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: 02-12 (57), 02-14 (57), 02-11 (56), 02-13 (56), 02-10 (55) — by astronomy; check the weather when the night is within four days.

2030-01-20astronomy score per night — click a bar for that night2030-02-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-01-20 Sun	23	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 10:55	11.11	98%	117.8°
2030-01-21 Mon	22	—	unknown	05:15–06:05 (good, 0.83 h)	87.1° 10:50	11.08	94%	114.1°
2030-01-22 Tue	22	—	unknown	05:15–06:05 (good, 0.83 h)	87.1° 10:50	11.05	88%	109.1°
2030-01-23 Wed	22	—	unknown	05:10–06:05 (good, 0.92 h)	87.1° 10:45	11.03	80%	103.0°
2030-01-24 Thu	23	—	unknown	05:05–06:05 (good, 1.0 h)	87.1° 10:40	11.0	70%	96.3°
2030-01-25 Fri	25	—	unknown	05:00–06:05 (good, 1.08 h)	87.1° 10:35	10.97	59%	89.3°
2030-01-26 Sat	27	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:30	10.94	48%	82.2°
2030-01-27 Sun	30	—	unknown	04:45–06:05 (good, 1.33 h)	87.1° 10:30	10.91	37%	75.5°
2030-01-28 Mon	33	—	unknown	04:40–06:05 (good, 1.42 h)	87.1° 10:25	10.88	26%	69.4°
2030-01-29 Tue	37	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:20	10.85	17%	64.5°
2030-01-30 Wed	41	—	unknown	04:20–06:00 (good, 1.67 h)	87.1° 10:15	10.82	9%	61.1°
2030-01-31 Thu	43	—	unknown	04:20–06:00 (good, 1.67 h)	87.1° 10:15	10.79	4%	59.6°
2030-02-01 Fri	43	—	unknown	04:15–06:00 (good, 1.75 h)	87.1° 10:10	10.76	1%	60.1°
2030-02-02 Sat	45	—	unknown	04:10–06:00 (good, 1.83 h)	87.1° 10:05	10.72	0%	62.4°
2030-02-03 Sun	47	—	unknown	04:05–06:00 (good, 1.92 h)	87.1° 10:00	10.69	2%	66.3°
2030-02-04 Mon	47	—	unknown	04:05–05:55 (good, 1.83 h)	87.1° 09:55	10.65	6%	71.2°
2030-02-05 Tue	49	—	unknown	04:00–05:55 (good, 1.92 h)	87.1° 09:55	10.62	12%	76.8°
2030-02-06 Wed	49	—	unknown	03:55–05:55 (good, 2.0 h)	87.1° 09:50	10.58	19%	82.8°
2030-02-07 Thu	51	—	unknown	03:50–05:55 (good, 2.08 h)	87.1° 09:45	10.55	27%	88.9°
2030-02-08 Fri	53	—	unknown	03:45–05:55 (good, 2.17 h)	87.1° 09:40	10.51	36%	94.9°
2030-02-09 Sat	53	—	unknown	03:45–05:50 (good, 2.08 h)	87.1° 09:35	10.48	45%	100.8°
2030-02-10 Sun	55	—	unknown	03:40–05:50 (good, 2.17 h)	87.1° 09:35	10.44	54%	106.3°
2030-02-11 Mon	56	—	unknown	03:35–05:50 (good, 2.25 h)	87.1° 09:30	10.4	64%	111.2°
2030-02-12 Tue	57	—	unknown	03:40–05:50 (good, 2.17 h)	87.1° 09:25	10.36	72%	115.3°
2030-02-13 Wed	56	—	unknown	03:35–05:45 (good, 2.17 h)	87.1° 09:20	10.32	81%	118.4°
2030-02-14 Thu	57	—	unknown	03:35–05:45 (good, 2.17 h)	87.1° 09:20	10.28	88%	120.2°
2030-02-15 Fri	51	—	unknown	03:30–05:45 (good, 2.25 h)	87.1° 09:15	10.24	94%	120.4°
2030-02-16 Sat	51	—	unknown	03:30–05:45 (good, 2.25 h)	87.1° 09:10	10.2	98%	118.8°
2030-02-17 Sun	48	—	unknown	03:30–05:40 (good, 2.17 h)	87.1° 09:05	10.16	100%	115.5°
2030-02-18 Mon	46	—	unknown	03:30–05:40 (good, 2.17 h)	87.1° 09:00	10.12	99%	110.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-01-20&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.