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: 02-20 (15), 02-21 (15), 02-19 (14), 02-18 (13), 02-16 (11) — by astronomy; check the weather when the night is within four days.

2029-01-23astronomy score per night — click a bar for that night2029-02-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2029-02-09 Fri	5	—	unknown	05:30–05:50 (marginal, 0.33 h)	71.1° 11:00	10.47	12%	49.1°
2029-02-10 Sat	6	—	unknown	05:55–06:25 (marginal, 0.5 h)	71.1° 10:55	10.43	6%	43.4°
2029-02-11 Sun	7	—	unknown	05:25–06:20 (marginal, 0.92 h)	71.1° 10:50	10.39	2%	40.2°
2029-02-12 Mon	8	—	unknown	05:45–05:50 (good, 0.08 h)	71.1° 10:50	10.35	0%	40.2°
2029-02-13 Tue	8	—	unknown	05:15–06:20 (marginal, 1.08 h)	71.1° 10:45	10.31	0%	43.2°
2029-02-14 Wed	9	—	unknown	05:40–05:45 (good, 0.08 h)	71.1° 10:40	10.27	2%	48.6°
2029-02-15 Thu	9	—	unknown	05:35–05:45 (good, 0.17 h)	71.1° 10:35	10.23	6%	55.6°
2029-02-16 Fri	11	—	unknown	05:30–05:45 (good, 0.25 h)	71.1° 10:35	10.19	11%	63.5°
2029-02-17 Sat	11	—	unknown	05:25–05:40 (good, 0.25 h)	71.1° 10:30	10.15	18%	72.0°
2029-02-18 Sun	13	—	unknown	05:25–05:40 (good, 0.25 h)	71.1° 10:25	10.11	25%	80.9°
2029-02-19 Mon	14	—	unknown	05:20–05:40 (good, 0.33 h)	71.1° 10:20	10.07	34%	90.0°
2029-02-20 Tue	15	—	unknown	05:15–05:40 (good, 0.42 h)	71.1° 10:15	10.03	43%	99.2°
2029-02-21 Wed	15	—	unknown	05:10–05:35 (good, 0.42 h)	71.1° 10:15	9.99	53%	108.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-01-23&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.