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: 05-27 (100), 05-28 (100), 05-29 (100), 05-30 (100), 05-31 (100) — by astronomy; check the weather when the night is within four days.

2038-05-19astronomy score per night — click a bar for that night2038-06-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-05-19 Wed	52	—	unknown	01:25–04:00 (good, 2.58 h)	87.2° 06:30	5.37	98%	85.0°
2038-05-20 Thu	51	—	unknown	01:15–04:00 (good, 2.75 h)	87.2° 06:25	5.32	94%	78.5°
2038-05-21 Fri	54	—	unknown	00:40–04:00 (good, 3.33 h)	87.2° 06:20	5.27	87%	72.6°
2038-05-22 Sat	67	—	unknown	00:05–03:55 (good, 3.83 h)	87.2° 06:20	5.22	78%	67.9°
2038-05-23 Sun	78	—	unknown	00:00–03:55 (good, 3.92 h)	87.2° 06:15	5.17	69%	64.4°
2038-05-24 Mon	88	—	unknown	23:55–03:55 (good, 4.0 h)	87.2° 06:10	5.12	59%	62.4°
2038-05-25 Tue	95	—	unknown	23:50–03:55 (good, 4.08 h)	87.2° 06:05	5.08	49%	61.8°
2038-05-26 Wed	99	—	unknown	23:45–03:50 (good, 4.08 h)	87.2° 06:00	5.03	40%	62.6°
2038-05-27 Thu	100	—	unknown	23:45–03:50 (good, 4.08 h)	87.2° 06:00	4.99	31%	64.7°
2038-05-28 Fri	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:55	4.95	22%	67.9°
2038-05-29 Sat	100	—	unknown	23:35–03:50 (good, 4.25 h)	87.2° 05:50	4.91	15%	71.9°
2038-05-30 Sun	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.2° 05:45	4.87	9%	76.6°
2038-05-31 Mon	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.2° 05:40	4.83	4%	81.9°
2038-06-01 Tue	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.2° 05:40	4.79	1%	87.5°
2038-06-02 Wed	100	—	unknown	23:20–03:45 (good, 4.42 h)	87.2° 05:35	4.76	0%	93.2°
2038-06-03 Thu	100	—	unknown	23:15–03:45 (good, 4.5 h)	87.2° 05:30	4.72	1%	98.9°
2038-06-04 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 05:25	4.69	4%	104.4°
2038-06-05 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:25	4.66	8%	109.3°
2038-06-06 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:20	4.63	15%	113.4°
2038-06-07 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:15	4.6	23%	116.4°
2038-06-08 Tue	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:10	4.58	33%	118.0°
2038-06-09 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:05	4.55	44%	117.8°
2038-06-10 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:05	4.53	55%	115.9°
2038-06-11 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:00	4.51	66%	112.4°
2038-06-12 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:55	4.49	77%	107.5°
2038-06-13 Sun	87	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:50	4.48	86%	101.5°
2038-06-14 Mon	82	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:45	4.46	93%	94.8°
2038-06-15 Tue	72	—	unknown	23:35–03:40 (good, 4.08 h)	87.2° 04:45	4.45	98%	87.9°
2038-06-16 Wed	64	—	unknown	23:55–03:40 (good, 3.75 h)	87.2° 04:40	4.44	100%	81.2°
2038-06-17 Thu	59	—	unknown	00:00–03:40 (good, 3.67 h)	87.2° 04:35	4.43	99%	75.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-05-19&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.