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: 08-20 (73), 08-19 (72), 08-21 (70), 08-18 (69), 08-17 (67) — by astronomy; check the weather when the night is within four days.

2029-07-27astronomy score per night — click a bar for that night2029-08-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-07-27 Fri	11	—	unknown	03:15–04:20 (marginal, 1.08 h)	72.5° 08:45	5.59	94%	86.0°
2029-07-28 Sat	10	—	unknown	03:20–04:20 (marginal, 1.0 h)	72.5° 08:40	5.65	88%	73.5°
2029-07-29 Sun	9	—	unknown	03:20–04:20 (marginal, 1.0 h)	72.5° 08:35	5.7	81%	61.3°
2029-07-30 Mon	9	—	unknown	03:15–04:25 (marginal, 1.17 h)	72.5° 08:35	5.75	73%	49.3°
2029-07-31 Tue	10	—	unknown	03:10–04:25 (marginal, 1.25 h)	72.5° 08:30	5.81	64%	37.4°
2029-08-01 Wed	12	—	unknown	03:00–04:25 (marginal, 1.42 h)	72.5° 08:25	5.86	55%	25.6°
2029-08-02 Thu	16	—	unknown	02:50–04:30 (marginal, 1.67 h)	72.5° 08:20	5.92	46%	13.7°
2029-08-03 Fri	21	—	unknown	03:35–04:30 (good, 0.92 h)	72.5° 08:15	5.97	36%	2.0°
2029-08-04 Sat	27	—	unknown	03:20–04:30 (good, 1.17 h)	72.5° 08:15	6.03	27%	10.6°
2029-08-05 Sun	32	—	unknown	03:10–04:30 (good, 1.33 h)	72.5° 08:10	6.09	19%	23.0°
2029-08-06 Mon	39	—	unknown	03:00–04:35 (good, 1.58 h)	72.5° 08:05	6.14	11%	35.8°
2029-08-07 Tue	43	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:00	6.2	6%	48.9°
2029-08-08 Wed	46	—	unknown	02:50–04:35 (good, 1.75 h)	72.5° 07:55	6.26	2%	62.4°
2029-08-09 Thu	49	—	unknown	02:50–04:40 (good, 1.83 h)	72.5° 07:55	6.31	0%	76.3°
2029-08-10 Fri	51	—	unknown	02:45–04:40 (good, 1.92 h)	72.5° 07:50	6.37	1%	90.4°
2029-08-11 Sat	53	—	unknown	02:40–04:40 (good, 2.0 h)	72.5° 07:45	6.43	5%	104.7°
2029-08-12 Sun	56	—	unknown	02:35–04:45 (good, 2.17 h)	72.5° 07:40	6.49	11%	119.2°
2029-08-13 Mon	58	—	unknown	02:30–04:45 (good, 2.25 h)	72.5° 07:40	6.54	19%	133.7°
2029-08-14 Tue	59	—	unknown	02:30–04:45 (good, 2.25 h)	72.5° 07:35	6.6	29%	148.1°
2029-08-15 Wed	63	—	unknown	02:25–04:50 (good, 2.42 h)	72.5° 07:30	6.66	40%	162.4°
2029-08-16 Thu	65	—	unknown	02:20–04:50 (good, 2.5 h)	72.5° 07:25	6.72	52%	176.4°
2029-08-17 Fri	67	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:20	6.77	63%	169.4°
2029-08-18 Sat	69	—	unknown	02:10–04:50 (good, 2.67 h)	72.5° 07:20	6.83	73%	155.7°
2029-08-19 Sun	72	—	unknown	02:15–04:55 (good, 2.67 h)	72.5° 07:15	6.89	82%	142.2°
2029-08-20 Mon	73	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:10	6.95	90%	128.8°
2029-08-21 Tue	70	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:05	7.0	95%	115.7°
2029-08-22 Wed	55	—	unknown	02:20–05:00 (good, 2.67 h)	72.5° 07:00	7.06	98%	102.8°
2029-08-23 Thu	45	—	unknown	03:00–05:00 (good, 2.0 h)	72.5° 07:00	7.12	100%	90.1°
2029-08-24 Fri	36	—	unknown	04:10–05:00 (good, 0.83 h)	72.5° 06:55	7.17	99%	77.6°
2029-08-25 Sat	28	—	unknown	01:40–05:05 (marginal, 3.42 h)	72.5° 06:50	7.23	96%	65.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-07-27&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.