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), 08-30 (99) — by astronomy; check the weather when the night is within four days.

2044-08-12astronomy score per night — click a bar for that night2044-09-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-08-12 Fri	15	—	unknown	02:30–04:45 (marginal, 2.25 h)	72.6° 07:40	6.51	84%	52.2°
2044-08-13 Sat	14	—	unknown	02:25–04:45 (marginal, 2.33 h)	72.6° 07:35	6.56	76%	39.1°
2044-08-14 Sun	16	—	unknown	02:15–04:45 (marginal, 2.5 h)	72.6° 07:35	6.62	66%	25.8°
2044-08-15 Mon	23	—	unknown	02:00–04:50 (marginal, 2.83 h)	72.6° 07:30	6.68	55%	12.3°
2044-08-16 Tue	32	—	unknown	03:05–04:50 (good, 1.75 h)	72.6° 07:25	6.74	44%	2.0°
2044-08-17 Wed	42	—	unknown	02:30–04:50 (good, 2.33 h)	72.6° 07:20	6.79	33%	15.8°
2044-08-18 Thu	54	—	unknown	02:20–04:55 (good, 2.58 h)	72.5° 07:15	6.85	22%	30.2°
2044-08-19 Fri	66	—	unknown	02:10–04:55 (good, 2.75 h)	72.6° 07:15	6.91	13%	44.9°
2044-08-20 Sat	74	—	unknown	02:05–04:55 (good, 2.83 h)	72.6° 07:10	6.97	6%	59.6°
2044-08-21 Sun	78	—	unknown	02:00–04:55 (good, 2.92 h)	72.6° 07:05	7.02	2%	74.4°
2044-08-22 Mon	81	—	unknown	01:55–05:00 (good, 3.08 h)	72.6° 07:00	7.08	0%	89.1°
2044-08-23 Tue	84	—	unknown	01:50–05:00 (good, 3.17 h)	72.6° 07:00	7.14	1%	103.5°
2044-08-24 Wed	86	—	unknown	01:50–05:00 (good, 3.17 h)	72.6° 06:55	7.2	5%	117.7°
2044-08-25 Thu	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.6° 06:50	7.25	10%	131.4°
2044-08-26 Fri	90	—	unknown	01:40–05:05 (good, 3.42 h)	72.6° 06:45	7.31	18%	144.7°
2044-08-27 Sat	92	—	unknown	01:35–05:05 (good, 3.5 h)	72.6° 06:40	7.37	27%	157.6°
2044-08-28 Sun	95	—	unknown	01:30–05:05 (good, 3.58 h)	72.6° 06:40	7.42	36%	170.1°
2044-08-29 Mon	98	—	unknown	01:30–05:10 (good, 3.67 h)	72.6° 06:35	7.48	46%	177.4°
2044-08-30 Tue	99	—	unknown	01:25–05:10 (good, 3.75 h)	72.6° 06:30	7.54	55%	165.6°
2044-08-31 Wed	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.6° 06:25	7.59	64%	153.7°
2044-09-01 Thu	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.5° 06:20	7.65	73%	141.9°
2044-09-02 Fri	100	—	unknown	01:20–05:15 (good, 3.92 h)	72.6° 06:20	7.7	81%	130.0°
2044-09-03 Sat	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.6° 06:15	7.76	88%	118.1°
2044-09-04 Sun	98	—	unknown	01:20–05:15 (good, 3.92 h)	72.6° 06:10	7.81	94%	106.0°
2044-09-05 Mon	73	—	unknown	01:35–05:20 (good, 3.75 h)	72.6° 06:05	7.87	98%	93.7°
2044-09-06 Tue	57	—	unknown	02:50–05:20 (good, 2.5 h)	72.6° 06:05	7.92	100%	81.2°
2044-09-07 Wed	42	—	unknown	04:30–05:20 (good, 0.83 h)	72.6° 06:00	7.98	100%	68.5°
2044-09-08 Thu	30	—	unknown	00:50–05:20 (marginal, 4.5 h)	72.6° 05:55	8.03	98%	55.5°
2044-09-09 Fri	21	—	unknown	01:00–05:25 (marginal, 4.42 h)	72.6° 05:50	8.09	94%	42.3°
2044-09-10 Sat	16	—	unknown	01:00–05:25 (marginal, 4.42 h)	72.6° 05:45	8.14	87%	29.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-08-12&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.