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 HD 189733: 02-08 (4), 02-06 (3), 02-07 (3), 02-03 (2), 02-04 (2) — by astronomy; check the weather when the night is within four days.

2029-01-10astronomy score per night — click a bar for that night2029-02-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-01-10 Wed	1	—	unknown	—	71.1° 13:00	11.32	16%	73.6°
2029-01-11 Thu	1	—	unknown	—	71.1° 13:00	11.3	8%	63.7°
2029-01-12 Fri	0	—	unknown	—	71.1° 12:55	11.28	4%	54.8°
2029-01-13 Sat	0	—	unknown	—	71.1° 12:50	11.26	1%	47.4°
2029-01-14 Sun	0	—	unknown	—	71.1° 12:45	11.24	0%	42.2°
2029-01-15 Mon	0	—	unknown	—	71.1° 12:40	11.22	2%	39.9°
2029-01-16 Tue	0	—	unknown	—	71.1° 12:40	11.2	5%	40.8°
2029-01-17 Wed	0	—	unknown	—	71.1° 12:35	11.17	10%	44.7°
2029-01-18 Thu	0	—	unknown	—	71.1° 12:30	11.15	17%	50.6°
2029-01-19 Fri	0	—	unknown	—	71.1° 12:25	11.13	24%	57.9°
2029-01-20 Sat	0	—	unknown	—	71.1° 12:25	11.1	33%	66.0°
2029-01-21 Sun	0	—	unknown	—	71.1° 12:20	11.08	42%	74.6°
2029-01-22 Mon	0	—	unknown	—	71.1° 12:15	11.05	51%	83.7°
2029-01-23 Tue	0	—	unknown	—	71.1° 12:10	11.02	61%	92.9°
2029-01-24 Wed	0	—	unknown	—	71.1° 12:05	10.99	70%	102.3°
2029-01-25 Thu	0	—	unknown	—	71.1° 12:00	10.96	79%	111.7°
2029-01-26 Fri	0	—	unknown	—	71.1° 11:55	10.94	87%	120.8°
2029-01-27 Sat	1	—	unknown	—	71.1° 11:50	10.91	93%	129.2°
2029-01-28 Sun	1	—	unknown	—	71.1° 11:45	10.88	98%	135.9°
2029-01-29 Mon	1	—	unknown	—	71.1° 11:45	10.84	100%	139.7°
2029-01-30 Tue	1	—	unknown	—	71.1° 11:40	10.81	99%	139.5°
2029-01-31 Wed	1	—	unknown	—	71.1° 11:35	10.78	96%	135.1°
2029-02-01 Thu	1	—	unknown	—	71.1° 11:30	10.75	90%	127.6°
2029-02-02 Fri	1	—	unknown	—	71.1° 11:30	10.71	82%	118.2°
2029-02-03 Sat	2	—	unknown	05:55–06:00 (marginal, 0.08 h)	71.1° 11:25	10.68	72%	107.8°
2029-02-04 Sun	2	—	unknown	05:50–05:55 (marginal, 0.08 h)	71.1° 11:20	10.65	61%	97.0°
2029-02-05 Mon	2	—	unknown	05:45–05:55 (marginal, 0.17 h)	71.1° 11:15	10.61	50%	86.2°
2029-02-06 Tue	3	—	unknown	05:45–05:55 (marginal, 0.17 h)	71.1° 11:10	10.58	39%	75.8°
2029-02-07 Wed	3	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:10	10.54	28%	65.9°
2029-02-08 Thu	4	—	unknown	05:35–05:55 (marginal, 0.33 h)	71.1° 11:05	10.5	19%	56.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-01-10&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.