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: 05-05 (84), 05-02 (82), 05-03 (82), 05-04 (82), 05-06 (82) — by astronomy; check the weather when the night is within four days.

2044-04-15astronomy score per night — click a bar for that night2044-05-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-04-15 Fri	42	—	unknown	02:50–05:00 (good, 2.17 h)	87.2° 08:40	7.26	88%	95.8°
2044-04-16 Sat	43	—	unknown	02:45–05:00 (good, 2.25 h)	87.2° 08:35	7.2	81%	89.5°
2044-04-17 Sun	43	—	unknown	02:40–04:55 (good, 2.25 h)	87.2° 08:35	7.14	73%	83.2°
2044-04-18 Mon	47	—	unknown	02:15–04:55 (good, 2.67 h)	87.2° 08:30	7.08	65%	77.2°
2044-04-19 Tue	54	—	unknown	02:10–04:55 (good, 2.75 h)	87.2° 08:25	7.02	55%	71.6°
2044-04-20 Wed	59	—	unknown	02:05–04:50 (good, 2.75 h)	87.2° 08:20	6.97	46%	66.6°
2044-04-21 Thu	65	—	unknown	02:00–04:50 (good, 2.83 h)	87.2° 08:20	6.91	36%	62.5°
2044-04-22 Fri	68	—	unknown	02:00–04:45 (good, 2.75 h)	87.2° 08:15	6.85	27%	59.5°
2044-04-23 Sat	73	—	unknown	01:55–04:45 (good, 2.83 h)	87.2° 08:10	6.79	18%	58.1°
2044-04-24 Sun	74	—	unknown	01:50–04:45 (good, 2.92 h)	87.2° 08:05	6.73	11%	58.5°
2044-04-25 Mon	75	—	unknown	01:45–04:40 (good, 2.92 h)	87.2° 08:00	6.67	5%	61.0°
2044-04-26 Tue	76	—	unknown	01:45–04:40 (good, 2.92 h)	87.2° 08:00	6.62	1%	65.3°
2044-04-27 Wed	77	—	unknown	01:40–04:40 (good, 3.0 h)	87.2° 07:55	6.56	0%	71.1°
2044-04-28 Thu	78	—	unknown	01:35–04:35 (good, 3.0 h)	87.2° 07:50	6.5	2%	78.1°
2044-04-29 Fri	80	—	unknown	01:30–04:35 (good, 3.08 h)	87.2° 07:45	6.44	6%	85.7°
2044-04-30 Sat	80	—	unknown	01:25–04:30 (good, 3.08 h)	87.2° 07:40	6.38	14%	93.6°
2044-05-01 Sun	81	—	unknown	01:25–04:30 (good, 3.08 h)	87.2° 07:40	6.33	23%	101.1°
2044-05-02 Mon	82	—	unknown	01:25–04:30 (good, 3.08 h)	87.2° 07:35	6.27	33%	108.1°
2044-05-03 Tue	82	—	unknown	01:20–04:25 (good, 3.08 h)	87.2° 07:30	6.21	44%	113.9°
2044-05-04 Wed	82	—	unknown	01:20–04:25 (good, 3.08 h)	87.2° 07:25	6.15	56%	118.4°
2044-05-05 Thu	84	—	unknown	01:15–04:25 (good, 3.17 h)	87.2° 07:25	6.1	66%	121.2°
2044-05-06 Fri	82	—	unknown	01:15–04:20 (good, 3.08 h)	87.2° 07:20	6.04	76%	122.0°
2044-05-07 Sat	82	—	unknown	01:10–04:20 (good, 3.17 h)	87.2° 07:15	5.98	84%	121.0°
2044-05-08 Sun	75	—	unknown	01:10–04:20 (good, 3.17 h)	87.2° 07:10	5.93	91%	118.4°
2044-05-09 Mon	71	—	unknown	01:10–04:15 (good, 3.08 h)	87.2° 07:05	5.87	96%	114.4°
2044-05-10 Tue	67	—	unknown	01:10–04:15 (good, 3.08 h)	87.2° 07:05	5.81	99%	109.4°
2044-05-11 Wed	64	—	unknown	01:10–04:15 (good, 3.08 h)	87.2° 07:00	5.76	100%	103.7°
2044-05-12 Thu	59	—	unknown	01:05–04:10 (good, 3.08 h)	87.2° 06:55	5.7	99%	97.5°
2044-05-13 Fri	57	—	unknown	01:05–04:10 (good, 3.08 h)	87.2° 06:50	5.65	96%	91.2°
2044-05-14 Sat	56	—	unknown	01:00–04:10 (good, 3.17 h)	87.2° 06:45	5.6	92%	84.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-04-15&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.