 h)	71.1° 06:10	5.91	100%	83.4°
2047-05-10 Fri	38	—	unknown	03:00–04:15 (good, 1.25 h)	71.1° 06:10	5.85	98%	72.1°
2047-05-11 Sat	35	—	unknown	03:30–04:15 (good, 0.75 h)	71.2° 06:05	5.8	93%	61.6°
2047-05-12 Sun	34	—	unknown	03:45–04:10 (good, 0.42 h)	71.2° 06:00	5.74	86%	52.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-04-13&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.