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: 03-05 (26), 03-06 (26), 03-07 (25), 03-03 (24), 03-04 (24) — by astronomy; check the weather when the night is within four days.

2028-02-15astronomy score per night — click a bar for that night2028-03-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-02-15 Tue	6	—	unknown	05:10–05:45 (marginal, 0.58 h)	71.1° 10:40	10.27	65%	92.9°
2028-02-16 Wed	7	—	unknown	05:05–05:45 (marginal, 0.67 h)	71.1° 10:35	10.23	54%	82.9°
2028-02-17 Thu	8	—	unknown	05:05–06:15 (marginal, 1.17 h)	71.1° 10:30	10.18	44%	73.3°
2028-02-18 Fri	9	—	unknown	05:35–05:40 (good, 0.08 h)	71.1° 10:30	10.14	34%	64.4°
2028-02-19 Sat	10	—	unknown	05:30–05:40 (good, 0.17 h)	71.1° 10:25	10.1	25%	56.4°
2028-02-20 Sun	12	—	unknown	05:25–05:40 (good, 0.25 h)	71.1° 10:20	10.06	17%	49.7°
2028-02-21 Mon	14	—	unknown	05:15–05:35 (good, 0.33 h)	71.1° 10:15	10.02	10%	44.6°
2028-02-22 Tue	15	—	unknown	05:10–05:35 (good, 0.42 h)	71.1° 10:10	9.98	6%	41.8°
2028-02-23 Wed	17	—	unknown	05:05–05:35 (good, 0.5 h)	71.1° 10:10	9.93	2%	41.6°
2028-02-24 Thu	18	—	unknown	05:05–05:35 (good, 0.5 h)	71.1° 10:05	9.89	0%	44.2°
2028-02-25 Fri	18	—	unknown	05:00–05:30 (good, 0.5 h)	71.1° 10:00	9.85	0%	49.0°
2028-02-26 Sat	19	—	unknown	04:55–05:30 (good, 0.58 h)	71.1° 09:55	9.8	2%	55.4°
2028-02-27 Sun	20	—	unknown	04:50–05:30 (good, 0.67 h)	71.1° 09:50	9.76	6%	63.0°
2028-02-28 Mon	20	—	unknown	04:45–05:25 (good, 0.67 h)	71.1° 09:50	9.71	11%	71.4°
2028-02-29 Tue	22	—	unknown	04:45–05:25 (good, 0.67 h)	71.1° 09:45	9.67	18%	80.4°
2028-03-01 Wed	22	—	unknown	04:40–05:25 (good, 0.75 h)	71.1° 09:40	9.62	26%	89.6°
2028-03-02 Thu	23	—	unknown	04:35–05:25 (good, 0.83 h)	71.1° 09:35	9.58	35%	99.1°
2028-03-03 Fri	24	—	unknown	04:30–05:20 (good, 0.83 h)	71.1° 09:35	9.53	45%	108.6°
2028-03-04 Sat	24	—	unknown	04:25–05:20 (good, 0.92 h)	71.1° 09:30	9.48	56%	117.8°
2028-03-05 Sun	26	—	unknown	04:25–05:20 (good, 0.92 h)	71.1° 09:25	9.44	67%	126.4°
2028-03-06 Mon	26	—	unknown	04:20–05:15 (good, 0.92 h)	71.1° 09:20	9.39	77%	133.5°
2028-03-07 Tue	25	—	unknown	04:20–05:15 (good, 0.92 h)	71.1° 09:15	9.34	86%	137.9°
2028-03-08 Wed	24	—	unknown	04:20–05:15 (good, 0.92 h)	71.1° 09:15	9.29	93%	138.4°
2028-03-09 Thu	23	—	unknown	04:15–05:10 (good, 0.92 h)	71.1° 09:10	9.25	98%	134.6°
2028-03-10 Fri	24	—	unknown	04:15–05:10 (good, 0.92 h)	71.1° 09:05	9.2	100%	127.3°
2028-03-11 Sat	23	—	unknown	04:10–05:05 (good, 0.92 h)	71.1° 09:00	9.15	99%	118.0°
2028-03-12 Sun	21	—	unknown	04:15–05:05 (good, 0.83 h)	71.1° 08:55	9.1	95%	107.6°
2028-03-13 Mon	20	—	unknown	04:15–05:05 (good, 0.83 h)	71.1° 08:55	9.05	88%	97.0°
2028-03-14 Tue	19	—	unknown	04:10–05:00 (good, 0.83 h)	71.1° 08:50	9.0	80%	86.4°
2028-03-15 Wed	20	—	unknown	04:10–05:00 (good, 0.83 h)	71.1° 08:45	8.95	70%	76.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-02-15&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.