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 Vega: 04-20 (100), 04-21 (100), 04-22 (100), 04-23 (100), 04-24 (100) — by astronomy; check the weather when the night is within four days.

2044-04-10astronomy score per night — click a bar for that night2044-05-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-04-10 Sun	71	—	unknown	01:30–05:10 (good, 3.67 h)	87.1° 06:40	7.54	98%	96.3°
2044-04-11 Mon	67	—	unknown	01:55–05:10 (good, 3.25 h)	87.1° 06:35	7.49	100%	91.2°
2044-04-12 Tue	62	—	unknown	02:05–05:05 (good, 3.0 h)	87.1° 06:30	7.43	100%	86.2°
2044-04-13 Wed	60	—	unknown	02:05–05:05 (good, 3.0 h)	87.1° 06:30	7.37	98%	81.3°
2044-04-14 Thu	60	—	unknown	01:45–05:05 (good, 3.33 h)	87.1° 06:25	7.31	94%	76.9°
2044-04-15 Fri	61	—	unknown	01:00–05:00 (good, 4.0 h)	87.1° 06:20	7.26	88%	73.1°
2044-04-16 Sat	72	—	unknown	00:20–05:00 (good, 4.67 h)	87.1° 06:15	7.2	81%	70.0°
2044-04-17 Sun	86	—	unknown	00:20–04:55 (good, 4.58 h)	87.1° 06:10	7.14	73%	67.8°
2044-04-18 Mon	92	—	unknown	00:15–04:55 (good, 4.67 h)	87.1° 06:10	7.08	65%	66.5°
2044-04-19 Tue	97	—	unknown	00:10–04:55 (good, 4.75 h)	87.1° 06:05	7.02	55%	66.3°
2044-04-20 Wed	100	—	unknown	00:05–04:50 (good, 4.75 h)	87.1° 06:00	6.97	46%	67.2°
2044-04-21 Thu	100	—	unknown	00:00–04:50 (good, 4.83 h)	87.1° 05:55	6.91	36%	69.2°
2044-04-22 Fri	100	—	unknown	00:00–04:45 (good, 4.75 h)	87.1° 05:50	6.85	27%	72.2°
2044-04-23 Sat	100	—	unknown	23:55–04:45 (good, 4.83 h)	87.1° 05:50	6.79	18%	76.2°
2044-04-24 Sun	100	—	unknown	23:50–04:45 (good, 4.92 h)	87.1° 05:45	6.73	11%	81.0°
2044-04-25 Mon	100	—	unknown	23:45–04:40 (good, 4.92 h)	87.1° 05:40	6.67	5%	86.3°
2044-04-26 Tue	100	—	unknown	23:40–04:40 (good, 5.0 h)	87.1° 05:35	6.62	1%	92.0°
2044-04-27 Wed	100	—	unknown	23:40–04:40 (good, 5.0 h)	87.1° 05:35	6.56	0%	97.7°
2044-04-28 Thu	100	—	unknown	23:35–04:35 (good, 5.0 h)	87.1° 05:30	6.5	2%	103.1°
2044-04-29 Fri	100	—	unknown	23:30–04:35 (good, 5.08 h)	87.1° 05:25	6.44	6%	107.8°
2044-04-30 Sat	100	—	unknown	23:30–04:30 (good, 5.0 h)	87.1° 05:20	6.38	14%	111.2°
2044-05-01 Sun	100	—	unknown	23:25–04:30 (good, 5.08 h)	87.1° 05:15	6.33	23%	113.3°
2044-05-02 Mon	100	—	unknown	23:25–04:30 (good, 5.08 h)	87.1° 05:15	6.27	33%	113.8°
2044-05-03 Tue	100	—	unknown	23:20–04:25 (good, 5.08 h)	87.1° 05:10	6.21	44%	112.7°
2044-05-04 Wed	100	—	unknown	23:20–04:25 (good, 5.08 h)	87.1° 05:05	6.15	56%	110.3°
2044-05-05 Thu	100	—	unknown	23:20–04:25 (good, 5.08 h)	87.1° 05:00	6.1	66%	106.8°
2044-05-06 Fri	100	—	unknown	23:25–04:20 (good, 4.92 h)	87.1° 04:55	6.04	76%	102.5°
2044-05-07 Sat	100	—	unknown	23:25–04:20 (good, 4.92 h)	87.1° 04:55	5.98	84%	97.7°
2044-05-08 Sun	83	—	unknown	23:40–04:20 (good, 4.67 h)	87.1° 04:50	5.93	91%	92.6°
2044-05-09 Mon	79	—	unknown	00:05–04:15 (good, 4.17 h)	87.1° 04:45	5.87	96%	87.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-04-10&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.