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: 08-09 (48), 08-10 (48), 08-08 (45), 08-07 (43), 08-11 (43) — by astronomy; check the weather when the night is within four days.

2030-07-21astronomy score per night — click a bar for that night2030-08-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-07-21 Sun	5	—	unknown	03:45–04:10 (marginal, 0.42 h)	72.5° 09:10	5.27	54%	35.0°
2030-07-22 Mon	6	—	unknown	03:35–04:10 (marginal, 0.58 h)	72.5° 09:05	5.32	44%	23.0°
2030-07-23 Tue	8	—	unknown	03:30–04:10 (marginal, 0.67 h)	72.5° 09:00	5.37	35%	11.2°
2030-07-24 Wed	12	—	unknown	04:05–04:15 (good, 0.17 h)	72.5° 08:55	5.42	26%	2.9°
2030-07-25 Thu	15	—	unknown	03:55–04:15 (good, 0.33 h)	72.5° 08:55	5.48	18%	13.1°
2030-07-26 Fri	18	—	unknown	03:50–04:15 (good, 0.42 h)	72.5° 08:50	5.53	12%	24.8°
2030-07-27 Sat	22	—	unknown	03:40–04:20 (good, 0.67 h)	72.5° 08:45	5.58	6%	36.8°
2030-07-28 Sun	24	—	unknown	03:35–04:20 (good, 0.75 h)	72.5° 08:40	5.63	2%	49.0°
2030-07-29 Mon	25	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:40	5.69	0%	61.4°
2030-07-30 Tue	27	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:35	5.74	0%	74.0°
2030-07-31 Wed	29	—	unknown	03:25–04:25 (good, 1.0 h)	72.5° 08:30	5.79	2%	86.8°
2030-08-01 Thu	31	—	unknown	03:20–04:25 (good, 1.08 h)	72.5° 08:25	5.85	7%	99.8°
2030-08-02 Fri	33	—	unknown	03:15–04:25 (good, 1.17 h)	72.5° 08:20	5.9	13%	113.1°
2030-08-03 Sat	35	—	unknown	03:10–04:30 (good, 1.33 h)	72.5° 08:20	5.96	21%	126.5°
2030-08-04 Sun	37	—	unknown	03:10–04:30 (good, 1.33 h)	72.5° 08:15	6.02	31%	140.1°
2030-08-05 Mon	39	—	unknown	03:05–04:30 (good, 1.42 h)	72.5° 08:10	6.07	41%	153.9°
2030-08-06 Tue	41	—	unknown	03:00–04:35 (good, 1.58 h)	72.5° 08:05	6.13	53%	167.8°
2030-08-07 Wed	43	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:00	6.19	64%	176.4°
2030-08-08 Thu	45	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:00	6.24	75%	163.1°
2030-08-09 Fri	48	—	unknown	02:50–04:40 (good, 1.83 h)	72.5° 07:55	6.3	84%	148.8°
2030-08-10 Sat	48	—	unknown	02:50–04:40 (good, 1.83 h)	72.5° 07:50	6.36	92%	134.4°
2030-08-11 Sun	43	—	unknown	02:50–04:40 (good, 1.83 h)	72.5° 07:45	6.41	97%	120.0°
2030-08-12 Mon	38	—	unknown	02:55–04:45 (good, 1.83 h)	72.5° 07:45	6.47	100%	105.8°
2030-08-13 Tue	31	—	unknown	03:30–04:45 (good, 1.25 h)	72.5° 07:40	6.53	100%	91.8°
2030-08-14 Wed	24	—	unknown	02:15–05:25 (marginal, 3.17 h)	72.5° 07:35	6.59	97%	78.2°
2030-08-15 Thu	19	—	unknown	02:15–04:50 (marginal, 2.58 h)	72.5° 07:30	6.64	92%	64.9°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-07-21&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.