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: 08-29 (95), 08-30 (94), 08-28 (93), 08-27 (91), 08-26 (89) — by astronomy; check the weather when the night is within four days.

2039-08-09astronomy score per night — click a bar for that night2039-09-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-08-09 Tue	14	—	unknown	02:35–04:40 (marginal, 2.08 h)	72.5° 07:55	6.29	68%	34.6°
2039-08-10 Wed	18	—	unknown	02:25–04:40 (marginal, 2.25 h)	72.5° 07:50	6.35	58%	22.6°
2039-08-11 Thu	23	—	unknown	04:25–04:40 (good, 0.25 h)	72.5° 07:50	6.4	49%	11.5°
2039-08-12 Fri	31	—	unknown	03:00–04:45 (good, 1.75 h)	72.5° 07:45	6.46	40%	6.2°
2039-08-13 Sat	38	—	unknown	02:50–04:45 (good, 1.92 h)	72.5° 07:40	6.52	30%	15.0°
2039-08-14 Sun	45	—	unknown	02:40–04:45 (good, 2.08 h)	72.5° 07:35	6.58	22%	26.4°
2039-08-15 Mon	53	—	unknown	02:25–04:45 (good, 2.33 h)	72.5° 07:30	6.63	15%	38.1°
2039-08-16 Tue	61	—	unknown	02:20–04:50 (good, 2.5 h)	72.5° 07:30	6.69	9%	50.1°
2039-08-17 Wed	66	—	unknown	02:20–04:50 (good, 2.5 h)	72.5° 07:25	6.75	4%	62.3°
2039-08-18 Thu	68	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:20	6.81	1%	74.8°
2039-08-19 Fri	71	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:15	6.86	0%	87.5°
2039-08-20 Sat	74	—	unknown	02:05–04:55 (good, 2.83 h)	72.5° 07:10	6.92	1%	100.5°
2039-08-21 Sun	76	—	unknown	02:05–04:55 (good, 2.83 h)	72.5° 07:10	6.98	5%	113.7°
2039-08-22 Mon	80	—	unknown	02:00–05:00 (good, 3.0 h)	72.5° 07:05	7.04	11%	127.1°
2039-08-23 Tue	82	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 07:00	7.09	18%	140.6°
2039-08-24 Wed	84	—	unknown	01:50–05:00 (good, 3.17 h)	72.5° 06:55	7.15	28%	154.2°
2039-08-25 Thu	86	—	unknown	01:45–05:00 (good, 3.25 h)	72.5° 06:55	7.21	38%	167.4°
2039-08-26 Fri	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.5° 06:50	7.26	50%	173.6°
2039-08-27 Sat	91	—	unknown	01:40–05:05 (good, 3.42 h)	72.5° 06:45	7.32	61%	162.0°
2039-08-28 Sun	93	—	unknown	01:35–05:05 (good, 3.5 h)	72.5° 06:40	7.38	72%	148.2°
2039-08-29 Mon	95	—	unknown	01:35–05:10 (good, 3.58 h)	72.5° 06:35	7.43	82%	134.2°
2039-08-30 Tue	94	—	unknown	01:35–05:10 (good, 3.58 h)	72.5° 06:35	7.49	90%	120.0°
2039-08-31 Wed	88	—	unknown	01:40–05:10 (good, 3.5 h)	72.5° 06:30	7.55	95%	105.9°
2039-09-01 Thu	63	—	unknown	02:00–05:10 (good, 3.17 h)	72.5° 06:25	7.6	99%	92.0°
2039-09-02 Fri	49	—	unknown	03:20–05:15 (good, 1.92 h)	72.5° 06:20	7.66	100%	78.3°
2039-09-03 Sat	36	—	unknown	01:00–05:15 (marginal, 4.25 h)	72.5° 06:15	7.71	98%	64.9°
2039-09-04 Sun	26	—	unknown	01:05–05:15 (marginal, 4.17 h)	72.5° 06:15	7.77	95%	51.8°
2039-09-05 Mon	20	—	unknown	01:10–05:15 (marginal, 4.08 h)	72.5° 06:10	7.82	89%	39.1°
2039-09-06 Tue	19	—	unknown	01:00–05:20 (marginal, 4.33 h)	72.5° 06:05	7.88	82%	26.8°
2039-09-07 Wed	25	—	unknown	00:45–05:20 (marginal, 4.58 h)	72.5° 06:00	7.93	74%	15.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-08-09&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.