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: 08-22 (76), 08-20 (75), 08-21 (75), 08-19 (73), 08-18 (70) — by astronomy; check the weather when the night is within four days.

2037-08-02astronomy score per night — click a bar for that night2037-08-31

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-08-02 Sun	12	—	unknown	03:00–04:30 (marginal, 1.5 h)	72.5° 08:20	5.92	63%	35.6°
2037-08-03 Mon	15	—	unknown	02:50–04:30 (marginal, 1.67 h)	72.5° 08:15	5.98	54%	24.1°
2037-08-04 Tue	20	—	unknown	03:45–04:30 (good, 0.75 h)	72.5° 08:15	6.03	44%	13.4°
2037-08-05 Wed	25	—	unknown	03:20–04:30 (good, 1.17 h)	72.5° 08:10	6.09	34%	8.9°
2037-08-06 Thu	32	—	unknown	03:10–04:35 (good, 1.42 h)	72.5° 08:05	6.15	25%	17.5°
2037-08-07 Fri	37	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:00	6.2	16%	29.8°
2037-08-08 Sat	43	—	unknown	02:50–04:35 (good, 1.75 h)	72.5° 08:00	6.26	9%	43.3°
2037-08-09 Sun	49	—	unknown	02:50–04:40 (good, 1.83 h)	72.5° 07:55	6.32	3%	57.3°
2037-08-10 Mon	51	—	unknown	02:45–04:40 (good, 1.92 h)	72.5° 07:50	6.37	0%	71.7°
2037-08-11 Tue	53	—	unknown	02:40–04:40 (good, 2.0 h)	72.5° 07:45	6.43	0%	86.5°
2037-08-12 Wed	56	—	unknown	02:35–04:45 (good, 2.17 h)	72.5° 07:40	6.49	3%	101.4°
2037-08-13 Thu	57	—	unknown	02:30–04:45 (good, 2.25 h)	72.5° 07:40	6.55	9%	116.2°
2037-08-14 Fri	59	—	unknown	02:30–04:45 (good, 2.25 h)	72.5° 07:35	6.6	17%	130.7°
2037-08-15 Sat	63	—	unknown	02:25–04:50 (good, 2.42 h)	72.5° 07:30	6.66	27%	144.9°
2037-08-16 Sun	65	—	unknown	02:20–04:50 (good, 2.5 h)	72.5° 07:25	6.72	38%	158.3°
2037-08-17 Mon	67	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:20	6.78	49%	169.4°
2037-08-18 Tue	70	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:20	6.83	60%	168.7°
2037-08-19 Wed	73	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:15	6.89	70%	157.9°
2037-08-20 Thu	75	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:10	6.95	79%	145.8°
2037-08-21 Fri	75	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:05	7.01	86%	133.5°
2037-08-22 Sat	76	—	unknown	02:05–05:00 (good, 2.92 h)	72.5° 07:00	7.06	92%	121.3°
2037-08-23 Sun	64	—	unknown	02:10–05:00 (good, 2.83 h)	72.5° 07:00	7.12	97%	109.3°
2037-08-24 Mon	55	—	unknown	02:15–05:00 (good, 2.75 h)	72.5° 06:55	7.18	99%	97.3°
2037-08-25 Tue	46	—	unknown	03:05–05:05 (good, 2.0 h)	72.5° 06:50	7.24	100%	85.5°
2037-08-26 Wed	36	—	unknown	04:15–05:05 (good, 0.83 h)	72.5° 06:45	7.29	99%	73.7°
2037-08-27 Thu	28	—	unknown	01:30–05:05 (marginal, 3.58 h)	72.5° 06:45	7.35	96%	62.0°
2037-08-28 Fri	23	—	unknown	01:30–05:05 (marginal, 3.58 h)	72.5° 06:40	7.41	91%	50.4°
2037-08-29 Sat	20	—	unknown	01:30–05:10 (marginal, 3.67 h)	72.5° 06:35	7.46	85%	38.8°
2037-08-30 Sun	20	—	unknown	01:20–05:10 (marginal, 3.83 h)	72.5° 06:30	7.52	78%	27.4°
2037-08-31 Mon	26	—	unknown	01:05–05:10 (marginal, 4.08 h)	72.5° 06:25	7.57	69%	16.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-08-02&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.