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: 10-07 (100), 10-08 (100), 10-09 (100), 10-10 (100), 10-11 (100) — by astronomy; check the weather when the night is within four days.

2028-09-27astronomy score per night — click a bar for that night2028-10-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-09-27 Wed	57	—	unknown	20:45–00:20 (good, 3.58 h)	71.1° 20:55	9.01	73%	41.5°
2028-09-28 Thu	44	—	unknown	20:40–02:20 (marginal, 5.67 h)	71.1° 20:50	9.06	81%	40.4°
2028-09-29 Fri	37	—	unknown	20:40–02:05 (marginal, 5.42 h)	71.1° 20:45	9.11	88%	42.2°
2028-09-30 Sat	34	—	unknown	20:40–01:50 (marginal, 5.17 h)	71.1° 20:45	9.16	93%	46.5°
2028-10-01 Sun	35	—	unknown	20:35–01:45 (marginal, 5.17 h)	71.1° 20:40	9.2	97%	52.7°
2028-10-02 Mon	39	—	unknown	20:35–01:40 (marginal, 5.08 h)	71.1° 20:35	9.25	99%	60.1°
2028-10-03 Tue	47	—	unknown	20:35–21:30 (good, 0.92 h)	71.1° 20:30	9.3	100%	68.3°
2028-10-04 Wed	58	—	unknown	20:30–22:50 (good, 2.33 h)	71.1° 20:25	9.35	98%	77.1°
2028-10-05 Thu	70	—	unknown	20:30–23:50 (good, 3.33 h)	71.1° 20:25	9.39	95%	86.3°
2028-10-06 Fri	84	—	unknown	20:30–00:45 (good, 4.25 h)	71.1° 20:20	9.44	90%	95.6°
2028-10-07 Sat	100	—	unknown	20:25–01:00 (good, 4.58 h)	71.1° 20:15	9.49	84%	104.9°
2028-10-08 Sun	100	—	unknown	20:25–01:05 (good, 4.67 h)	71.1° 20:10	9.53	76%	114.0°
2028-10-09 Mon	100	—	unknown	20:25–01:05 (good, 4.67 h)	71.1° 20:10	9.58	66%	122.7°
2028-10-10 Tue	100	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:05	9.62	56%	130.4°
2028-10-11 Wed	100	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:00	9.67	45%	136.4°
2028-10-12 Thu	100	—	unknown	20:20–01:00 (good, 4.67 h)	71.1° 19:55	9.71	34%	139.5°
2028-10-13 Fri	100	—	unknown	20:15–01:00 (good, 4.75 h)	71.1° 19:50	9.76	24%	138.8°
2028-10-14 Sat	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:50	9.8	15%	134.1°
2028-10-15 Sun	100	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:45	9.84	7%	126.3°
2028-10-16 Mon	100	—	unknown	20:15–00:45 (good, 4.5 h)	71.1° 19:40	9.89	2%	116.5°
2028-10-17 Tue	100	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:35	9.93	0%	105.6°
2028-10-18 Wed	100	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:30	9.97	1%	94.3°
2028-10-19 Thu	100	—	unknown	20:10–00:35 (good, 4.42 h)	71.1° 19:30	10.01	5%	83.1°
2028-10-20 Fri	100	—	unknown	20:05–00:30 (good, 4.42 h)	71.1° 19:25	10.06	11%	72.4°
2028-10-21 Sat	100	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:20	10.1	19%	62.5°
2028-10-22 Sun	96	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:15	10.14	28%	53.8°
2028-10-23 Mon	87	—	unknown	20:05–00:20 (good, 4.25 h)	71.1° 19:15	10.18	37%	46.8°
2028-10-24 Tue	68	—	unknown	20:00–00:15 (good, 4.25 h)	71.1° 19:10	10.22	47%	42.1°
2028-10-25 Wed	54	—	unknown	20:00–23:45 (good, 3.75 h)	71.1° 19:05	10.26	57%	40.2°
2028-10-26 Thu	43	—	unknown	20:00–21:35 (good, 1.58 h)	71.1° 19:00	10.3	66%	41.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-09-27&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.