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: 01-18 (23), 01-17 (20), 01-16 (19), 12-20 (18), 01-15 (17) — by astronomy; check the weather when the night is within four days.

2030-12-20astronomy score per night — click a bar for that night2031-01-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-12-20 Fri	18	—	unknown	18:35–19:00 (good, 0.42 h)	87.1° 13:05	11.51	20%	82.7°
2030-12-21 Sat	16	—	unknown	18:35–19:00 (good, 0.42 h)	87.1° 13:00	11.51	11%	75.4°
2030-12-22 Sun	15	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 12:55	11.51	5%	68.8°
2030-12-23 Mon	13	—	unknown	18:40–18:50 (good, 0.17 h)	87.1° 12:50	11.51	1%	63.3°
2030-12-24 Tue	12	—	unknown	18:40–18:45 (good, 0.08 h)	87.1° 12:45	11.5	0%	59.6°
2030-12-25 Wed	11	—	unknown	18:05–19:15 (marginal, 1.17 h)	87.1° 12:45	11.5	2%	58.3°
2030-12-26 Thu	10	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:40	11.5	7%	59.3°
2030-12-27 Fri	9	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	14%	62.5°
2030-12-28 Sat	8	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	23%	67.3°
2030-12-29 Sun	8	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:25	11.48	33%	73.1°
2030-12-30 Mon	8	—	unknown	05:55–06:10 (marginal, 0.25 h)	87.1° 12:25	11.47	44%	79.4°
2030-12-31 Tue	8	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	54%	86.0°
2031-01-01 Wed	9	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	64%	92.5°
2031-01-02 Thu	10	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.44	72%	98.8°
2031-01-03 Fri	10	—	unknown	05:40–06:45 (marginal, 1.08 h)	87.1° 12:10	11.43	81%	104.8°
2031-01-04 Sat	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 12:00	11.42	88%	110.1°
2031-01-05 Sun	12	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 12:00	11.4	93%	114.7°
2031-01-06 Mon	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 11:50	11.39	97%	118.4°
2031-01-07 Tue	12	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 11:50	11.38	99%	120.8°
2031-01-08 Wed	12	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:45	11.36	100%	121.7°
2031-01-09 Thu	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:40	11.34	99%	121.1°
2031-01-10 Fri	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:35	11.33	96%	119.0°
2031-01-11 Sat	15	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:30	11.31	91%	115.5°
2031-01-12 Sun	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:30	11.29	84%	110.9°
2031-01-13 Mon	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:25	11.27	76%	105.2°
2031-01-14 Tue	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:20	11.25	67%	98.9°
2031-01-15 Wed	17	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:15	11.23	56%	92.0°
2031-01-16 Thu	19	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:15	11.21	46%	84.9°
2031-01-17 Fri	20	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:10	11.19	35%	77.8°
2031-01-18 Sat	23	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:05	11.16	24%	71.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-12-20&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.