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: 04-12 (61), 04-09 (60), 04-10 (60), 04-11 (60), 04-13 (60) — by astronomy; check the weather when the night is within four days.

2030-03-18astronomy score per night — click a bar for that night2030-04-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-03-18 Mon	33	—	unknown	03:30–04:55 (good, 1.42 h)	87.2° 09:35	8.82	99%	127.1°
2030-03-19 Tue	33	—	unknown	03:30–04:55 (good, 1.42 h)	87.2° 09:30	8.77	100%	124.5°
2030-03-20 Wed	33	—	unknown	03:25–04:50 (good, 1.42 h)	87.2° 09:25	8.72	98%	119.5°
2030-03-21 Thu	32	—	unknown	03:25–04:50 (good, 1.42 h)	87.2° 09:20	8.67	93%	112.7°
2030-03-22 Fri	31	—	unknown	03:25–04:50 (good, 1.42 h)	87.2° 09:20	8.62	86%	104.7°
2030-03-23 Sat	30	—	unknown	03:20–04:45 (good, 1.42 h)	87.2° 09:15	8.56	77%	96.1°
2030-03-24 Sun	31	—	unknown	03:15–04:45 (good, 1.5 h)	87.2° 09:10	8.51	66%	87.3°
2030-03-25 Mon	33	—	unknown	03:10–04:45 (good, 1.58 h)	87.2° 09:05	8.46	55%	78.8°
2030-03-26 Tue	35	—	unknown	03:00–04:40 (good, 1.67 h)	87.2° 09:00	8.41	44%	71.0°
2030-03-27 Wed	39	—	unknown	02:45–04:40 (good, 1.92 h)	87.2° 09:00	8.35	34%	64.1°
2030-03-28 Thu	44	—	unknown	02:40–04:35 (good, 1.92 h)	87.2° 08:55	8.3	24%	58.5°
2030-03-29 Fri	48	—	unknown	02:35–04:35 (good, 2.0 h)	87.2° 08:50	8.24	16%	54.6°
2030-03-30 Sat	51	—	unknown	02:30–05:35 (good, 2.08 h)	87.2° 09:45	8.19	9%	52.7°
2030-03-31 Sun	52	—	unknown	03:25–05:30 (good, 2.08 h)	87.2° 09:40	8.14	4%	53.0°
2030-04-01 Mon	52	—	unknown	03:25–05:30 (good, 2.08 h)	87.2° 09:40	8.08	1%	55.2°
2030-04-02 Tue	52	—	unknown	03:20–05:25 (good, 2.08 h)	87.2° 09:35	8.03	0%	59.2°
2030-04-03 Wed	54	—	unknown	03:15–05:25 (good, 2.17 h)	87.2° 09:30	7.97	1%	64.5°
2030-04-04 Thu	56	—	unknown	03:10–05:25 (good, 2.25 h)	87.2° 09:25	7.91	4%	70.6°
2030-04-05 Fri	56	—	unknown	03:10–05:20 (good, 2.17 h)	87.2° 09:25	7.86	8%	77.3°
2030-04-06 Sat	57	—	unknown	03:05–05:20 (good, 2.25 h)	87.2° 09:20	7.8	14%	84.3°
2030-04-07 Sun	58	—	unknown	03:00–05:20 (good, 2.33 h)	87.2° 09:15	7.75	21%	91.5°
2030-04-08 Mon	58	—	unknown	02:55–05:15 (good, 2.33 h)	87.2° 09:10	7.69	29%	98.7°
2030-04-09 Tue	60	—	unknown	02:50–05:15 (good, 2.42 h)	87.2° 09:05	7.63	38%	105.7°
2030-04-10 Wed	60	—	unknown	02:50–05:10 (good, 2.33 h)	87.2° 09:05	7.58	48%	112.3°
2030-04-11 Thu	60	—	unknown	02:50–05:10 (good, 2.33 h)	87.2° 09:00	7.52	58%	118.3°
2030-04-12 Fri	61	—	unknown	02:45–05:10 (good, 2.42 h)	87.2° 08:55	7.46	68%	123.2°
2030-04-13 Sat	60	—	unknown	02:45–05:05 (good, 2.33 h)	87.2° 08:50	7.41	77%	126.5°
2030-04-14 Sun	60	—	unknown	02:45–05:05 (good, 2.33 h)	87.2° 08:45	7.35	86%	127.6°
2030-04-15 Mon	54	—	unknown	02:40–05:00 (good, 2.33 h)	87.2° 08:45	7.29	93%	126.1°
2030-04-16 Tue	53	—	unknown	02:40–05:00 (good, 2.33 h)	87.2° 08:40	7.23	98%	122.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-03-18&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.