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: 02-14 (59), 02-15 (59), 02-16 (59), 02-13 (58), 02-12 (57) — by astronomy; check the weather when the night is within four days.

2027-01-20astronomy score per night — click a bar for that night2027-02-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-01-20 Wed	24	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 10:55	11.11	96%	114.5°
2027-01-21 Thu	23	—	unknown	05:15–06:05 (good, 0.83 h)	87.1° 10:55	11.09	100%	115.6°
2027-01-22 Fri	23	—	unknown	05:10–06:05 (good, 0.92 h)	87.1° 10:50	11.06	100%	114.7°
2027-01-23 Sat	23	—	unknown	05:10–06:05 (good, 0.92 h)	87.1° 10:45	11.04	97%	112.1°
2027-01-24 Sun	23	—	unknown	05:10–06:05 (good, 0.92 h)	87.1° 10:40	11.01	92%	108.0°
2027-01-25 Mon	23	—	unknown	05:05–06:05 (good, 1.0 h)	87.1° 10:35	10.98	84%	103.0°
2027-01-26 Tue	24	—	unknown	05:00–06:05 (good, 1.08 h)	87.1° 10:35	10.95	75%	97.5°
2027-01-27 Wed	25	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:30	10.92	65%	91.9°
2027-01-28 Thu	27	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:25	10.89	55%	86.3°
2027-01-29 Fri	30	—	unknown	04:40–06:00 (good, 1.33 h)	87.1° 10:20	10.86	45%	81.1°
2027-01-30 Sat	33	—	unknown	04:35–06:00 (good, 1.42 h)	87.1° 10:20	10.83	36%	76.3°
2027-01-31 Sun	36	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:15	10.8	27%	72.1°
2027-02-01 Mon	40	—	unknown	04:15–06:00 (good, 1.75 h)	87.1° 10:10	10.77	19%	68.7°
2027-02-02 Tue	44	—	unknown	04:10–06:00 (good, 1.83 h)	87.1° 10:05	10.73	12%	66.2°
2027-02-03 Wed	47	—	unknown	04:10–06:00 (good, 1.83 h)	87.1° 10:00	10.7	7%	64.8°
2027-02-04 Thu	47	—	unknown	04:05–05:55 (good, 1.83 h)	87.1° 10:00	10.66	3%	64.5°
2027-02-05 Fri	48	—	unknown	04:00–05:55 (good, 1.92 h)	87.1° 09:55	10.63	0%	65.3°
2027-02-06 Sat	50	—	unknown	03:55–05:55 (good, 2.0 h)	87.1° 09:50	10.59	0%	67.3°
2027-02-07 Sun	51	—	unknown	03:50–05:55 (good, 2.08 h)	87.1° 09:45	10.56	2%	70.3°
2027-02-08 Mon	53	—	unknown	03:50–05:55 (good, 2.08 h)	87.1° 09:40	10.52	5%	74.3°
2027-02-09 Tue	53	—	unknown	03:45–05:50 (good, 2.08 h)	87.1° 09:40	10.49	10%	78.9°
2027-02-10 Wed	54	—	unknown	03:40–05:50 (good, 2.17 h)	87.1° 09:35	10.45	17%	84.1°
2027-02-11 Thu	55	—	unknown	03:35–05:50 (good, 2.25 h)	87.1° 09:30	10.41	25%	89.6°
2027-02-12 Fri	57	—	unknown	03:30–05:50 (good, 2.33 h)	87.1° 09:25	10.37	35%	95.3°
2027-02-13 Sat	58	—	unknown	03:30–05:45 (good, 2.25 h)	87.1° 09:25	10.33	46%	100.8°
2027-02-14 Sun	59	—	unknown	03:25–05:45 (good, 2.33 h)	87.1° 09:20	10.3	57%	105.9°
2027-02-15 Mon	59	—	unknown	03:30–05:45 (good, 2.25 h)	87.1° 09:15	10.26	68%	110.3°
2027-02-16 Tue	59	—	unknown	03:25–05:45 (good, 2.33 h)	87.1° 09:10	10.22	78%	113.6°
2027-02-17 Wed	57	—	unknown	03:25–05:40 (good, 2.25 h)	87.1° 09:05	10.18	87%	115.4°
2027-02-18 Thu	51	—	unknown	03:25–05:40 (good, 2.25 h)	87.1° 09:05	10.13	94%	115.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-01-20&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.