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: 08-17 (100), 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100) — by astronomy; check the weather when the night is within four days.

2036-08-17astronomy score per night — click a bar for that night2036-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-08-17 Sun	100	—	unknown	22:05–04:40 (good, 6.58 h)	71.1° 23:35	6.79	20%	129.8°
2036-08-18 Mon	100	—	unknown	22:00–04:40 (good, 6.67 h)	71.1° 23:30	6.85	11%	136.0°
2036-08-19 Tue	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.91	5%	138.8°
2036-08-20 Wed	100	—	unknown	22:00–04:30 (good, 6.5 h)	71.1° 23:25	6.96	1%	137.2°
2036-08-21 Thu	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:20	7.02	0%	131.6°
2036-08-22 Fri	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:15	7.08	2%	123.2°
2036-08-23 Sat	100	—	unknown	21:50–04:20 (good, 6.5 h)	71.1° 23:15	7.13	7%	113.4°
2036-08-24 Sun	100	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.19	14%	103.1°
2036-08-25 Mon	100	—	unknown	21:50–04:10 (good, 6.33 h)	71.1° 23:05	7.25	23%	92.6°
2036-08-26 Tue	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:00	7.31	33%	82.5°
2036-08-27 Wed	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 22:55	7.36	43%	72.9°
2036-08-28 Thu	100	—	unknown	21:40–04:00 (good, 6.33 h)	71.1° 22:55	7.42	53%	64.0°
2036-08-29 Fri	98	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.48	63%	56.0°
2036-08-30 Sat	92	—	unknown	21:40–03:50 (good, 6.17 h)	71.1° 22:45	7.53	72%	49.3°
2036-08-31 Sun	86	—	unknown	23:00–03:45 (good, 4.75 h)	71.1° 22:40	7.59	80%	44.3°
2036-09-01 Mon	69	—	unknown	03:25–03:45 (good, 0.33 h)	71.1° 22:35	7.64	87%	41.6°
2036-09-02 Tue	44	—	unknown	21:30–04:00 (marginal, 6.5 h)	71.1° 22:35	7.7	93%	41.5°
2036-09-03 Wed	42	—	unknown	21:30–03:45 (marginal, 6.25 h)	71.1° 22:30	7.75	97%	44.2°
2036-09-04 Thu	44	—	unknown	21:30–03:35 (marginal, 6.08 h)	71.1° 22:25	7.81	99%	49.1°
2036-09-05 Fri	51	—	unknown	21:25–21:40 (good, 0.25 h)	71.1° 22:20	7.86	100%	55.7°
2036-09-06 Sat	60	—	unknown	21:25–23:00 (good, 1.58 h)	71.1° 22:20	7.92	99%	63.5°
2036-09-07 Sun	74	—	unknown	21:20–00:35 (good, 3.25 h)	71.1° 22:15	7.97	96%	72.1°
2036-09-08 Mon	100	—	unknown	21:20–01:30 (good, 4.17 h)	71.1° 22:10	8.03	91%	81.2°
2036-09-09 Tue	100	—	unknown	21:20–02:30 (good, 5.17 h)	71.1° 22:05	8.08	84%	90.6°
2036-09-10 Wed	100	—	unknown	21:15–02:50 (good, 5.58 h)	71.1° 22:00	8.14	76%	100.2°
2036-09-11 Thu	100	—	unknown	21:15–02:50 (good, 5.58 h)	71.1° 22:00	8.19	66%	109.7°
2036-09-12 Fri	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:55	8.24	56%	118.9°
2036-09-13 Sat	100	—	unknown	21:10–02:50 (good, 5.67 h)	71.1° 21:50	8.3	44%	127.3°
2036-09-14 Sun	100	—	unknown	21:10–02:50 (good, 5.67 h)	71.1° 21:45	8.35	34%	134.1°
2036-09-15 Mon	100	—	unknown	21:05–02:45 (good, 5.67 h)	71.1° 21:40	8.4	23%	138.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-08-17&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.