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: 09-16 (100), 09-17 (100), 09-27 (100), 09-28 (100), 09-29 (100) — by astronomy; check the weather when the night is within four days.

2037-09-16astronomy score per night — click a bar for that night2037-10-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-09-16 Wed	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.2° 22:35	8.44	55%	77.0°
2037-09-17 Thu	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.2° 22:35	8.49	65%	71.7°
2037-09-18 Fri	95	—	unknown	21:00–04:50 (good, 7.83 h)	87.2° 22:30	8.55	74%	67.2°
2037-09-19 Sat	88	—	unknown	21:00–04:45 (good, 7.75 h)	87.2° 22:25	8.6	82%	63.7°
2037-09-20 Sun	82	—	unknown	20:55–04:40 (good, 7.75 h)	87.2° 22:20	8.65	89%	61.6°
2037-09-21 Mon	62	—	unknown	20:55–21:35 (good, 0.67 h)	87.2° 22:15	8.7	94%	60.7°
2037-09-22 Tue	62	—	unknown	20:55–21:30 (good, 0.58 h)	87.2° 22:15	8.75	98%	61.2°
2037-09-23 Wed	64	—	unknown	20:50–21:50 (good, 1.0 h)	87.2° 22:10	8.8	100%	63.1°
2037-09-24 Thu	67	—	unknown	20:50–22:30 (good, 1.67 h)	87.2° 22:05	8.85	100%	66.1°
2037-09-25 Fri	71	—	unknown	20:50–23:35 (good, 2.75 h)	87.2° 22:00	8.9	98%	70.1°
2037-09-26 Sat	76	—	unknown	20:45–01:00 (good, 4.25 h)	87.2° 21:55	8.95	94%	74.9°
2037-09-27 Sun	100	—	unknown	20:45–01:50 (good, 5.08 h)	87.2° 21:55	9.0	89%	80.3°
2037-09-28 Mon	100	—	unknown	20:45–02:40 (good, 5.92 h)	87.2° 21:50	9.05	83%	86.1°
2037-09-29 Tue	100	—	unknown	20:40–03:35 (good, 6.92 h)	87.2° 21:45	9.1	75%	92.1°
2037-09-30 Wed	100	—	unknown	20:40–03:40 (good, 7.0 h)	87.2° 21:40	9.15	66%	98.2°
2037-10-01 Thu	100	—	unknown	20:35–03:45 (good, 7.17 h)	87.2° 21:40	9.2	55%	104.0°
2037-10-02 Fri	100	—	unknown	20:35–03:45 (good, 7.17 h)	87.2° 21:35	9.24	45%	109.4°
2037-10-03 Sat	100	—	unknown	20:35–03:45 (good, 7.17 h)	87.2° 21:30	9.29	34%	114.0°
2037-10-04 Sun	100	—	unknown	20:30–03:45 (good, 7.25 h)	87.2° 21:25	9.34	24%	117.4°
2037-10-05 Mon	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.38	15%	119.1°
2037-10-06 Tue	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.43	7%	118.7°
2037-10-07 Wed	100	—	unknown	20:25–03:35 (good, 7.17 h)	87.2° 21:15	9.48	2%	116.2°
2037-10-08 Thu	100	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.52	0%	111.9°
2037-10-09 Fri	100	—	unknown	20:25–03:25 (good, 7.0 h)	87.2° 21:05	9.57	1%	106.1°
2037-10-10 Sat	100	—	unknown	20:20–03:25 (good, 7.08 h)	87.2° 21:00	9.61	5%	99.5°
2037-10-11 Sun	100	—	unknown	20:20–03:20 (good, 7.0 h)	87.2° 21:00	9.66	11%	92.5°
2037-10-12 Mon	100	—	unknown	20:20–03:15 (good, 6.92 h)	87.2° 20:55	9.7	20%	85.6°
2037-10-13 Tue	100	—	unknown	20:15–03:10 (good, 6.92 h)	87.2° 20:50	9.75	29%	79.2°
2037-10-14 Wed	100	—	unknown	20:15–03:05 (good, 6.83 h)	87.2° 20:45	9.79	39%	73.4°
2037-10-15 Thu	97	—	unknown	20:15–03:05 (good, 6.83 h)	87.2° 20:45	9.84	49%	68.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-09-16&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.