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: 10-17 (100), 10-18 (100), 10-19 (100), 10-20 (100), 10-21 (100) — by astronomy; check the weather when the night is within four days.

2031-10-17astronomy score per night — click a bar for that night2031-11-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-10-17 Fri	100	—	unknown	20:10–02:55 (good, 6.75 h)	87.2° 20:35	9.9	3%	103.7°
2031-10-18 Sat	100	—	unknown	20:10–02:55 (good, 6.75 h)	87.2° 20:35	9.94	8%	95.6°
2031-10-19 Sun	100	—	unknown	20:10–02:50 (good, 6.67 h)	87.2° 20:30	9.98	15%	87.1°
2031-10-20 Mon	100	—	unknown	20:10–02:45 (good, 6.58 h)	87.2° 20:25	10.02	24%	78.6°
2031-10-21 Tue	100	—	unknown	20:05–02:40 (good, 6.58 h)	87.2° 20:20	10.07	34%	70.6°
2031-10-22 Wed	94	—	unknown	20:05–02:35 (good, 6.5 h)	87.2° 20:15	10.11	46%	63.5°
2031-10-23 Thu	86	—	unknown	20:05–02:35 (good, 6.5 h)	87.2° 20:15	10.15	57%	57.7°
2031-10-24 Fri	70	—	unknown	20:00–02:00 (good, 6.0 h)	87.2° 20:10	10.19	68%	53.9°
2031-10-25 Sat	59	—	unknown	20:00–03:00 (marginal, 7.0 h)	87.2° 20:05	10.23	78%	52.5°
2031-10-26 Sun	50	—	unknown	19:00–01:45 (marginal, 6.75 h)	87.2° 19:00	10.27	87%	53.7°
2031-10-27 Mon	47	—	unknown	19:00–01:30 (marginal, 6.5 h)	87.2° 19:00	10.31	93%	57.3°
2031-10-28 Tue	50	—	unknown	18:55–01:20 (marginal, 6.42 h)	87.2° 18:55	10.34	98%	62.6°
2031-10-29 Wed	57	—	unknown	18:55–19:50 (good, 0.92 h)	87.2° 18:50	10.38	100%	69.2°
2031-10-30 Thu	68	—	unknown	18:55–21:35 (good, 2.67 h)	87.2° 18:45	10.42	100%	76.6°
2031-10-31 Fri	77	—	unknown	18:55–22:35 (good, 3.67 h)	87.2° 18:40	10.46	97%	84.2°
2031-11-01 Sat	83	—	unknown	18:55–23:35 (good, 4.67 h)	87.2° 18:40	10.49	93%	91.9°
2031-11-02 Sun	100	—	unknown	18:50–00:25 (good, 5.58 h)	87.2° 18:35	10.53	87%	99.4°
2031-11-03 Mon	100	—	unknown	18:50–00:30 (good, 5.67 h)	87.2° 18:30	10.57	80%	106.4°
2031-11-04 Tue	100	—	unknown	18:50–00:35 (good, 5.75 h)	87.2° 18:25	10.6	72%	112.8°
2031-11-05 Wed	100	—	unknown	18:50–00:35 (good, 5.75 h)	87.2° 18:20	10.64	63%	118.4°
2031-11-06 Thu	100	—	unknown	18:45–00:35 (good, 5.83 h)	87.2° 18:20	10.67	54%	122.9°
2031-11-07 Fri	100	—	unknown	18:45–00:30 (good, 5.75 h)	87.2° 18:15	10.7	44%	126.0°
2031-11-08 Sat	100	—	unknown	18:45–00:30 (good, 5.75 h)	87.2° 18:10	10.74	35%	127.4°
2031-11-09 Sun	100	—	unknown	18:45–00:25 (good, 5.67 h)	87.2° 18:05	10.77	26%	126.9°
2031-11-10 Mon	100	—	unknown	18:45–00:25 (good, 5.67 h)	87.2° 18:00	10.8	17%	124.4°
2031-11-11 Tue	100	—	unknown	18:45–00:20 (good, 5.58 h)	87.2° 18:00	10.83	10%	120.0°
2031-11-12 Wed	100	—	unknown	18:40–00:15 (good, 5.58 h)	87.2° 17:55	10.86	5%	114.0°
2031-11-13 Thu	100	—	unknown	18:40–00:10 (good, 5.5 h)	87.2° 17:50	10.89	1%	106.7°
2031-11-14 Fri	100	—	unknown	18:40–00:05 (good, 5.42 h)	87.2° 17:45	10.92	0%	98.6°
2031-11-15 Sat	100	—	unknown	18:40–00:05 (good, 5.42 h)	87.2° 17:45	10.95	1%	89.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-10-17&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.