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: 05-23 (99), 05-24 (99), 05-25 (99), 05-21 (98), 05-22 (98) — by astronomy; check the weather when the night is within four days.

2034-05-09astronomy score per night — click a bar for that night2034-06-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-05-09 Tue	42	—	unknown	01:40–04:15 (good, 2.58 h)	71.1° 06:10	5.9	66%	38.3°
2034-05-10 Wed	59	—	unknown	01:05–04:15 (good, 3.17 h)	71.1° 06:05	5.85	56%	38.6°
2034-05-11 Thu	69	—	unknown	01:00–04:15 (good, 3.25 h)	71.1° 06:05	5.79	45%	42.5°
2034-05-12 Fri	78	—	unknown	01:00–04:10 (good, 3.17 h)	71.1° 06:00	5.74	34%	49.4°
2034-05-13 Sat	86	—	unknown	00:55–04:10 (good, 3.25 h)	71.1° 05:55	5.68	24%	58.5°
2034-05-14 Sun	90	—	unknown	00:50–04:10 (good, 3.33 h)	71.1° 05:50	5.63	15%	69.0°
2034-05-15 Mon	90	—	unknown	00:45–04:05 (good, 3.33 h)	71.1° 05:50	5.57	7%	80.4°
2034-05-16 Tue	92	—	unknown	00:40–04:05 (good, 3.42 h)	71.1° 05:45	5.52	2%	92.2°
2034-05-17 Wed	94	—	unknown	00:40–04:05 (good, 3.42 h)	71.1° 05:40	5.47	0%	104.1°
2034-05-18 Thu	94	—	unknown	00:35–04:00 (good, 3.42 h)	71.1° 05:35	5.42	1%	115.6°
2034-05-19 Fri	94	—	unknown	00:30–04:00 (good, 3.5 h)	71.1° 05:30	5.37	5%	125.9°
2034-05-20 Sat	96	—	unknown	00:25–04:00 (good, 3.58 h)	71.1° 05:30	5.32	11%	134.4°
2034-05-21 Sun	98	—	unknown	00:25–04:00 (good, 3.58 h)	71.1° 05:25	5.27	20%	140.1°
2034-05-22 Mon	98	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:20	5.22	29%	141.9°
2034-05-23 Tue	99	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:15	5.17	39%	139.8°
2034-05-24 Wed	99	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:10	5.13	49%	134.7°
2034-05-25 Thu	99	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:10	5.08	59%	127.6°
2034-05-26 Fri	98	—	unknown	00:10–03:50 (good, 3.67 h)	71.1° 05:05	5.04	69%	119.4°
2034-05-27 Sat	96	—	unknown	00:10–03:50 (good, 3.67 h)	71.1° 05:00	4.99	77%	110.6°
2034-05-28 Sun	79	—	unknown	00:15–03:50 (good, 3.58 h)	71.1° 04:55	4.95	85%	101.5°
2034-05-29 Mon	69	—	unknown	00:20–03:50 (good, 3.5 h)	71.1° 04:55	4.91	91%	92.2°
2034-05-30 Tue	59	—	unknown	01:05–03:45 (good, 2.67 h)	71.1° 04:50	4.87	95%	82.9°
2034-05-31 Wed	50	—	unknown	01:55–03:45 (good, 1.83 h)	71.1° 04:45	4.83	98%	73.7°
2034-06-01 Thu	42	—	unknown	02:50–03:45 (good, 0.92 h)	71.1° 04:40	4.79	100%	64.8°
2034-06-02 Fri	36	—	unknown	23:25–03:45 (marginal, 4.33 h)	71.1° 04:35	4.76	99%	56.3°
2034-06-03 Sat	32	—	unknown	23:15–03:45 (marginal, 4.5 h)	71.1° 04:35	4.72	97%	48.8°
2034-06-04 Sun	33	—	unknown	23:10–03:45 (marginal, 4.58 h)	71.1° 04:30	4.69	93%	42.7°
2034-06-05 Mon	41	—	unknown	23:00–03:40 (marginal, 4.67 h)	71.1° 04:25	4.66	87%	38.9°
2034-06-06 Tue	64	—	unknown	23:20–00:05 (good, 0.75 h)	71.1° 04:20	4.63	79%	38.4°
2034-06-07 Wed	78	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:15	4.61	70%	41.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-05-09&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.