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.

2033-08-13astronomy score per night — click a bar for that night2033-09-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-08-13 Sat	16	—	unknown	02:25–04:45 (marginal, 2.33 h)	72.6° 07:40	6.54	86%	54.7°
2033-08-14 Sun	15	—	unknown	02:20–04:45 (marginal, 2.42 h)	72.6° 07:35	6.6	77%	40.3°
2033-08-15 Mon	18	—	unknown	02:10–04:50 (marginal, 2.67 h)	72.6° 07:30	6.66	66%	26.4°
2033-08-16 Tue	25	—	unknown	01:55–04:50 (marginal, 2.92 h)	72.6° 07:25	6.72	55%	13.6°
2033-08-17 Wed	34	—	unknown	02:40–04:50 (good, 2.17 h)	72.6° 07:20	6.78	44%	8.4°
2033-08-18 Thu	44	—	unknown	02:25–04:50 (good, 2.42 h)	72.6° 07:20	6.83	34%	18.1°
2033-08-19 Fri	56	—	unknown	02:10–04:55 (good, 2.75 h)	72.6° 07:15	6.89	24%	30.6°
2033-08-20 Sat	67	—	unknown	02:05–04:55 (good, 2.83 h)	72.6° 07:10	6.95	16%	43.3°
2033-08-21 Sun	74	—	unknown	02:00–04:55 (good, 2.92 h)	72.6° 07:05	7.0	9%	55.9°
2033-08-22 Mon	80	—	unknown	01:55–05:00 (good, 3.08 h)	72.6° 07:05	7.06	4%	68.4°
2033-08-23 Tue	83	—	unknown	01:55–05:00 (good, 3.08 h)	72.6° 07:00	7.12	1%	80.7°
2033-08-24 Wed	86	—	unknown	01:50–05:00 (good, 3.17 h)	72.6° 06:55	7.18	0%	92.8°
2033-08-25 Thu	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.6° 06:50	7.23	1%	104.8°
2033-08-26 Fri	90	—	unknown	01:40–05:05 (good, 3.42 h)	72.6° 06:45	7.29	4%	116.7°
2033-08-27 Sat	92	—	unknown	01:35–05:05 (good, 3.5 h)	72.6° 06:45	7.35	8%	128.4°
2033-08-28 Sun	95	—	unknown	01:35–05:05 (good, 3.5 h)	72.6° 06:40	7.4	14%	140.0°
2033-08-29 Mon	97	—	unknown	01:30–05:10 (good, 3.67 h)	72.6° 06:35	7.46	21%	151.4°
2033-08-30 Tue	98	—	unknown	01:25–05:10 (good, 3.75 h)	72.6° 06:30	7.52	30%	162.5°
2033-08-31 Wed	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.6° 06:25	7.57	39%	171.2°
2033-09-01 Thu	100	—	unknown	01:15–05:10 (good, 3.92 h)	72.6° 06:25	7.63	48%	168.3°
2033-09-02 Fri	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.6° 06:20	7.68	58%	157.6°
2033-09-03 Sat	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.6° 06:15	7.74	68%	145.3°
2033-09-04 Sun	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.6° 06:10	7.79	78%	132.3°
2033-09-05 Mon	100	—	unknown	01:10–05:20 (good, 4.17 h)	72.6° 06:10	7.85	86%	118.8°
2033-09-06 Tue	100	—	unknown	01:15–05:20 (good, 4.08 h)	72.6° 06:05	7.9	93%	104.8°
2033-09-07 Wed	70	—	unknown	01:50–05:20 (good, 3.5 h)	72.6° 06:00	7.96	98%	90.3°
2033-09-08 Thu	51	—	unknown	03:25–05:20 (good, 1.92 h)	72.6° 05:55	8.01	100%	75.5°
2033-09-09 Fri	35	—	unknown	00:45–05:25 (marginal, 4.67 h)	72.6° 05:50	8.07	99%	60.6°
2033-09-10 Sat	24	—	unknown	00:50–05:25 (marginal, 4.58 h)	72.6° 05:50	8.12	95%	45.7°
2033-09-11 Sun	17	—	unknown	00:50–05:25 (marginal, 4.58 h)	72.6° 05:45	8.18	88%	31.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-08-13&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.