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: 10-30 (100), 10-31 (100), 11-01 (100), 11-02 (100), 10-15 (99) — by astronomy; check the weather when the night is within four days.

2045-10-15astronomy score per night — click a bar for that night2045-11-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-10-15 Sun	99	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:45	9.84	32%	56.8°
2045-10-16 Mon	91	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:40	9.88	42%	50.3°
2045-10-17 Tue	79	—	unknown	20:10–00:45 (good, 4.58 h)	71.1° 19:35	9.92	51%	45.6°
2045-10-18 Wed	58	—	unknown	20:10–00:15 (good, 4.08 h)	71.1° 19:35	9.97	61%	43.2°
2045-10-19 Thu	47	—	unknown	20:10–22:10 (good, 2.0 h)	71.1° 19:30	10.01	70%	43.4°
2045-10-20 Fri	40	—	unknown	20:05–00:50 (marginal, 4.75 h)	71.1° 19:25	10.05	78%	46.1°
2045-10-21 Sat	35	—	unknown	20:05–00:40 (marginal, 4.58 h)	71.1° 19:20	10.09	85%	50.9°
2045-10-22 Sun	34	—	unknown	20:05–00:30 (marginal, 4.42 h)	71.1° 19:20	10.13	91%	57.4°
2045-10-23 Mon	36	—	unknown	20:05–00:25 (marginal, 4.33 h)	71.1° 19:15	10.17	96%	65.1°
2045-10-24 Tue	42	—	unknown	20:00–21:10 (good, 1.17 h)	71.1° 19:10	10.21	99%	73.6°
2045-10-25 Wed	50	—	unknown	20:00–21:55 (good, 1.92 h)	71.1° 19:05	10.25	100%	82.6°
2045-10-26 Thu	60	—	unknown	20:00–22:50 (good, 2.83 h)	71.1° 19:00	10.29	99%	92.1°
2045-10-27 Fri	71	—	unknown	20:00–23:40 (good, 3.67 h)	71.1° 19:00	10.33	95%	101.6°
2045-10-28 Sat	83	—	unknown	19:55–23:45 (good, 3.83 h)	71.1° 18:55	10.37	90%	111.0°
2045-10-29 Sun	98	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:50	10.41	82%	119.9°
2045-10-30 Mon	100	—	unknown	18:55–22:45 (good, 3.83 h)	71.1° 17:45	10.44	73%	127.7°
2045-10-31 Tue	100	—	unknown	18:55–22:45 (good, 3.83 h)	71.1° 17:40	10.48	63%	133.6°
2045-11-01 Wed	100	—	unknown	18:50–22:45 (good, 3.92 h)	71.1° 17:40	10.52	52%	136.8°
2045-11-02 Thu	100	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:35	10.55	41%	136.5°
2045-11-03 Fri	99	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:30	10.59	30%	132.6°
2045-11-04 Sat	98	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:25	10.62	20%	125.8°
2045-11-05 Sun	96	—	unknown	18:50–22:30 (good, 3.67 h)	71.1° 17:25	10.66	11%	117.3°
2045-11-06 Mon	95	—	unknown	18:45–22:25 (good, 3.67 h)	71.1° 17:20	10.69	5%	107.6°
2045-11-07 Tue	94	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:15	10.72	1%	97.5°
2045-11-08 Wed	93	—	unknown	18:45–22:15 (good, 3.5 h)	71.1° 17:10	10.76	0%	87.3°
2045-11-09 Thu	91	—	unknown	18:45–22:15 (good, 3.5 h)	71.1° 17:05	10.79	1%	77.3°
2045-11-10 Fri	90	—	unknown	18:45–22:10 (good, 3.42 h)	71.1° 17:05	10.82	5%	68.0°
2045-11-11 Sat	90	—	unknown	18:40–22:05 (good, 3.42 h)	71.1° 17:00	10.85	10%	59.5°
2045-11-12 Sun	82	—	unknown	18:40–22:00 (good, 3.33 h)	71.1° 16:55	10.88	17%	52.3°
2045-11-13 Mon	72	—	unknown	18:40–22:00 (good, 3.33 h)	71.1° 16:50	10.91	25%	46.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-10-15&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.