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: 08-27 (91), 08-28 (91), 08-29 (90), 08-26 (89), 08-25 (87) — by astronomy; check the weather when the night is within four days.

2031-08-02astronomy score per night — click a bar for that night2031-08-31

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-08-02 Sat	23	—	unknown	03:35–04:25 (good, 0.83 h)	72.5° 08:25	5.89	100%	110.8°
2031-08-03 Sun	20	—	unknown	03:45–04:30 (good, 0.75 h)	72.5° 08:20	5.95	99%	95.8°
2031-08-04 Mon	16	—	unknown	02:50–04:30 (marginal, 1.67 h)	72.5° 08:15	6.0	95%	81.0°
2031-08-05 Tue	13	—	unknown	02:55–04:30 (marginal, 1.58 h)	72.5° 08:10	6.06	88%	66.6°
2031-08-06 Wed	12	—	unknown	02:55–04:35 (marginal, 1.67 h)	72.5° 08:05	6.12	80%	52.6°
2031-08-07 Thu	12	—	unknown	02:50–04:35 (marginal, 1.75 h)	72.5° 08:05	6.17	71%	39.2°
2031-08-08 Fri	14	—	unknown	02:40–04:35 (marginal, 1.92 h)	72.5° 08:00	6.23	61%	26.3°
2031-08-09 Sat	21	—	unknown	02:25–04:40 (marginal, 2.25 h)	72.5° 07:55	6.29	51%	14.0°
2031-08-10 Sun	27	—	unknown	03:10–04:40 (good, 1.5 h)	72.5° 07:50	6.34	41%	4.7°
2031-08-11 Mon	34	—	unknown	02:55–04:40 (good, 1.75 h)	72.5° 07:50	6.4	32%	12.1°
2031-08-12 Tue	42	—	unknown	02:45–04:45 (good, 2.0 h)	72.5° 07:45	6.46	23%	23.6°
2031-08-13 Wed	50	—	unknown	02:35–04:45 (good, 2.17 h)	72.5° 07:40	6.52	16%	35.3°
2031-08-14 Thu	55	—	unknown	02:30–04:45 (good, 2.25 h)	72.5° 07:35	6.57	10%	47.0°
2031-08-15 Fri	60	—	unknown	02:25–04:45 (good, 2.33 h)	72.5° 07:30	6.63	5%	58.8°
2031-08-16 Sat	64	—	unknown	02:20–04:50 (good, 2.5 h)	72.5° 07:30	6.69	2%	70.7°
2031-08-17 Sun	66	—	unknown	02:20–04:50 (good, 2.5 h)	72.5° 07:25	6.75	0%	82.6°
2031-08-18 Mon	68	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:20	6.8	1%	94.7°
2031-08-19 Tue	71	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:15	6.86	3%	107.0°
2031-08-20 Wed	74	—	unknown	02:05–04:55 (good, 2.83 h)	72.5° 07:10	6.92	7%	119.4°
2031-08-21 Thu	76	—	unknown	02:00–04:55 (good, 2.92 h)	72.5° 07:10	6.98	14%	132.0°
2031-08-22 Fri	80	—	unknown	02:00–05:00 (good, 3.0 h)	72.5° 07:05	7.03	21%	144.7°
2031-08-23 Sat	82	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 07:00	7.09	30%	157.7°
2031-08-24 Sun	84	—	unknown	01:50–05:00 (good, 3.17 h)	72.5° 06:55	7.15	41%	170.3°
2031-08-25 Mon	87	—	unknown	01:45–05:00 (good, 3.25 h)	72.5° 06:50	7.2	52%	173.0°
2031-08-26 Tue	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.5° 06:50	7.26	63%	160.2°
2031-08-27 Wed	91	—	unknown	01:45–05:05 (good, 3.33 h)	72.5° 06:45	7.32	74%	146.2°
2031-08-28 Thu	91	—	unknown	01:40–05:05 (good, 3.42 h)	72.5° 06:40	7.37	83%	131.7°
2031-08-29 Fri	90	—	unknown	01:40–05:10 (good, 3.5 h)	72.5° 06:35	7.43	91%	117.0°
2031-08-30 Sat	69	—	unknown	01:50–05:10 (good, 3.33 h)	72.5° 06:35	7.49	97%	102.2°
2031-08-31 Sun	53	—	unknown	02:45–05:10 (good, 2.42 h)	72.5° 06:30	7.54	100%	87.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-08-02&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.