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: 05-20 (100), 05-21 (100), 05-22 (100), 05-23 (100), 05-24 (100) — by astronomy; check the weather when the night is within four days.

2047-04-30astronomy score per night — click a bar for that night2047-05-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-04-30 Tue	80	—	unknown	01:30–04:35 (good, 3.08 h)	87.2° 07:45	6.43	28%	107.5°
2047-05-01 Wed	80	—	unknown	01:30–04:30 (good, 3.0 h)	87.2° 07:40	6.37	37%	114.0°
2047-05-02 Thu	81	—	unknown	01:25–04:30 (good, 3.08 h)	87.1° 07:35	6.31	48%	119.6°
2047-05-03 Fri	81	—	unknown	01:25–04:30 (good, 3.08 h)	87.2° 07:35	6.25	58%	123.9°
2047-05-04 Sat	80	—	unknown	01:25–04:25 (good, 3.0 h)	87.2° 07:30	6.19	69%	126.3°
2047-05-05 Sun	81	—	unknown	01:20–04:25 (good, 3.08 h)	87.2° 07:25	6.14	79%	126.2°
2047-05-06 Mon	79	—	unknown	01:20–04:20 (good, 3.0 h)	87.2° 07:20	6.08	88%	123.5°
2047-05-07 Tue	72	—	unknown	01:15–04:20 (good, 3.08 h)	87.1° 07:20	6.02	95%	118.3°
2047-05-08 Wed	66	—	unknown	01:20–04:20 (good, 3.0 h)	87.2° 07:15	5.97	99%	111.3°
2047-05-09 Thu	60	—	unknown	01:20–04:15 (good, 2.92 h)	87.2° 07:10	5.91	100%	103.1°
2047-05-10 Fri	55	—	unknown	01:20–04:15 (good, 2.92 h)	87.2° 07:05	5.85	98%	94.3°
2047-05-11 Sat	51	—	unknown	01:20–04:15 (good, 2.92 h)	87.2° 07:00	5.8	93%	85.5°
2047-05-12 Sun	49	—	unknown	01:15–04:10 (good, 2.92 h)	87.2° 07:00	5.74	86%	77.1°
2047-05-13 Mon	53	—	unknown	01:05–04:10 (good, 3.08 h)	87.2° 06:55	5.69	78%	69.5°
2047-05-14 Tue	64	—	unknown	00:35–04:10 (good, 3.58 h)	87.2° 06:50	5.64	68%	63.1°
2047-05-15 Wed	71	—	unknown	00:30–04:05 (good, 3.58 h)	87.2° 06:45	5.58	58%	58.1°
2047-05-16 Thu	78	—	unknown	00:25–04:05 (good, 3.67 h)	87.1° 06:40	5.53	48%	54.8°
2047-05-17 Fri	85	—	unknown	00:25–04:05 (good, 3.67 h)	87.2° 06:40	5.48	38%	53.4°
2047-05-18 Sat	92	—	unknown	00:20–04:05 (good, 3.75 h)	87.2° 06:35	5.42	29%	53.9°
2047-05-19 Sun	96	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:30	5.37	21%	56.2°
2047-05-20 Mon	100	—	unknown	00:10–04:00 (good, 3.83 h)	87.2° 06:25	5.32	14%	60.0°
2047-05-21 Tue	100	—	unknown	00:05–04:00 (good, 3.92 h)	87.1° 06:25	5.27	8%	65.0°
2047-05-22 Wed	100	—	unknown	00:05–03:55 (good, 3.83 h)	87.2° 06:20	5.23	4%	70.9°
2047-05-23 Thu	100	—	unknown	00:00–03:55 (good, 3.92 h)	87.2° 06:15	5.18	1%	77.4°
2047-05-24 Fri	100	—	unknown	23:55–03:55 (good, 4.0 h)	87.2° 06:10	5.13	0%	84.4°
2047-05-25 Sat	100	—	unknown	23:50–03:55 (good, 4.08 h)	87.2° 06:05	5.09	1%	91.7°
2047-05-26 Sun	100	—	unknown	23:50–03:50 (good, 4.0 h)	87.2° 06:05	5.04	4%	99.0°
2047-05-27 Mon	100	—	unknown	23:45–03:50 (good, 4.08 h)	87.2° 06:00	5.0	9%	106.1°
2047-05-28 Tue	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:55	4.96	16%	112.7°
2047-05-29 Wed	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:50	4.91	24%	118.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-04-30&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.