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: 05-07 (82), 05-08 (82), 05-06 (81), 05-05 (79), 05-03 (77) — by astronomy; check the weather when the night is within four days.

2035-04-09astronomy score per night — click a bar for that night2035-05-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-04-09 Mon	54	—	unknown	03:10–05:15 (good, 2.08 h)	71.1° 08:10	7.65	3%	93.7°
2035-04-10 Tue	53	—	unknown	03:05–05:10 (good, 2.08 h)	71.1° 08:05	7.59	8%	104.9°
2035-04-11 Wed	55	—	unknown	03:00–05:10 (good, 2.17 h)	71.1° 08:00	7.53	16%	115.7°
2035-04-12 Thu	56	—	unknown	02:55–05:10 (good, 2.25 h)	71.1° 08:00	7.48	26%	125.6°
2035-04-13 Fri	57	—	unknown	02:55–05:05 (good, 2.17 h)	71.1° 07:55	7.42	37%	133.7°
2035-04-14 Sat	58	—	unknown	02:50–05:05 (good, 2.25 h)	71.1° 07:50	7.36	48%	139.2°
2035-04-15 Sun	57	—	unknown	02:50–05:00 (good, 2.17 h)	71.1° 07:45	7.3	59%	140.9°
2035-04-16 Mon	57	—	unknown	02:45–05:00 (good, 2.25 h)	71.1° 07:45	7.25	70%	138.7°
2035-04-17 Tue	58	—	unknown	02:45–05:00 (good, 2.25 h)	71.1° 07:40	7.19	79%	133.3°
2035-04-18 Wed	53	—	unknown	02:45–04:55 (good, 2.17 h)	71.1° 07:35	7.13	87%	125.8°
2035-04-19 Thu	50	—	unknown	02:40–04:55 (good, 2.25 h)	71.1° 07:30	7.07	93%	117.1°
2035-04-20 Fri	45	—	unknown	02:45–04:55 (good, 2.17 h)	71.1° 07:25	7.01	97%	107.8°
2035-04-21 Sat	39	—	unknown	02:50–04:50 (good, 2.0 h)	71.1° 07:25	6.96	100%	98.2°
2035-04-22 Sun	34	—	unknown	03:25–04:50 (good, 1.42 h)	71.1° 07:20	6.9	100%	88.6°
2035-04-23 Mon	30	—	unknown	04:00–04:45 (good, 0.75 h)	71.1° 07:15	6.84	98%	79.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-04-09&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.