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: 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100), 09-05 (100) — by astronomy; check the weather when the night is within four days.

2043-08-14astronomy score per night — click a bar for that night2043-09-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-08-14 Fri	58	—	unknown	02:30–04:45 (good, 2.25 h)	72.6° 07:35	6.58	70%	164.3°
2043-08-15 Sat	60	—	unknown	02:25–04:45 (good, 2.33 h)	72.5° 07:30	6.64	78%	152.3°
2043-08-16 Sun	64	—	unknown	02:30–04:50 (good, 2.33 h)	72.5° 07:30	6.69	86%	140.0°
2043-08-17 Mon	64	—	unknown	02:25–04:50 (good, 2.42 h)	72.6° 07:25	6.75	92%	127.6°
2043-08-18 Tue	62	—	unknown	02:25–04:50 (good, 2.42 h)	72.6° 07:20	6.81	97%	114.8°
2043-08-19 Wed	48	—	unknown	02:30–04:55 (good, 2.42 h)	72.6° 07:15	6.87	99%	101.7°
2043-08-20 Thu	39	—	unknown	03:10–04:55 (good, 1.75 h)	72.5° 07:10	6.92	100%	88.3°
2043-08-21 Fri	30	—	unknown	04:30–04:55 (good, 0.42 h)	72.6° 07:10	6.98	98%	74.7°
2043-08-22 Sat	23	—	unknown	01:50–05:00 (marginal, 3.17 h)	72.6° 07:05	7.04	94%	60.8°
2043-08-23 Sun	18	—	unknown	01:55–05:00 (marginal, 3.08 h)	72.6° 07:00	7.1	87%	46.8°
2043-08-24 Mon	16	—	unknown	01:50–05:00 (marginal, 3.17 h)	72.5° 06:55	7.15	78%	32.7°
2043-08-25 Tue	21	—	unknown	01:35–05:00 (marginal, 3.42 h)	72.5° 06:55	7.21	68%	18.5°
2043-08-26 Wed	31	—	unknown	01:20–05:05 (marginal, 3.75 h)	72.6° 06:50	7.27	57%	4.3°
2043-08-27 Thu	43	—	unknown	02:10–05:05 (good, 2.92 h)	72.6° 06:45	7.32	46%	9.9°
2043-08-28 Fri	57	—	unknown	01:50–05:05 (good, 3.25 h)	72.6° 06:40	7.38	34%	24.0°
2043-08-29 Sat	74	—	unknown	01:30–05:10 (good, 3.67 h)	72.5° 06:35	7.44	24%	38.0°
2043-08-30 Sun	88	—	unknown	01:25–05:10 (good, 3.75 h)	72.5° 06:35	7.49	15%	52.0°
2043-08-31 Mon	96	—	unknown	01:25–05:10 (good, 3.75 h)	72.6° 06:30	7.55	8%	65.8°
2043-09-01 Tue	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.6° 06:25	7.6	3%	79.4°
2043-09-02 Wed	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.6° 06:20	7.66	0%	92.8°
2043-09-03 Thu	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.5° 06:15	7.72	0%	106.0°
2043-09-04 Fri	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.6° 06:15	7.77	2%	118.9°
2043-09-05 Sat	100	—	unknown	01:05–05:15 (good, 4.17 h)	72.6° 06:10	7.83	6%	131.5°
2043-09-06 Sun	100	—	unknown	01:00–05:20 (good, 4.33 h)	72.6° 06:05	7.88	11%	143.8°
2043-09-07 Mon	100	—	unknown	00:55–05:20 (good, 4.42 h)	72.5° 06:00	7.94	18%	156.0°
2043-09-08 Tue	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.5° 06:00	7.99	26%	167.9°
2043-09-09 Wed	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.6° 05:55	8.05	35%	179.5°
2043-09-10 Thu	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.6° 05:50	8.1	44%	168.4°
2043-09-11 Fri	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.6° 05:45	8.15	54%	156.5°
2043-09-12 Sat	100	—	unknown	00:35–05:25 (good, 4.83 h)	72.5° 05:40	8.21	63%	144.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-08-14&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.