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: 07-21 (100), 07-22 (100), 07-23 (100), 07-31 (100), 08-01 (100) — by astronomy; check the weather when the night is within four days.

2037-07-21astronomy score per night — click a bar for that night2037-08-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-07-21 Tue	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:20	5.29	73%	92.6°
2037-07-22 Wed	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:15	5.34	82%	86.1°
2037-07-23 Thu	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:15	5.39	90%	79.8°
2037-07-24 Fri	77	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:10	5.44	95%	74.1°
2037-07-25 Sat	70	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:05	5.49	98%	69.1°
2037-07-26 Sun	64	—	unknown	01:50–04:15 (good, 2.42 h)	87.2° 02:00	5.54	100%	65.1°
2037-07-27 Mon	62	—	unknown	22:40–00:15 (good, 1.58 h)	87.2° 01:55	5.6	99%	62.3°
2037-07-28 Tue	65	—	unknown	22:40–00:40 (good, 2.0 h)	87.2° 01:55	5.65	97%	60.9°
2037-07-29 Wed	69	—	unknown	22:40–01:35 (good, 2.92 h)	87.2° 01:50	5.7	93%	60.8°
2037-07-30 Thu	98	—	unknown	22:35–03:05 (good, 4.5 h)	87.2° 01:45	5.76	87%	62.2°
2037-07-31 Fri	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:40	5.81	80%	64.7°
2037-08-01 Sat	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:40	5.87	72%	68.3°
2037-08-02 Sun	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:35	5.92	63%	72.9°
2037-08-03 Mon	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:30	5.98	54%	78.1°
2037-08-04 Tue	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:25	6.03	44%	83.8°
2037-08-05 Wed	100	—	unknown	22:25–04:30 (good, 6.08 h)	87.2° 01:20	6.09	34%	90.0°
2037-08-06 Thu	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:20	6.15	25%	96.3°
2037-08-07 Fri	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:15	6.2	16%	102.6°
2037-08-08 Sat	100	—	unknown	22:20–04:35 (good, 6.25 h)	87.2° 01:10	6.26	9%	108.4°
2037-08-09 Sun	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:05	6.32	3%	113.5°
2037-08-10 Mon	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:00	6.37	0%	117.2°
2037-08-11 Tue	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.2° 01:00	6.43	0%	119.2°
2037-08-12 Wed	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.2° 00:55	6.49	3%	118.9°
2037-08-13 Thu	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:50	6.55	9%	116.6°
2037-08-14 Fri	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:45	6.6	17%	112.4°
2037-08-15 Sat	100	—	unknown	22:10–04:50 (good, 6.67 h)	87.2° 00:45	6.66	27%	107.0°
2037-08-16 Sun	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:40	6.72	38%	100.8°
2037-08-17 Mon	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:35	6.78	49%	94.2°
2037-08-18 Tue	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:30	6.83	60%	87.6°
2037-08-19 Wed	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.89	70%	81.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-07-21&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.