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: 08-21 (100), 08-22 (100), 08-23 (100), 08-24 (100), 08-25 (100) — by astronomy; check the weather when the night is within four days.

2030-08-21astronomy score per night — click a bar for that night2030-09-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-08-21 Wed	100	—	unknown	21:55–04:55 (good, 7.0 h)	87.2° 00:20	6.99	42%	89.1°
2030-08-22 Thu	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.05	33%	96.3°
2030-08-23 Fri	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:10	7.1	24%	103.4°
2030-08-24 Sat	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:10	7.16	16%	110.2°
2030-08-25 Sun	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:05	7.22	10%	116.4°
2030-08-26 Mon	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 00:00	7.27	5%	121.6°
2030-08-27 Tue	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:55	7.33	1%	125.4°
2030-08-28 Wed	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:50	7.39	0%	127.4°
2030-08-29 Thu	100	—	unknown	21:40–05:10 (good, 7.5 h)	87.2° 23:50	7.44	1%	127.0°
2030-08-30 Fri	100	—	unknown	21:40–05:10 (good, 7.5 h)	87.2° 23:45	7.5	5%	124.2°
2030-08-31 Sat	100	—	unknown	21:35–05:10 (good, 7.58 h)	87.2° 23:40	7.56	11%	119.3°
2030-09-01 Sun	100	—	unknown	21:35–05:10 (good, 7.58 h)	87.2° 23:35	7.61	18%	112.8°
2030-09-02 Mon	100	—	unknown	21:35–05:15 (good, 7.67 h)	87.2° 23:35	7.67	28%	105.1°
2030-09-03 Tue	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:30	7.72	39%	96.8°
2030-09-04 Wed	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:25	7.78	50%	88.2°
2030-09-05 Thu	100	—	unknown	21:25–05:15 (good, 7.83 h)	87.2° 23:20	7.83	62%	79.7°
2030-09-06 Fri	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.89	72%	71.6°
2030-09-07 Sat	94	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.94	82%	64.4°
2030-09-08 Sun	85	—	unknown	00:20–05:20 (good, 5.0 h)	87.2° 23:10	8.0	90%	58.5°
2030-09-09 Mon	68	—	unknown	05:10–05:25 (good, 0.25 h)	87.2° 23:05	8.05	95%	54.4°
2030-09-10 Tue	54	—	unknown	21:15–05:25 (marginal, 8.17 h)	87.2° 23:00	8.11	99%	52.6°
2030-09-11 Wed	56	—	unknown	21:15–05:25 (marginal, 8.17 h)	87.2° 22:55	8.16	100%	53.2°
2030-09-12 Thu	60	—	unknown	21:15–21:20 (good, 0.08 h)	87.2° 22:55	8.21	99%	56.0°
2030-09-13 Fri	66	—	unknown	21:10–22:30 (good, 1.33 h)	87.2° 22:50	8.27	95%	60.5°
2030-09-14 Sat	73	—	unknown	21:10–00:15 (good, 3.08 h)	87.2° 22:45	8.32	90%	66.2°
2030-09-15 Sun	79	—	unknown	21:10–02:05 (good, 4.92 h)	87.2° 22:40	8.37	84%	72.7°
2030-09-16 Mon	100	—	unknown	21:05–03:15 (good, 6.17 h)	87.2° 22:40	8.43	76%	79.7°
2030-09-17 Tue	100	—	unknown	21:05–04:20 (good, 7.25 h)	87.2° 22:35	8.48	68%	86.9°
2030-09-18 Wed	100	—	unknown	21:00–04:25 (good, 7.42 h)	87.2° 22:30	8.53	58%	94.1°
2030-09-19 Thu	100	—	unknown	21:00–04:30 (good, 7.5 h)	87.2° 22:25	8.58	49%	101.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-08-21&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.