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.

2046-08-22astronomy score per night — click a bar for that night2046-09-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-08-22 Wed	20	—	unknown	01:50–05:00 (marginal, 3.17 h)	72.6° 07:05	7.05	68%	20.5°
2046-08-23 Thu	27	—	unknown	01:35–05:00 (marginal, 3.42 h)	72.6° 07:00	7.11	58%	8.4°
2046-08-24 Fri	38	—	unknown	03:15–05:00 (good, 1.75 h)	72.6° 06:55	7.17	48%	4.0°
2046-08-25 Sat	49	—	unknown	02:05–05:05 (good, 3.0 h)	72.6° 06:50	7.23	38%	16.6°
2046-08-26 Sun	62	—	unknown	01:55–05:05 (good, 3.17 h)	72.6° 06:50	7.28	28%	29.7°
2046-08-27 Mon	77	—	unknown	01:40–05:05 (good, 3.42 h)	72.6° 06:45	7.34	19%	43.2°
2046-08-28 Tue	89	—	unknown	01:35–05:05 (good, 3.5 h)	72.6° 06:40	7.4	11%	57.1°
2046-08-29 Wed	96	—	unknown	01:30–05:10 (good, 3.67 h)	72.6° 06:35	7.45	5%	71.6°
2046-08-30 Thu	98	—	unknown	01:25–05:10 (good, 3.75 h)	72.6° 06:30	7.51	1%	86.4°
2046-08-31 Fri	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.6° 06:30	7.56	0%	101.4°
2046-09-01 Sat	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.6° 06:25	7.62	2%	116.6°
2046-09-02 Sun	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.6° 06:20	7.68	7%	131.7°
2046-09-03 Mon	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.6° 06:15	7.73	15%	146.6°
2046-09-04 Tue	100	—	unknown	01:05–05:15 (good, 4.17 h)	72.6° 06:15	7.79	24%	161.1°
2046-09-05 Wed	100	—	unknown	01:05–05:20 (good, 4.25 h)	72.6° 06:10	7.84	34%	175.3°
2046-09-06 Thu	100	—	unknown	01:00–05:20 (good, 4.33 h)	72.6° 06:05	7.9	45%	170.9°
2046-09-07 Fri	100	—	unknown	00:55–05:20 (good, 4.42 h)	72.6° 06:00	7.95	56%	157.5°
2046-09-08 Sat	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.6° 05:55	8.01	66%	144.5°
2046-09-09 Sun	100	—	unknown	00:55–05:25 (good, 4.5 h)	72.6° 05:55	8.06	75%	131.8°
2046-09-10 Mon	100	—	unknown	00:50–05:25 (good, 4.58 h)	72.6° 05:50	8.11	83%	119.4°
2046-09-11 Tue	100	—	unknown	00:55–05:25 (good, 4.5 h)	72.6° 05:45	8.17	90%	107.1°
2046-09-12 Wed	100	—	unknown	01:00–05:25 (good, 4.42 h)	72.6° 05:40	8.22	95%	95.0°
2046-09-13 Thu	70	—	unknown	02:10–05:30 (good, 3.33 h)	72.6° 05:35	8.27	98%	83.0°
2046-09-14 Fri	53	—	unknown	03:35–05:30 (good, 1.92 h)	72.6° 05:35	8.33	100%	71.1°
2046-09-15 Sat	38	—	unknown	00:25–05:30 (marginal, 5.08 h)	72.6° 05:30	8.38	100%	59.3°
2046-09-16 Sun	27	—	unknown	00:35–05:30 (marginal, 4.92 h)	72.6° 05:25	8.43	97%	47.4°
2046-09-17 Mon	18	—	unknown	01:30–05:35 (marginal, 4.08 h)	72.6° 05:20	8.49	94%	35.6°
2046-09-18 Tue	17	—	unknown	00:30–05:35 (marginal, 5.08 h)	72.6° 05:20	8.54	88%	23.7°
2046-09-19 Wed	22	—	unknown	00:10–05:35 (marginal, 5.42 h)	72.6° 05:15	8.59	82%	11.7°
2046-09-20 Thu	31	—	unknown	23:50–05:35 (marginal, 5.75 h)	72.6° 05:10	8.64	73%	0.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-08-22&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.