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: 05-14 (88), 05-12 (87), 05-13 (87), 05-11 (86), 05-15 (86) — by astronomy; check the weather when the night is within four days.

2035-04-24astronomy score per night — click a bar for that night2035-05-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-04-24 Tue	27	—	unknown	04:30–04:45 (good, 0.25 h)	71.1° 07:10	6.78	94%	70.1°
2035-04-25 Wed	26	—	unknown	01:50–04:45 (marginal, 2.92 h)	71.1° 07:05	6.72	90%	61.5°
2035-04-26 Thu	26	—	unknown	01:40–04:40 (marginal, 3.0 h)	71.1° 07:05	6.67	83%	53.7°
2035-04-27 Fri	29	—	unknown	04:30–04:40 (good, 0.17 h)	71.1° 07:00	6.61	75%	47.0°
2035-04-28 Sat	33	—	unknown	03:05–04:35 (good, 1.5 h)	71.1° 06:55	6.55	67%	42.0°
2035-04-29 Sun	42	—	unknown	01:50–04:35 (good, 2.75 h)	71.1° 06:50	6.49	57%	39.4°
2035-04-30 Mon	55	—	unknown	01:45–04:35 (good, 2.83 h)	71.1° 06:50	6.43	48%	39.8°
2035-05-01 Tue	63	—	unknown	01:40–04:30 (good, 2.83 h)	71.1° 06:45	6.37	38%	43.3°
2035-05-02 Wed	70	—	unknown	01:40–04:30 (good, 2.83 h)	71.1° 06:40	6.32	28%	49.4°
2035-05-03 Thu	77	—	unknown	01:35–04:30 (good, 2.92 h)	71.1° 06:35	6.26	19%	57.5°
2035-05-04 Fri	77	—	unknown	01:30–04:25 (good, 2.92 h)	71.1° 06:30	6.2	11%	67.1°
2035-05-05 Sat	79	—	unknown	01:25–04:25 (good, 3.0 h)	71.1° 06:30	6.14	5%	77.7°
2035-05-06 Sun	81	—	unknown	01:25–04:25 (good, 3.0 h)	71.1° 06:25	6.09	1%	88.9°
2035-05-07 Mon	82	—	unknown	01:20–04:20 (good, 3.0 h)	71.1° 06:20	6.03	0%	100.3°
2035-05-08 Tue	82	—	unknown	01:15–04:20 (good, 3.08 h)	71.1° 06:15	5.97	2%	111.6°
2035-05-09 Wed	83	—	unknown	01:10–04:15 (good, 3.08 h)	71.1° 06:10	5.92	7%	122.1°
2035-05-10 Thu	85	—	unknown	01:05–04:15 (good, 3.17 h)	71.1° 06:10	5.86	14%	131.2°
2035-05-11 Fri	86	—	unknown	01:05–04:15 (good, 3.17 h)	71.1° 06:05	5.81	23%	137.8°
2035-05-12 Sat	87	—	unknown	01:00–04:10 (good, 3.17 h)	71.1° 06:00	5.75	33%	140.7°
2035-05-13 Sun	87	—	unknown	01:00–04:10 (good, 3.17 h)	71.1° 05:55	5.7	44%	139.4°
2035-05-14 Mon	88	—	unknown	00:55–04:10 (good, 3.25 h)	71.1° 05:55	5.64	55%	134.6°
2035-05-15 Tue	86	—	unknown	00:55–04:05 (good, 3.17 h)	71.1° 05:50	5.59	66%	127.5°
2035-05-16 Wed	86	—	unknown	00:50–04:05 (good, 3.25 h)	71.1° 05:45	5.53	75%	119.1°
2035-05-17 Thu	75	—	unknown	00:55–04:05 (good, 3.17 h)	71.1° 05:40	5.48	83%	110.0°
2035-05-18 Fri	66	—	unknown	00:55–04:05 (good, 3.17 h)	71.1° 05:35	5.43	90%	100.6°
2035-05-19 Sat	56	—	unknown	01:20–04:00 (good, 2.67 h)	71.1° 05:35	5.38	95%	91.1°
2035-05-20 Sun	48	—	unknown	02:05–04:00 (good, 1.92 h)	71.1° 05:30	5.33	98%	81.7°
2035-05-21 Mon	41	—	unknown	02:50–04:00 (good, 1.17 h)	71.1° 05:25	5.28	100%	72.6°
2035-05-22 Tue	35	—	unknown	03:40–03:55 (good, 0.25 h)	71.1° 05:20	5.23	99%	63.9°
2035-05-23 Wed	32	—	unknown	00:00–03:55 (marginal, 3.92 h)	71.1° 05:15	5.18	97%	55.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-04-24&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.