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 Seven Sisters: 08-31 (100), 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100) — by astronomy; check the weather when the night is within four days.

2030-08-16astronomy score per night — click a bar for that night2030-09-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-08-16 Fri	16	—	unknown	02:20–04:50 (marginal, 2.5 h)	72.5° 07:25	6.7	86%	51.9°
2030-08-17 Sat	15	—	unknown	02:15–04:50 (marginal, 2.58 h)	72.5° 07:25	6.76	78%	39.3°
2030-08-18 Sun	16	—	unknown	02:05–04:50 (marginal, 2.75 h)	72.5° 07:20	6.82	70%	27.0°
2030-08-19 Mon	23	—	unknown	01:50–04:55 (marginal, 3.08 h)	72.5° 07:15	6.87	61%	15.1°
2030-08-20 Tue	31	—	unknown	04:20–04:55 (good, 0.58 h)	72.5° 07:10	6.93	51%	4.1°
2030-08-21 Wed	41	—	unknown	02:25–04:55 (good, 2.5 h)	72.5° 07:05	6.99	42%	9.4°
2030-08-22 Thu	52	—	unknown	02:10–05:00 (good, 2.83 h)	72.5° 07:05	7.05	33%	21.0°
2030-08-23 Fri	63	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 07:00	7.1	24%	32.9°
2030-08-24 Sat	76	—	unknown	01:50–05:00 (good, 3.17 h)	72.5° 06:55	7.16	16%	45.0°
2030-08-25 Sun	83	—	unknown	01:45–05:00 (good, 3.25 h)	72.5° 06:50	7.22	10%	57.3°
2030-08-26 Mon	90	—	unknown	01:40–05:05 (good, 3.42 h)	72.5° 06:50	7.27	5%	69.8°
2030-08-27 Tue	91	—	unknown	01:40–05:05 (good, 3.42 h)	72.5° 06:45	7.33	1%	82.7°
2030-08-28 Wed	94	—	unknown	01:35–05:05 (good, 3.5 h)	72.5° 06:40	7.39	0%	95.8°
2030-08-29 Thu	96	—	unknown	01:30–05:10 (good, 3.67 h)	72.5° 06:35	7.44	1%	109.2°
2030-08-30 Fri	98	—	unknown	01:25–05:10 (good, 3.75 h)	72.5° 06:30	7.5	5%	122.9°
2030-08-31 Sat	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.5° 06:30	7.56	11%	136.7°
2030-09-01 Sun	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.5° 06:25	7.61	18%	150.7°
2030-09-02 Mon	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.5° 06:20	7.67	28%	164.6°
2030-09-03 Tue	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.5° 06:15	7.72	39%	176.8°
2030-09-04 Wed	100	—	unknown	01:05–05:15 (good, 4.17 h)	72.5° 06:10	7.78	50%	166.4°
2030-09-05 Thu	100	—	unknown	01:00–05:15 (good, 4.25 h)	72.5° 06:10	7.83	62%	152.5°
2030-09-06 Fri	100	—	unknown	01:05–05:20 (good, 4.25 h)	72.5° 06:05	7.89	72%	138.4°
2030-09-07 Sat	100	—	unknown	01:00–05:20 (good, 4.33 h)	72.5° 06:00	7.94	82%	124.4°
2030-09-08 Sun	100	—	unknown	01:05–05:20 (good, 4.25 h)	72.5° 05:55	8.0	90%	110.5°
2030-09-09 Mon	98	—	unknown	01:15–05:25 (good, 4.17 h)	72.5° 05:55	8.05	95%	96.7°
2030-09-10 Tue	64	—	unknown	02:30–05:25 (good, 2.92 h)	72.5° 05:50	8.11	99%	83.1°
2030-09-11 Wed	47	—	unknown	04:10–05:25 (good, 1.25 h)	72.5° 05:45	8.16	100%	69.8°
2030-09-12 Thu	33	—	unknown	00:40–05:25 (marginal, 4.75 h)	72.5° 05:40	8.21	99%	56.7°
2030-09-13 Fri	23	—	unknown	00:50–05:30 (marginal, 4.67 h)	72.5° 05:35	8.27	95%	43.9°
2030-09-14 Sat	16	—	unknown	00:50–05:30 (marginal, 4.67 h)	72.5° 05:35	8.32	90%	31.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-08-16&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.