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 North America Nebula: 03-17 (33), 03-16 (30), 03-02 (29), 03-04 (29), 03-05 (29) — by astronomy; check the weather when the night is within four days.

2031-02-16astronomy score per night — click a bar for that night2031-03-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-02-16 Sun	14	—	unknown	05:25–05:45 (good, 0.33 h)	87.2° 11:30	10.21	28%	80.7°
2031-02-17 Mon	15	—	unknown	05:20–05:40 (good, 0.33 h)	87.2° 11:30	10.17	18%	72.3°
2031-02-18 Tue	17	—	unknown	05:10–05:40 (good, 0.5 h)	87.2° 11:25	10.13	10%	64.7°
2031-02-19 Wed	19	—	unknown	05:05–05:40 (good, 0.58 h)	87.2° 11:20	10.09	4%	58.5°
2031-02-20 Thu	21	—	unknown	05:00–05:40 (good, 0.67 h)	87.2° 11:15	10.05	1%	54.3°
2031-02-21 Fri	20	—	unknown	05:00–05:35 (good, 0.58 h)	87.2° 11:15	10.01	0%	52.6°
2031-02-22 Sat	22	—	unknown	04:55–05:35 (good, 0.67 h)	87.2° 11:10	9.96	2%	53.5°
2031-02-23 Sun	23	—	unknown	04:50–05:35 (good, 0.75 h)	87.2° 11:05	9.92	7%	56.8°
2031-02-24 Mon	24	—	unknown	04:45–05:35 (good, 0.83 h)	87.2° 11:00	9.88	13%	61.9°
2031-02-25 Tue	24	—	unknown	04:40–05:30 (good, 0.83 h)	87.2° 10:55	9.83	20%	68.1°
2031-02-26 Wed	25	—	unknown	04:40–05:30 (good, 0.83 h)	87.2° 10:55	9.79	29%	75.0°
2031-02-27 Thu	26	—	unknown	04:35–05:30 (good, 0.92 h)	87.2° 10:50	9.75	38%	82.2°
2031-02-28 Fri	26	—	unknown	04:30–05:25 (good, 0.92 h)	87.2° 10:45	9.7	48%	89.4°
2031-03-01 Sat	27	—	unknown	04:25–05:25 (good, 1.0 h)	87.2° 10:40	9.66	57%	96.7°
2031-03-02 Sun	29	—	unknown	04:20–05:25 (good, 1.08 h)	87.2° 10:35	9.61	66%	103.7°
2031-03-03 Mon	28	—	unknown	04:20–05:20 (good, 1.0 h)	87.2° 10:35	9.56	75%	110.3°
2031-03-04 Tue	29	—	unknown	04:20–05:20 (good, 1.0 h)	87.2° 10:30	9.52	83%	116.3°
2031-03-05 Wed	29	—	unknown	04:20–05:20 (good, 1.0 h)	87.2° 10:25	9.47	89%	121.4°
2031-03-06 Thu	26	—	unknown	04:15–05:15 (good, 1.0 h)	87.2° 10:20	9.42	95%	125.2°
2031-03-07 Fri	27	—	unknown	04:15–05:15 (good, 1.0 h)	87.2° 10:20	9.38	98%	127.2°
2031-03-08 Sat	26	—	unknown	04:10–05:15 (good, 1.08 h)	87.2° 10:15	9.33	100%	127.2°
2031-03-09 Sun	26	—	unknown	04:10–05:10 (good, 1.0 h)	87.2° 10:10	9.28	99%	124.9°
2031-03-10 Mon	27	—	unknown	04:05–05:10 (good, 1.08 h)	87.2° 10:05	9.23	96%	120.6°
2031-03-11 Tue	27	—	unknown	04:05–05:10 (good, 1.08 h)	87.2° 10:00	9.18	91%	114.7°
2031-03-12 Wed	25	—	unknown	04:00–05:05 (good, 1.08 h)	87.2° 10:00	9.14	84%	107.5°
2031-03-13 Thu	25	—	unknown	04:00–05:05 (good, 1.08 h)	87.2° 09:55	9.09	75%	99.5°
2031-03-14 Fri	26	—	unknown	03:55–05:05 (good, 1.17 h)	87.2° 09:50	9.04	65%	91.0°
2031-03-15 Sat	27	—	unknown	03:50–05:00 (good, 1.17 h)	87.2° 09:45	8.99	54%	82.5°
2031-03-16 Sun	30	—	unknown	03:40–05:00 (good, 1.33 h)	87.2° 09:40	8.94	42%	74.2°
2031-03-17 Mon	33	—	unknown	03:35–05:00 (good, 1.42 h)	87.2° 09:40	8.89	31%	66.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-02-16&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.