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: 08-17 (66), 08-16 (64), 08-15 (60), 08-14 (55), 08-13 (50) — by astronomy; check the weather when the night is within four days.

2031-07-19astronomy score per night — click a bar for that night2031-08-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-07-19 Sat	7	—	unknown	04:10–04:50 (marginal, 0.67 h)	72.5° 09:20	5.17	0%	61.8°
2031-07-20 Sun	8	—	unknown	04:10–04:55 (marginal, 0.75 h)	72.5° 09:15	5.21	2%	73.7°
2031-07-21 Mon	11	—	unknown	04:05–04:10 (good, 0.08 h)	72.5° 09:10	5.26	5%	85.6°
2031-07-22 Tue	11	—	unknown	04:00–04:10 (good, 0.17 h)	72.5° 09:05	5.31	10%	97.7°
2031-07-23 Wed	13	—	unknown	03:55–04:10 (good, 0.25 h)	72.5° 09:00	5.36	17%	109.9°
2031-07-24 Thu	16	—	unknown	03:50–04:15 (good, 0.42 h)	72.5° 09:00	5.41	25%	122.3°
2031-07-25 Fri	18	—	unknown	03:50–04:15 (good, 0.42 h)	72.5° 08:55	5.46	34%	134.9°
2031-07-26 Sat	20	—	unknown	03:45–04:15 (good, 0.5 h)	72.5° 08:50	5.51	45%	147.8°
2031-07-27 Sun	21	—	unknown	03:40–04:15 (good, 0.58 h)	72.5° 08:45	5.57	55%	160.9°
2031-07-28 Mon	24	—	unknown	03:35–04:20 (good, 0.75 h)	72.5° 08:45	5.62	66%	173.4°
2031-07-29 Tue	25	—	unknown	03:35–04:20 (good, 0.75 h)	72.5° 08:40	5.67	77%	169.6°
2031-07-30 Wed	27	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:35	5.73	86%	155.6°
2031-07-31 Thu	27	—	unknown	03:30–04:25 (good, 0.92 h)	72.5° 08:30	5.78	93%	140.9°
2031-08-01 Fri	25	—	unknown	03:30–04:25 (good, 0.92 h)	72.5° 08:25	5.84	98%	125.9°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-07-19&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.