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: 03-26 (41), 03-24 (40), 03-25 (40), 03-22 (39), 03-23 (39) — by astronomy; check the weather when the night is within four days.

2045-02-25astronomy score per night — click a bar for that night2045-03-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-02-25 Sat	19	—	unknown	04:55–05:30 (good, 0.58 h)	71.1° 09:55	9.81	64%	117.8°
2045-02-26 Sun	20	—	unknown	04:50–05:30 (good, 0.67 h)	71.1° 09:55	9.76	74%	125.9°
2045-02-27 Mon	19	—	unknown	04:55–05:25 (good, 0.5 h)	71.1° 09:50	9.72	84%	132.3°
2045-02-28 Tue	18	—	unknown	04:50–05:25 (good, 0.58 h)	71.1° 09:45	9.67	92%	135.7°
2045-03-01 Wed	18	—	unknown	04:50–05:25 (good, 0.58 h)	71.1° 09:40	9.63	97%	135.2°
2045-03-02 Thu	18	—	unknown	04:45–05:25 (good, 0.67 h)	71.1° 09:40	9.58	100%	131.0°
2045-03-03 Fri	19	—	unknown	04:45–05:20 (good, 0.58 h)	71.1° 09:35	9.54	99%	124.1°
2045-03-04 Sat	18	—	unknown	04:40–05:20 (good, 0.67 h)	71.1° 09:30	9.49	96%	115.4°
2045-03-05 Sun	18	—	unknown	04:40–05:20 (good, 0.67 h)	71.1° 09:25	9.44	91%	106.0°
2045-03-06 Mon	16	—	unknown	04:40–05:15 (good, 0.58 h)	71.1° 09:20	9.4	84%	96.3°
2045-03-07 Tue	17	—	unknown	04:40–05:15 (good, 0.58 h)	71.1° 09:20	9.35	75%	86.9°
2045-03-08 Wed	17	—	unknown	04:35–05:15 (good, 0.67 h)	71.1° 09:15	9.3	66%	77.7°
2045-03-09 Thu	18	—	unknown	04:25–05:10 (good, 0.75 h)	71.1° 09:10	9.25	56%	69.2°
2045-03-10 Fri	20	—	unknown	04:20–05:10 (good, 0.83 h)	71.1° 09:05	9.2	46%	61.4°
2045-03-11 Sat	22	—	unknown	04:10–05:10 (good, 1.0 h)	71.1° 09:00	9.16	37%	54.6°
2045-03-12 Sun	25	—	unknown	03:55–05:05 (good, 1.17 h)	71.1° 09:00	9.11	28%	49.1°
2045-03-13 Mon	30	—	unknown	03:55–05:05 (good, 1.17 h)	71.1° 08:55	9.06	20%	45.4°
2045-03-14 Tue	31	—	unknown	03:50–05:00 (good, 1.17 h)	71.1° 08:50	9.01	13%	44.0°
2045-03-15 Wed	32	—	unknown	03:45–05:00 (good, 1.25 h)	71.1° 08:45	8.96	7%	45.1°
2045-03-16 Thu	33	—	unknown	03:40–05:00 (good, 1.33 h)	71.1° 08:45	8.91	3%	48.7°
2045-03-17 Fri	34	—	unknown	03:35–04:55 (good, 1.33 h)	71.1° 08:40	8.86	1%	54.2°
2045-03-18 Sat	35	—	unknown	03:35–04:55 (good, 1.33 h)	71.1° 08:35	8.8	0%	61.2°
2045-03-19 Sun	36	—	unknown	03:30–04:55 (good, 1.42 h)	71.1° 08:30	8.75	2%	69.4°
2045-03-20 Mon	36	—	unknown	03:25–04:50 (good, 1.42 h)	71.1° 08:25	8.7	5%	78.2°
2045-03-21 Tue	38	—	unknown	03:20–04:50 (good, 1.5 h)	71.1° 08:25	8.65	11%	87.5°
2045-03-22 Wed	39	—	unknown	03:20–04:50 (good, 1.5 h)	71.1° 08:20	8.6	18%	97.1°
2045-03-23 Thu	39	—	unknown	03:15–04:45 (good, 1.5 h)	71.1° 08:15	8.54	27%	106.5°
2045-03-24 Fri	40	—	unknown	03:10–04:45 (good, 1.58 h)	71.1° 08:10	8.49	38%	115.7°
2045-03-25 Sat	40	—	unknown	04:05–05:40 (good, 1.58 h)	71.1° 09:05	8.44	49%	123.9°
2045-03-26 Sun	41	—	unknown	04:05–05:40 (good, 1.58 h)	71.1° 09:05	8.39	60%	130.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-02-25&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.