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: 09-27 (100), 09-28 (100), 09-29 (100), 09-30 (100), 10-01 (100) — by astronomy; check the weather when the night is within four days.

2035-09-27astronomy score per night — click a bar for that night2035-10-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-09-27 Thu	100	—	unknown	20:45–04:15 (good, 7.5 h)	87.2° 21:55	8.98	16%	121.6°
2035-09-28 Fri	100	—	unknown	20:45–04:10 (good, 7.42 h)	87.2° 21:50	9.02	8%	122.5°
2035-09-29 Sat	100	—	unknown	20:40–04:10 (good, 7.5 h)	87.2° 21:50	9.07	3%	121.3°
2035-09-30 Sun	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.2° 21:45	9.12	0%	118.2°
2035-10-01 Mon	100	—	unknown	20:40–04:00 (good, 7.33 h)	87.2° 21:40	9.17	0%	113.5°
2035-10-02 Tue	100	—	unknown	20:35–03:55 (good, 7.33 h)	87.2° 21:35	9.22	2%	107.9°
2035-10-03 Wed	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.27	6%	101.6°
2035-10-04 Thu	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.31	12%	95.0°
2035-10-05 Fri	100	—	unknown	20:30–03:45 (good, 7.25 h)	87.2° 21:25	9.36	19%	88.4°
2035-10-06 Sat	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.41	27%	82.0°
2035-10-07 Sun	100	—	unknown	20:30–03:35 (good, 7.08 h)	87.2° 21:15	9.45	36%	76.0°
2035-10-08 Mon	100	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.5	45%	70.4°
2035-10-09 Tue	96	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.55	55%	65.5°
2035-10-10 Wed	90	—	unknown	20:25–03:25 (good, 7.0 h)	87.2° 21:05	9.59	64%	61.6°
2035-10-11 Thu	83	—	unknown	20:20–03:20 (good, 7.0 h)	87.2° 21:00	9.64	73%	58.9°
2035-10-12 Fri	63	—	unknown	20:20–01:20 (good, 5.0 h)	87.2° 20:55	9.68	81%	57.6°
2035-10-13 Sat	60	—	unknown	20:20–20:25 (good, 0.08 h)	87.2° 20:55	9.73	89%	58.1°
2035-10-14 Sun	60	—	unknown	20:15–20:20 (good, 0.08 h)	87.2° 20:50	9.77	94%	60.3°
2035-10-15 Mon	61	—	unknown	20:15–20:50 (good, 0.58 h)	87.2° 20:45	9.81	98%	64.3°
2035-10-16 Tue	67	—	unknown	20:15–21:50 (good, 1.58 h)	87.2° 20:40	9.86	100%	69.7°
2035-10-17 Wed	73	—	unknown	20:10–23:30 (good, 3.33 h)	87.2° 20:35	9.9	99%	76.2°
2035-10-18 Thu	79	—	unknown	20:10–00:30 (good, 4.33 h)	87.2° 20:35	9.94	96%	83.5°
2035-10-19 Fri	100	—	unknown	20:10–01:30 (good, 5.33 h)	87.2° 20:30	9.98	90%	91.2°
2035-10-20 Sat	100	—	unknown	20:10–02:15 (good, 6.08 h)	87.2° 20:25	10.03	82%	98.8°
2035-10-21 Sun	100	—	unknown	20:05–02:25 (good, 6.33 h)	87.2° 20:20	10.07	72%	106.0°
2035-10-22 Mon	100	—	unknown	20:05–02:25 (good, 6.33 h)	87.2° 20:15	10.11	61%	112.4°
2035-10-23 Tue	100	—	unknown	20:05–02:25 (good, 6.33 h)	87.2° 20:15	10.15	50%	117.4°
2035-10-24 Wed	100	—	unknown	20:00–02:25 (good, 6.42 h)	87.2° 20:10	10.19	38%	120.9°
2035-10-25 Thu	100	—	unknown	20:00–02:25 (good, 6.42 h)	87.2° 20:05	10.23	28%	122.3°
2035-10-26 Fri	100	—	unknown	20:00–02:20 (good, 6.33 h)	87.2° 20:00	10.27	19%	121.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-09-27&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.