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 (80), 04-29 (78), 04-28 (77), 04-27 (73), 04-26 (65) — by astronomy; check the weather when the night is within four days.

2038-04-01astronomy score per night — click a bar for that night2038-04-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-04-01 Thu	52	—	unknown	03:25–05:30 (good, 2.08 h)	87.2° 09:40	8.08	7%	61.7°
2038-04-02 Fri	52	—	unknown	03:20–05:25 (good, 2.08 h)	87.2° 09:35	8.02	3%	63.3°
2038-04-03 Sat	54	—	unknown	03:15–05:25 (good, 2.17 h)	87.2° 09:30	7.97	1%	66.0°
2038-04-04 Sun	56	—	unknown	03:10–05:25 (good, 2.25 h)	87.2° 09:25	7.91	0%	69.7°
2038-04-05 Mon	56	—	unknown	03:05–05:20 (good, 2.25 h)	87.2° 09:25	7.86	2%	74.2°
2038-04-06 Tue	57	—	unknown	03:05–05:20 (good, 2.25 h)	87.2° 09:20	7.8	5%	79.3°
2038-04-07 Wed	58	—	unknown	03:00–05:20 (good, 2.33 h)	87.2° 09:15	7.74	9%	84.8°
2038-04-08 Thu	58	—	unknown	02:55–05:15 (good, 2.33 h)	87.2° 09:10	7.69	16%	90.5°
2038-04-09 Fri	60	—	unknown	02:50–05:15 (good, 2.42 h)	87.2° 09:05	7.63	23%	96.2°
2038-04-10 Sat	59	—	unknown	02:50–05:10 (good, 2.33 h)	87.2° 09:05	7.57	32%	101.9°
2038-04-11 Sun	61	—	unknown	02:45–05:10 (good, 2.42 h)	87.2° 09:00	7.52	42%	107.1°
2038-04-12 Mon	62	—	unknown	02:45–05:10 (good, 2.42 h)	87.2° 08:55	7.46	52%	111.8°
2038-04-13 Tue	60	—	unknown	02:45–05:05 (good, 2.33 h)	87.2° 08:50	7.4	62%	115.5°
2038-04-14 Wed	61	—	unknown	02:40–05:05 (good, 2.42 h)	87.2° 08:45	7.35	73%	117.8°
2038-04-15 Thu	55	—	unknown	02:40–05:00 (good, 2.33 h)	87.2° 08:45	7.29	82%	118.4°
2038-04-16 Fri	53	—	unknown	02:40–05:00 (good, 2.33 h)	87.2° 08:40	7.23	90%	117.1°
2038-04-17 Sat	51	—	unknown	02:40–05:00 (good, 2.33 h)	87.2° 08:35	7.17	96%	113.8°
2038-04-18 Sun	47	—	unknown	02:40–04:55 (good, 2.25 h)	87.2° 08:30	7.11	99%	108.9°
2038-04-19 Mon	43	—	unknown	02:40–04:55 (good, 2.25 h)	87.2° 08:30	7.06	100%	102.7°
2038-04-20 Tue	40	—	unknown	02:40–04:50 (good, 2.17 h)	87.2° 08:25	7.0	96%	95.8°
2038-04-21 Wed	40	—	unknown	02:40–04:50 (good, 2.17 h)	87.2° 08:20	6.94	91%	88.8°
2038-04-22 Thu	40	—	unknown	02:30–04:50 (good, 2.33 h)	87.2° 08:15	6.88	83%	82.0°
2038-04-23 Fri	43	—	unknown	02:25–04:45 (good, 2.33 h)	87.2° 08:10	6.82	74%	75.8°
2038-04-24 Sat	48	—	unknown	02:15–04:45 (good, 2.5 h)	87.2° 08:10	6.77	64%	70.5°
2038-04-25 Sun	57	—	unknown	01:50–04:40 (good, 2.83 h)	87.2° 08:05	6.71	53%	66.3°
2038-04-26 Mon	65	—	unknown	01:45–04:40 (good, 2.92 h)	87.2° 08:00	6.65	43%	63.4°
2038-04-27 Tue	73	—	unknown	01:40–04:40 (good, 3.0 h)	87.2° 07:55	6.59	34%	61.9°
2038-04-28 Wed	77	—	unknown	01:35–04:35 (good, 3.0 h)	87.2° 07:50	6.53	25%	61.7°
2038-04-29 Thu	78	—	unknown	01:35–04:35 (good, 3.0 h)	87.2° 07:50	6.47	17%	62.9°
2038-04-30 Fri	80	—	unknown	01:30–04:35 (good, 3.08 h)	87.2° 07:45	6.42	11%	65.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-04-01&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.