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: 08-12 (52), 08-10 (50), 08-11 (50), 08-09 (48), 08-08 (45) — by astronomy; check the weather when the night is within four days.

2038-07-21astronomy score per night — click a bar for that night2038-08-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-07-21 Wed	4	—	unknown	03:45–04:10 (marginal, 0.42 h)	72.5° 09:10	5.28	71%	56.5°
2038-07-22 Thu	5	—	unknown	03:40–04:10 (marginal, 0.5 h)	72.5° 09:05	5.33	62%	44.7°
2038-07-23 Fri	6	—	unknown	03:35–04:10 (marginal, 0.58 h)	72.5° 09:00	5.38	53%	33.1°
2038-07-24 Sat	9	—	unknown	03:25–04:15 (marginal, 0.83 h)	72.5° 09:00	5.43	43%	21.8°
2038-07-25 Sun	12	—	unknown	04:10–04:15 (good, 0.08 h)	72.5° 08:55	5.48	34%	11.4°
2038-07-26 Mon	15	—	unknown	03:55–04:15 (good, 0.33 h)	72.5° 08:50	5.53	25%	8.3°
2038-07-27 Tue	19	—	unknown	03:45–04:20 (good, 0.58 h)	72.5° 08:45	5.58	17%	17.3°
2038-07-28 Wed	22	—	unknown	03:40–04:20 (good, 0.67 h)	72.5° 08:40	5.64	10%	29.1°
2038-07-29 Thu	25	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:40	5.69	5%	41.6°
2038-07-30 Fri	27	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:35	5.74	1%	54.5°
2038-07-31 Sat	29	—	unknown	03:25–04:25 (good, 1.0 h)	72.5° 08:30	5.8	0%	67.8°
2038-08-01 Sun	31	—	unknown	03:20–04:25 (good, 1.08 h)	72.5° 08:25	5.85	1%	81.4°
2038-08-02 Mon	33	—	unknown	03:15–04:25 (good, 1.17 h)	72.5° 08:20	5.91	5%	95.3°
2038-08-03 Tue	35	—	unknown	03:10–04:30 (good, 1.33 h)	72.5° 08:20	5.96	11%	109.3°
2038-08-04 Wed	37	—	unknown	03:10–04:30 (good, 1.33 h)	72.5° 08:15	6.02	19%	123.4°
2038-08-05 Thu	39	—	unknown	03:05–04:30 (good, 1.42 h)	72.5° 08:10	6.08	29%	137.4°
2038-08-06 Fri	41	—	unknown	03:00–04:35 (good, 1.58 h)	72.5° 08:05	6.13	40%	151.3°
2038-08-07 Sat	43	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:00	6.19	51%	164.5°
2038-08-08 Sun	45	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:00	6.25	62%	172.5°
2038-08-09 Mon	48	—	unknown	02:50–04:40 (good, 1.83 h)	72.5° 07:55	6.3	73%	163.7°
2038-08-10 Tue	50	—	unknown	02:45–04:40 (good, 1.92 h)	72.5° 07:50	6.36	82%	150.8°
2038-08-11 Wed	50	—	unknown	02:50–04:40 (good, 1.83 h)	72.5° 07:45	6.42	90%	137.4°
2038-08-12 Thu	52	—	unknown	02:45–04:45 (good, 2.0 h)	72.5° 07:45	6.47	95%	124.1°
2038-08-13 Fri	43	—	unknown	02:45–04:45 (good, 2.0 h)	72.5° 07:40	6.53	99%	110.9°
2038-08-14 Sat	37	—	unknown	02:55–04:45 (good, 1.83 h)	72.5° 07:35	6.59	100%	98.0°
2038-08-15 Sun	31	—	unknown	03:45–04:50 (good, 1.08 h)	72.5° 07:30	6.65	99%	85.3°
2038-08-16 Mon	25	—	unknown	02:05–05:30 (marginal, 3.42 h)	72.5° 07:25	6.7	96%	72.8°
2038-08-17 Tue	21	—	unknown	02:05–04:50 (marginal, 2.75 h)	72.5° 07:25	6.76	91%	60.6°
2038-08-18 Wed	18	—	unknown	02:05–04:50 (marginal, 2.75 h)	72.5° 07:20	6.82	85%	48.7°
2038-08-19 Thu	17	—	unknown	02:00–04:55 (marginal, 2.92 h)	72.5° 07:15	6.88	77%	36.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-07-21&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.