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: 05-27 (100), 05-28 (100), 05-29 (100), 05-30 (100), 05-31 (100) — by astronomy; check the weather when the night is within four days.

2038-05-15astronomy score per night — click a bar for that night2038-06-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-05-15 Sat	65	—	unknown	01:05–04:05 (good, 3.0 h)	71.1° 05:50	5.57	88%	103.6°
2038-05-16 Sun	56	—	unknown	01:20–04:05 (good, 2.75 h)	71.1° 05:45	5.52	95%	93.0°
2038-05-17 Mon	47	—	unknown	02:10–04:05 (good, 1.92 h)	71.1° 05:40	5.47	99%	82.3°
2038-05-18 Tue	39	—	unknown	03:00–04:00 (good, 1.0 h)	71.1° 05:35	5.42	100%	71.8°
2038-05-19 Wed	35	—	unknown	03:40–04:00 (good, 0.33 h)	71.1° 05:30	5.37	98%	62.2°
2038-05-20 Thu	34	—	unknown	00:10–04:00 (marginal, 3.83 h)	71.1° 05:30	5.32	94%	54.1°
2038-05-21 Fri	36	—	unknown	00:00–04:00 (marginal, 4.0 h)	71.1° 05:25	5.27	87%	48.1°
2038-05-22 Sat	56	—	unknown	01:40–03:55 (good, 2.25 h)	71.1° 05:20	5.22	78%	44.9°
2038-05-23 Sun	69	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:15	5.17	69%	44.8°
2038-05-24 Mon	80	—	unknown	00:10–03:55 (good, 3.75 h)	71.1° 05:10	5.12	59%	47.5°
2038-05-25 Tue	90	—	unknown	00:05–03:55 (good, 3.83 h)	71.1° 05:10	5.08	49%	52.4°
2038-05-26 Wed	98	—	unknown	00:05–03:50 (good, 3.75 h)	71.1° 05:05	5.03	40%	58.8°
2038-05-27 Thu	100	—	unknown	00:00–03:50 (good, 3.83 h)	71.1° 05:00	4.99	31%	66.1°
2038-05-28 Fri	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 04:55	4.95	22%	74.0°
2038-05-29 Sat	100	—	unknown	23:50–03:50 (good, 4.0 h)	71.1° 04:55	4.91	15%	82.2°
2038-05-30 Sun	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:50	4.87	9%	90.6°
2038-05-31 Mon	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:45	4.83	4%	99.1°
2038-06-01 Tue	100	—	unknown	23:40–03:45 (good, 4.08 h)	71.1° 04:40	4.79	1%	107.5°
2038-06-02 Wed	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:35	4.76	0%	115.5°
2038-06-03 Thu	100	—	unknown	23:30–03:45 (good, 4.25 h)	71.1° 04:35	4.72	1%	122.8°
2038-06-04 Fri	100	—	unknown	23:30–03:45 (good, 4.25 h)	71.1° 04:30	4.69	4%	129.0°
2038-06-05 Sat	100	—	unknown	23:25–03:40 (good, 4.25 h)	71.1° 04:25	4.66	8%	133.5°
2038-06-06 Sun	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 04:20	4.63	15%	135.5°
2038-06-07 Mon	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 04:15	4.6	23%	134.5°
2038-06-08 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:15	4.58	33%	130.5°
2038-06-09 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:10	4.55	44%	124.2°
2038-06-10 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:05	4.53	55%	116.0°
2038-06-11 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:00	4.51	66%	106.7°
2038-06-12 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:00	4.49	77%	96.7°
2038-06-13 Sun	80	—	unknown	23:40–03:40 (good, 4.0 h)	71.1° 03:55	4.48	86%	86.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-05-15&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.