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: 04-27 (100), 04-28 (100), 04-29 (100), 04-30 (100), 05-01 (100) — by astronomy; check the weather when the night is within four days.

2038-04-27astronomy score per night — click a bar for that night2038-05-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-04-27 Tue	100	—	unknown	23:40–04:40 (good, 5.0 h)	87.1° 05:35	6.59	34%	72.6°
2038-04-28 Wed	100	—	unknown	23:35–04:35 (good, 5.0 h)	87.1° 05:30	6.53	25%	77.6°
2038-04-29 Thu	100	—	unknown	23:30–04:35 (good, 5.08 h)	87.1° 05:25	6.47	17%	83.0°
2038-04-30 Fri	100	—	unknown	23:30–04:35 (good, 5.08 h)	87.1° 05:25	6.42	11%	88.6°
2038-05-01 Sat	100	—	unknown	23:25–04:30 (good, 5.08 h)	87.1° 05:20	6.36	6%	94.2°
2038-05-02 Sun	100	—	unknown	23:20–04:30 (good, 5.17 h)	87.1° 05:15	6.3	2%	99.7°
2038-05-03 Mon	100	—	unknown	23:15–04:25 (good, 5.17 h)	87.1° 05:10	6.24	0%	104.8°
2038-05-04 Tue	100	—	unknown	23:15–04:25 (good, 5.17 h)	87.1° 05:05	6.19	0%	109.4°
2038-05-05 Wed	100	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:05	6.13	2%	113.3°
2038-05-06 Thu	100	—	unknown	23:05–04:20 (good, 5.25 h)	87.1° 05:00	6.07	6%	116.3°
2038-05-07 Fri	100	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:55	6.01	11%	118.0°
2038-05-08 Sat	100	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:50	5.96	18%	118.3°
2038-05-09 Sun	100	—	unknown	22:55–04:15 (good, 5.33 h)	87.1° 04:45	5.9	27%	117.1°
2038-05-10 Mon	100	—	unknown	22:55–04:15 (good, 5.33 h)	87.1° 04:45	5.85	37%	114.5°
2038-05-11 Tue	100	—	unknown	22:55–04:15 (good, 5.33 h)	87.1° 04:40	5.79	47%	110.5°
2038-05-12 Wed	100	—	unknown	22:55–04:10 (good, 5.25 h)	87.1° 04:35	5.73	58%	105.3°
2038-05-13 Thu	100	—	unknown	23:00–04:10 (good, 5.17 h)	87.1° 04:30	5.68	69%	99.3°
2038-05-14 Fri	85	—	unknown	23:05–04:10 (good, 5.08 h)	87.1° 04:30	5.63	79%	92.5°
2038-05-15 Sat	80	—	unknown	23:55–04:05 (good, 4.17 h)	87.1° 04:25	5.57	88%	85.6°
2038-05-16 Sun	72	—	unknown	00:40–04:05 (good, 3.42 h)	87.1° 04:20	5.52	95%	78.7°
2038-05-17 Mon	63	—	unknown	01:20–04:05 (good, 2.75 h)	87.1° 04:15	5.47	99%	72.5°
2038-05-18 Tue	57	—	unknown	02:10–04:00 (good, 1.83 h)	87.1° 04:10	5.42	100%	67.3°
2038-05-19 Wed	55	—	unknown	01:20–04:00 (good, 2.67 h)	87.1° 04:10	5.37	98%	63.7°
2038-05-20 Thu	80	—	unknown	23:10–04:00 (good, 4.83 h)	87.1° 04:05	5.32	94%	61.9°
2038-05-21 Fri	89	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.27	87%	62.0°
2038-05-22 Sat	96	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.22	78%	63.9°
2038-05-23 Sun	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.17	69%	67.1°
2038-05-24 Mon	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.12	59%	71.3°
2038-05-25 Tue	100	—	unknown	22:50–03:55 (good, 5.08 h)	87.1° 03:45	5.08	49%	76.3°
2038-05-26 Wed	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.03	40%	81.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-04-27&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.