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: 07-26 (100), 07-27 (100), 07-28 (100), 08-05 (100), 08-06 (100) — by astronomy; check the weather when the night is within four days.

2042-07-26astronomy score per night — click a bar for that night2042-08-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-07-26 Sat	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.53	66%	81.2°
2042-07-27 Sun	100	—	unknown	22:45–04:20 (good, 5.58 h)	71.1° 01:00	5.58	75%	73.1°
2042-07-28 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.64	84%	65.2°
2042-07-29 Tue	98	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.69	90%	58.0°
2042-07-30 Wed	90	—	unknown	01:15–04:25 (good, 3.17 h)	71.1° 00:50	5.74	96%	52.0°
2042-07-31 Thu	53	—	unknown	22:35–04:25 (marginal, 5.83 h)	71.1° 00:45	5.8	99%	48.1°
2042-08-01 Fri	51	—	unknown	22:35–04:25 (marginal, 5.83 h)	71.1° 00:40	5.85	100%	47.0°
2042-08-02 Sat	55	—	unknown	22:35–23:05 (good, 0.5 h)	71.1° 00:35	5.91	98%	49.1°
2042-08-03 Sun	66	—	unknown	22:30–00:20 (good, 1.83 h)	71.1° 00:35	5.97	93%	54.1°
2042-08-04 Mon	74	—	unknown	22:30–02:25 (good, 3.92 h)	71.1° 00:30	6.02	86%	61.4°
2042-08-05 Tue	100	—	unknown	22:25–03:35 (good, 5.17 h)	71.1° 00:25	6.08	77%	70.0°
2042-08-06 Wed	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.13	67%	79.4°
2042-08-07 Thu	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:15	6.19	56%	89.0°
2042-08-08 Fri	100	—	unknown	22:20–04:35 (good, 6.25 h)	71.1° 00:15	6.25	44%	98.6°
2042-08-09 Sat	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:10	6.3	34%	107.7°
2042-08-10 Sun	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:05	6.36	24%	116.0°
2042-08-11 Mon	100	—	unknown	22:15–04:40 (good, 6.42 h)	71.1° 00:00	6.42	15%	123.2°
2042-08-12 Tue	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 00:00	6.48	8%	128.8°
2042-08-13 Wed	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 23:55	6.53	4%	132.2°
2042-08-14 Thu	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:50	6.59	1%	133.0°
2042-08-15 Fri	100	—	unknown	22:10–04:50 (good, 6.67 h)	71.1° 23:45	6.65	0%	131.3°
2042-08-16 Sat	100	—	unknown	22:05–04:50 (good, 6.75 h)	71.1° 23:40	6.71	2%	127.4°
2042-08-17 Sun	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.1° 23:40	6.76	5%	121.9°
2042-08-18 Mon	100	—	unknown	22:05–04:40 (good, 6.58 h)	71.1° 23:35	6.82	9%	115.3°
2042-08-19 Tue	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.88	16%	108.0°
2042-08-20 Wed	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:25	6.94	23%	100.2°
2042-08-21 Thu	100	—	unknown	21:55–04:30 (good, 6.58 h)	71.1° 23:20	6.99	32%	92.2°
2042-08-22 Fri	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:20	7.05	41%	84.1°
2042-08-23 Sat	100	—	unknown	21:55–04:20 (good, 6.42 h)	71.1° 23:15	7.11	50%	76.0°
2042-08-24 Sun	100	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.17	60%	68.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-07-26&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.