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: 09-08 (100), 09-09 (100), 09-10 (100), 09-11 (100), 09-12 (100) — by astronomy; check the weather when the night is within four days.

2045-08-20astronomy score per night — click a bar for that night2045-09-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-08-20 Sun	75	—	unknown	02:05–04:55 (good, 2.83 h)	72.6° 07:10	6.95	64%	164.6°
2045-08-21 Mon	77	—	unknown	02:00–04:55 (good, 2.92 h)	72.6° 07:05	7.01	74%	152.4°
2045-08-22 Tue	80	—	unknown	02:05–05:00 (good, 2.92 h)	72.6° 07:05	7.07	82%	140.3°
2045-08-23 Wed	80	—	unknown	02:00–05:00 (good, 3.0 h)	72.6° 07:00	7.13	88%	128.3°
2045-08-24 Thu	80	—	unknown	02:00–05:00 (good, 3.0 h)	72.6° 06:55	7.18	94%	116.5°
2045-08-25 Fri	64	—	unknown	02:05–05:05 (good, 3.0 h)	72.6° 06:50	7.24	98%	104.6°
2045-08-26 Sat	53	—	unknown	02:25–05:05 (good, 2.67 h)	72.6° 06:45	7.3	100%	92.8°
2045-08-27 Sun	42	—	unknown	03:35–05:05 (good, 1.5 h)	72.6° 06:45	7.35	100%	80.9°
2045-08-28 Mon	33	—	unknown	05:00–05:05 (good, 0.08 h)	72.6° 06:40	7.41	98%	69.0°
2045-08-29 Tue	25	—	unknown	01:30–05:10 (marginal, 3.67 h)	72.6° 06:35	7.47	95%	56.9°
2045-08-30 Wed	19	—	unknown	01:35–05:10 (marginal, 3.58 h)	72.6° 06:30	7.52	90%	44.8°
2045-08-31 Thu	16	—	unknown	01:30–05:10 (marginal, 3.67 h)	72.6° 06:25	7.58	83%	32.4°
2045-09-01 Fri	20	—	unknown	01:15–05:15 (marginal, 4.0 h)	72.6° 06:25	7.63	75%	19.9°
2045-09-02 Sat	28	—	unknown	01:00–05:15 (marginal, 4.25 h)	72.6° 06:20	7.69	66%	7.2°
2045-09-03 Sun	40	—	unknown	00:45–05:15 (marginal, 4.5 h)	72.6° 06:15	7.74	55%	6.1°
2045-09-04 Mon	55	—	unknown	01:30–05:15 (good, 3.75 h)	72.6° 06:10	7.8	44%	19.4°
2045-09-05 Tue	74	—	unknown	01:15–05:20 (good, 4.08 h)	72.6° 06:10	7.86	34%	33.2°
2045-09-06 Wed	89	—	unknown	01:00–05:20 (good, 4.33 h)	72.6° 06:05	7.91	23%	47.4°
2045-09-07 Thu	95	—	unknown	00:55–05:20 (good, 4.42 h)	72.6° 06:00	7.96	14%	62.0°
2045-09-08 Fri	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.6° 05:55	8.02	7%	76.9°
2045-09-09 Sat	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.6° 05:50	8.07	2%	92.0°
2045-09-10 Sun	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.6° 05:50	8.13	0%	107.1°
2045-09-11 Mon	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.6° 05:45	8.18	1%	122.1°
2045-09-12 Tue	100	—	unknown	00:35–05:25 (good, 4.83 h)	72.6° 05:40	8.23	5%	136.8°
2045-09-13 Wed	100	—	unknown	00:30–05:30 (good, 5.0 h)	72.6° 05:35	8.29	11%	151.1°
2045-09-14 Thu	100	—	unknown	00:25–05:30 (good, 5.08 h)	72.6° 05:30	8.34	20%	165.0°
2045-09-15 Fri	100	—	unknown	00:20–05:30 (good, 5.17 h)	72.6° 05:30	8.39	29%	178.1°
2045-09-16 Sat	100	—	unknown	00:20–05:30 (good, 5.17 h)	72.6° 05:25	8.45	39%	168.5°
2045-09-17 Sun	100	—	unknown	00:15–05:35 (good, 5.33 h)	72.6° 05:20	8.5	49%	156.0°
2045-09-18 Mon	100	—	unknown	00:10–05:35 (good, 5.42 h)	72.6° 05:15	8.55	58%	143.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-08-20&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.