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: 04-30 (78), 04-27 (77), 04-29 (77), 05-01 (77), 04-28 (76) — by astronomy; check the weather when the night is within four days.

2031-04-02astronomy score per night — click a bar for that night2031-05-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-04-02 Wed	52	—	unknown	03:30–05:30 (good, 2.0 h)	87.2° 09:35	8.04	76%	124.1°
2031-04-03 Thu	51	—	unknown	03:25–05:25 (good, 2.0 h)	87.2° 09:30	7.98	84%	126.8°
2031-04-04 Fri	51	—	unknown	03:25–05:25 (good, 2.0 h)	87.2° 09:25	7.93	91%	127.5°
2031-04-05 Sat	45	—	unknown	03:20–05:20 (good, 2.0 h)	87.2° 09:25	7.87	96%	126.0°
2031-04-06 Sun	46	—	unknown	03:20–05:20 (good, 2.0 h)	87.2° 09:20	7.82	99%	122.4°
2031-04-07 Mon	45	—	unknown	03:15–05:20 (good, 2.08 h)	87.2° 09:15	7.76	100%	116.8°
2031-04-08 Tue	41	—	unknown	03:20–05:15 (good, 1.92 h)	87.2° 09:10	7.7	98%	109.8°
2031-04-09 Wed	38	—	unknown	03:20–05:15 (good, 1.92 h)	87.2° 09:10	7.65	94%	101.7°
2031-04-10 Thu	36	—	unknown	03:15–05:10 (good, 1.92 h)	87.2° 09:05	7.59	87%	93.1°
2031-04-11 Fri	36	—	unknown	03:15–05:10 (good, 1.92 h)	87.2° 09:00	7.53	78%	84.4°
2031-04-12 Sat	38	—	unknown	03:05–05:10 (good, 2.08 h)	87.2° 08:55	7.48	68%	75.9°
2031-04-13 Sun	41	—	unknown	02:55–05:05 (good, 2.17 h)	87.2° 08:50	7.42	57%	68.1°
2031-04-14 Mon	46	—	unknown	02:35–05:05 (good, 2.5 h)	87.2° 08:50	7.36	46%	61.3°
2031-04-15 Tue	54	—	unknown	02:30–05:00 (good, 2.5 h)	87.2° 08:45	7.31	34%	56.2°
2031-04-16 Wed	59	—	unknown	02:25–05:00 (good, 2.58 h)	87.2° 08:40	7.25	24%	53.1°
2031-04-17 Thu	65	—	unknown	02:20–05:00 (good, 2.67 h)	87.2° 08:35	7.19	16%	52.5°
2031-04-18 Fri	67	—	unknown	02:15–04:55 (good, 2.67 h)	87.2° 08:30	7.13	8%	54.3°
2031-04-19 Sat	68	—	unknown	02:15–04:55 (good, 2.67 h)	87.2° 08:30	7.07	4%	58.1°
2031-04-20 Sun	70	—	unknown	02:10–04:55 (good, 2.75 h)	87.2° 08:25	7.02	1%	63.6°
2031-04-21 Mon	70	—	unknown	02:05–04:50 (good, 2.75 h)	87.2° 08:20	6.96	0%	70.1°
2031-04-22 Tue	72	—	unknown	02:00–04:50 (good, 2.83 h)	87.2° 08:15	6.9	2%	77.2°
2031-04-23 Wed	71	—	unknown	02:00–04:45 (good, 2.75 h)	87.2° 08:15	6.84	5%	84.6°
2031-04-24 Thu	73	—	unknown	01:55–04:45 (good, 2.83 h)	87.2° 08:10	6.78	10%	92.0°
2031-04-25 Fri	75	—	unknown	01:50–04:45 (good, 2.92 h)	87.2° 08:05	6.72	16%	99.2°
2031-04-26 Sat	75	—	unknown	01:45–04:40 (good, 2.92 h)	87.2° 08:00	6.67	24%	106.2°
2031-04-27 Sun	77	—	unknown	01:40–04:40 (good, 3.0 h)	87.2° 07:55	6.61	32%	112.6°
2031-04-28 Mon	76	—	unknown	01:40–04:35 (good, 2.92 h)	87.2° 07:55	6.55	42%	118.3°
2031-04-29 Tue	77	—	unknown	01:40–04:35 (good, 2.92 h)	87.2° 07:50	6.49	51%	122.9°
2031-04-30 Wed	78	—	unknown	01:35–04:35 (good, 3.0 h)	87.2° 07:45	6.43	61%	126.2°
2031-05-01 Thu	77	—	unknown	01:35–04:30 (good, 2.92 h)	87.2° 07:40	6.38	70%	127.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-04-02&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.