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: 05-17 (100), 05-18 (100), 05-19 (100), 05-20 (100), 05-21 (100) — by astronomy; check the weather when the night is within four days.

2045-04-26astronomy score per night — click a bar for that night2045-05-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-04-26 Wed	71	—	unknown	01:55–04:40 (good, 2.75 h)	87.2° 08:00	6.63	78%	123.5°
2045-04-27 Thu	72	—	unknown	01:50–04:40 (good, 2.83 h)	87.2° 07:55	6.57	87%	123.3°
2045-04-28 Fri	65	—	unknown	01:50–04:35 (good, 2.75 h)	87.2° 07:50	6.51	94%	120.8°
2045-04-29 Sat	63	—	unknown	01:50–04:35 (good, 2.75 h)	87.2° 07:45	6.46	98%	116.5°
2045-04-30 Sun	58	—	unknown	01:50–04:30 (good, 2.67 h)	87.2° 07:45	6.4	100%	110.8°
2045-05-01 Mon	55	—	unknown	01:50–04:30 (good, 2.67 h)	87.2° 07:40	6.34	99%	104.3°
2045-05-02 Tue	52	—	unknown	01:45–04:30 (good, 2.75 h)	87.2° 07:35	6.28	97%	97.4°
2045-05-03 Wed	50	—	unknown	01:45–04:25 (good, 2.67 h)	87.2° 07:30	6.22	92%	90.4°
2045-05-04 Thu	50	—	unknown	01:40–04:25 (good, 2.75 h)	87.2° 07:30	6.17	86%	83.5°
2045-05-05 Fri	52	—	unknown	01:35–04:25 (good, 2.83 h)	87.2° 07:25	6.11	78%	77.0°
2045-05-06 Sat	59	—	unknown	01:05–04:20 (good, 3.25 h)	87.2° 07:20	6.05	70%	70.9°
2045-05-07 Sun	65	—	unknown	01:00–04:20 (good, 3.33 h)	87.2° 07:15	6.0	61%	65.6°
2045-05-08 Mon	72	—	unknown	00:55–04:20 (good, 3.42 h)	87.2° 07:10	5.94	52%	61.3°
2045-05-09 Tue	77	—	unknown	00:55–04:15 (good, 3.33 h)	87.2° 07:10	5.88	42%	58.1°
2045-05-10 Wed	83	—	unknown	00:50–04:15 (good, 3.42 h)	87.2° 07:05	5.83	33%	56.4°
2045-05-11 Thu	88	—	unknown	00:45–04:15 (good, 3.5 h)	87.2° 07:00	5.77	24%	56.4°
2045-05-12 Fri	93	—	unknown	00:40–04:10 (good, 3.5 h)	87.2° 06:55	5.72	16%	58.1°
2045-05-13 Sat	96	—	unknown	00:35–04:10 (good, 3.58 h)	87.2° 06:50	5.66	10%	61.5°
2045-05-14 Sun	96	—	unknown	00:35–04:10 (good, 3.58 h)	87.2° 06:50	5.61	4%	66.5°
2045-05-15 Mon	97	—	unknown	00:30–04:05 (good, 3.58 h)	87.2° 06:45	5.56	1%	72.8°
2045-05-16 Tue	99	—	unknown	00:25–04:05 (good, 3.67 h)	87.2° 06:40	5.5	0%	79.9°
2045-05-17 Wed	100	—	unknown	00:20–04:05 (good, 3.75 h)	87.2° 06:35	5.45	2%	87.7°
2045-05-18 Thu	100	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:35	5.4	6%	95.6°
2045-05-19 Fri	100	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:30	5.35	13%	103.4°
2045-05-20 Sat	100	—	unknown	00:10–04:00 (good, 3.83 h)	87.2° 06:25	5.3	22%	110.5°
2045-05-21 Sun	100	—	unknown	00:10–04:00 (good, 3.83 h)	87.2° 06:20	5.25	32%	116.6°
2045-05-22 Mon	100	—	unknown	00:05–03:55 (good, 3.83 h)	87.2° 06:15	5.2	43%	121.0°
2045-05-23 Tue	100	—	unknown	00:05–03:55 (good, 3.83 h)	87.2° 06:15	5.16	55%	123.5°
2045-05-24 Wed	100	—	unknown	00:00–03:55 (good, 3.92 h)	87.2° 06:10	5.11	66%	123.7°
2045-05-25 Thu	100	—	unknown	00:00–03:50 (good, 3.83 h)	87.2° 06:05	5.06	76%	121.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-04-26&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.