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: 03-11 (29), 03-12 (29), 03-08 (28), 03-09 (28), 03-10 (28) — by astronomy; check the weather when the night is within four days.

2041-02-13astronomy score per night — click a bar for that night2041-03-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-02-13 Wed	7	—	unknown	05:15–05:45 (marginal, 0.5 h)	71.1° 10:45	10.31	96%	132.7°
2041-02-14 Thu	7	—	unknown	05:10–05:45 (marginal, 0.58 h)	71.1° 10:40	10.27	99%	132.6°
2041-02-15 Fri	8	—	unknown	05:10–06:15 (marginal, 1.08 h)	71.1° 10:35	10.23	100%	130.3°
2041-02-16 Sat	9	—	unknown	05:40–05:45 (good, 0.08 h)	71.1° 10:35	10.19	99%	126.2°
2041-02-17 Sun	9	—	unknown	05:00–06:15 (marginal, 1.25 h)	71.1° 10:30	10.15	97%	120.5°
2041-02-18 Mon	9	—	unknown	04:55–06:10 (marginal, 1.25 h)	71.1° 10:25	10.11	93%	113.7°
2041-02-19 Tue	9	—	unknown	05:35–05:40 (good, 0.08 h)	71.1° 10:20	10.07	87%	106.0°
2041-02-20 Wed	9	—	unknown	05:35–05:40 (good, 0.08 h)	71.1° 10:15	10.03	80%	97.9°
2041-02-21 Thu	9	—	unknown	04:45–06:10 (marginal, 1.42 h)	71.1° 10:15	9.98	71%	89.4°
2041-02-22 Fri	10	—	unknown	05:30–05:35 (good, 0.08 h)	71.1° 10:10	9.94	61%	80.7°
2041-02-23 Sat	12	—	unknown	05:20–05:35 (good, 0.25 h)	71.1° 10:05	9.9	51%	72.1°
2041-02-24 Sun	13	—	unknown	05:15–05:30 (good, 0.25 h)	71.1° 10:00	9.85	40%	63.9°
2041-02-25 Mon	15	—	unknown	05:05–05:30 (good, 0.42 h)	71.1° 09:55	9.81	29%	56.5°
2041-02-26 Tue	18	—	unknown	04:50–05:30 (good, 0.67 h)	71.1° 09:55	9.77	20%	50.7°
2041-02-27 Wed	20	—	unknown	04:50–05:25 (good, 0.58 h)	71.1° 09:50	9.72	11%	47.5°
2041-02-28 Thu	21	—	unknown	04:45–05:25 (good, 0.67 h)	71.1° 09:45	9.68	5%	47.7°
2041-03-01 Fri	22	—	unknown	04:40–05:25 (good, 0.75 h)	71.1° 09:40	9.63	1%	51.4°
2041-03-02 Sat	23	—	unknown	04:35–05:25 (good, 0.83 h)	71.1° 09:40	9.58	0%	58.0°
2041-03-03 Sun	23	—	unknown	04:30–05:20 (good, 0.83 h)	71.1° 09:35	9.54	3%	66.3°
2041-03-04 Mon	24	—	unknown	04:30–05:20 (good, 0.83 h)	71.1° 09:30	9.49	8%	75.5°
2041-03-05 Tue	25	—	unknown	04:25–05:20 (good, 0.92 h)	71.1° 09:25	9.45	15%	85.0°
2041-03-06 Wed	25	—	unknown	04:20–05:15 (good, 0.92 h)	71.1° 09:20	9.4	23%	94.3°
2041-03-07 Thu	26	—	unknown	04:15–05:15 (good, 1.0 h)	71.1° 09:20	9.35	33%	103.2°
2041-03-08 Fri	28	—	unknown	04:15–05:15 (good, 1.0 h)	71.1° 09:15	9.3	43%	111.4°
2041-03-09 Sat	28	—	unknown	04:10–05:10 (good, 1.0 h)	71.1° 09:10	9.25	53%	118.7°
2041-03-10 Sun	28	—	unknown	04:05–05:10 (good, 1.08 h)	71.1° 09:05	9.21	62%	124.8°
2041-03-11 Mon	29	—	unknown	04:05–05:10 (good, 1.08 h)	71.1° 09:00	9.16	71%	129.4°
2041-03-12 Tue	29	—	unknown	04:05–05:05 (good, 1.0 h)	71.1° 09:00	9.11	80%	132.2°
2041-03-13 Wed	27	—	unknown	04:00–05:05 (good, 1.08 h)	71.1° 08:55	9.06	86%	132.7°
2041-03-14 Thu	26	—	unknown	04:00–05:00 (good, 1.0 h)	71.1° 08:50	9.01	92%	131.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-02-13&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.