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: 07-18 (5), 07-17 (3), 07-15 (2), 07-16 (2), 07-09 (1) — by astronomy; check the weather when the night is within four days.

2047-06-19astronomy score per night — click a bar for that night2047-07-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-06-19 Wed	0	—	unknown	—	72.6° 11:15	4.42	12%	10.6°
2047-06-20 Thu	0	—	unknown	—	72.6° 11:10	4.42	6%	1.5°
2047-06-21 Fri	0	—	unknown	—	72.6° 11:10	4.42	2%	13.6°
2047-06-22 Sat	0	—	unknown	—	72.6° 11:05	4.42	0%	25.9°
2047-06-23 Sun	0	—	unknown	—	72.6° 11:00	4.43	0%	38.4°
2047-06-24 Mon	0	—	unknown	—	72.6° 10:55	4.44	2%	51.2°
2047-06-25 Tue	0	—	unknown	—	72.6° 10:55	4.44	6%	64.1°
2047-06-26 Wed	0	—	unknown	—	72.6° 10:50	4.45	13%	77.3°
2047-06-27 Thu	0	—	unknown	—	72.6° 10:45	4.47	21%	90.7°
2047-06-28 Fri	0	—	unknown	—	72.6° 10:40	4.48	30%	104.3°
2047-06-29 Sat	0	—	unknown	—	72.6° 10:35	4.5	41%	118.1°
2047-06-30 Sun	0	—	unknown	—	72.6° 10:35	4.52	52%	132.1°
2047-07-01 Mon	0	—	unknown	—	72.6° 10:30	4.54	64%	146.3°
2047-07-02 Tue	0	—	unknown	—	72.6° 10:25	4.56	74%	160.7°
2047-07-03 Wed	0	—	unknown	—	72.6° 10:20	4.58	84%	175.2°
2047-07-04 Thu	0	—	unknown	—	72.6° 10:15	4.61	92%	170.3°
2047-07-05 Fri	0	—	unknown	—	72.6° 10:15	4.64	97%	155.8°
2047-07-06 Sat	0	—	unknown	—	72.6° 10:10	4.67	100%	141.5°
2047-07-07 Sun	0	—	unknown	—	72.6° 10:05	4.7	100%	127.4°
2047-07-08 Mon	0	—	unknown	—	72.6° 10:00	4.73	97%	113.6°
2047-07-09 Tue	1	—	unknown	—	72.6° 10:00	4.76	92%	100.2°
2047-07-10 Wed	1	—	unknown	—	72.6° 09:55	4.8	86%	87.1°
2047-07-11 Thu	1	—	unknown	—	72.6° 09:50	4.83	78%	74.5°
2047-07-12 Fri	1	—	unknown	—	72.6° 09:45	4.87	70%	62.1°
2047-07-13 Sat	1	—	unknown	—	72.6° 09:40	4.91	60%	50.0°
2047-07-14 Sun	1	—	unknown	—	72.6° 09:40	4.95	51%	38.0°
2047-07-15 Mon	2	—	unknown	—	72.6° 09:35	5.0	41%	26.2°
2047-07-16 Tue	2	—	unknown	03:55–04:00 (marginal, 0.08 h)	72.6° 09:30	5.04	32%	14.3°
2047-07-17 Wed	3	—	unknown	04:35–04:50 (marginal, 0.25 h)	72.6° 09:25	5.08	24%	2.4°
2047-07-18 Thu	5	—	unknown	04:25–04:50 (marginal, 0.42 h)	72.6° 09:20	5.13	16%	9.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-06-19&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.