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: 04-12 (57), 04-14 (57), 04-15 (57), 04-17 (57), 04-13 (56) — by astronomy; check the weather when the night is within four days.

2046-03-21astronomy score per night — click a bar for that night2046-04-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-03-21 Wed	30	—	unknown	03:35–04:50 (good, 1.25 h)	71.1° 08:25	8.66	100%	123.5°
2046-03-22 Thu	29	—	unknown	03:35–04:50 (good, 1.25 h)	71.1° 08:20	8.61	99%	113.8°
2046-03-23 Fri	25	—	unknown	03:35–04:45 (good, 1.17 h)	71.1° 08:15	8.56	96%	103.3°
2046-03-24 Sat	24	—	unknown	04:35–05:45 (good, 1.17 h)	71.1° 09:10	8.5	90%	92.5°
2046-03-25 Sun	23	—	unknown	04:35–05:45 (good, 1.17 h)	71.1° 09:10	8.45	83%	82.0°
2046-03-26 Mon	23	—	unknown	04:30–05:40 (good, 1.17 h)	71.1° 09:05	8.4	74%	72.1°
2046-03-27 Tue	25	—	unknown	04:25–05:40 (good, 1.25 h)	71.1° 09:00	8.35	64%	63.0°
2046-03-28 Wed	27	—	unknown	04:15–05:35 (good, 1.33 h)	71.1° 08:55	8.29	54%	55.0°
2046-03-29 Thu	31	—	unknown	04:05–05:35 (good, 1.5 h)	71.1° 08:55	8.24	44%	48.6°
2046-03-30 Fri	37	—	unknown	03:45–05:35 (good, 1.83 h)	71.1° 08:50	8.18	34%	44.2°
2046-03-31 Sat	41	—	unknown	03:45–05:30 (good, 1.75 h)	71.1° 08:45	8.13	25%	42.3°
2046-04-01 Sun	45	—	unknown	03:40–05:30 (good, 1.83 h)	71.1° 08:40	8.07	18%	43.1°
2046-04-02 Mon	46	—	unknown	03:35–05:25 (good, 1.83 h)	71.1° 08:35	8.02	11%	46.4°
2046-04-03 Tue	48	—	unknown	03:30–05:25 (good, 1.92 h)	71.1° 08:35	7.96	6%	51.7°
2046-04-04 Wed	50	—	unknown	03:30–05:25 (good, 1.92 h)	71.1° 08:30	7.91	2%	58.4°
2046-04-05 Thu	50	—	unknown	03:25–05:20 (good, 1.92 h)	71.1° 08:25	7.85	0%	66.1°
2046-04-06 Fri	51	—	unknown	03:20–05:20 (good, 2.0 h)	71.1° 08:20	7.8	0%	74.5°
2046-04-07 Sat	51	—	unknown	03:15–05:15 (good, 2.0 h)	71.1° 08:15	7.74	2%	83.4°
2046-04-08 Sun	52	—	unknown	03:10–05:15 (good, 2.08 h)	71.1° 08:15	7.68	6%	92.5°
2046-04-09 Mon	54	—	unknown	03:10–05:15 (good, 2.08 h)	71.1° 08:10	7.63	11%	101.7°
2046-04-10 Tue	54	—	unknown	03:05–05:10 (good, 2.08 h)	71.1° 08:05	7.57	18%	110.7°
2046-04-11 Wed	55	—	unknown	03:00–05:10 (good, 2.17 h)	71.1° 08:00	7.51	27%	119.4°
2046-04-12 Thu	57	—	unknown	02:55–05:10 (good, 2.25 h)	71.1° 08:00	7.46	37%	127.2°
2046-04-13 Fri	56	—	unknown	02:55–05:05 (good, 2.17 h)	71.1° 07:55	7.4	48%	133.5°
2046-04-14 Sat	57	—	unknown	02:55–05:05 (good, 2.17 h)	71.1° 07:50	7.34	59%	137.3°
2046-04-15 Sun	57	—	unknown	02:50–05:00 (good, 2.17 h)	71.1° 07:45	7.28	70%	137.5°
2046-04-16 Mon	56	—	unknown	02:50–05:00 (good, 2.17 h)	71.1° 07:40	7.23	80%	134.0°
2046-04-17 Tue	57	—	unknown	02:45–05:00 (good, 2.25 h)	71.1° 07:40	7.17	88%	127.3°
2046-04-18 Wed	51	—	unknown	02:45–04:55 (good, 2.17 h)	71.1° 07:35	7.11	95%	118.3°
2046-04-19 Thu	45	—	unknown	02:45–04:55 (good, 2.17 h)	71.1° 07:30	7.05	99%	108.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-03-21&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.