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: 04-18 (61), 04-17 (59), 04-16 (52), 04-02 (47), 04-01 (46) — by astronomy; check the weather when the night is within four days.

2039-03-20astronomy score per night — click a bar for that night2039-04-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-03-20 Sun	37	—	unknown	03:30–04:55 (good, 1.42 h)	71.1° 08:30	8.73	15%	46.2°
2039-03-21 Mon	37	—	unknown	03:25–04:50 (good, 1.42 h)	71.1° 08:25	8.68	8%	49.7°
2039-03-22 Tue	38	—	unknown	03:20–04:50 (good, 1.5 h)	71.1° 08:20	8.63	4%	55.3°
2039-03-23 Wed	38	—	unknown	03:15–04:45 (good, 1.5 h)	71.1° 08:15	8.57	1%	62.3°
2039-03-24 Thu	40	—	unknown	03:10–04:45 (good, 1.58 h)	71.1° 08:15	8.52	0%	70.2°
2039-03-25 Fri	41	—	unknown	03:10–04:45 (good, 1.58 h)	71.1° 08:10	8.47	2%	78.5°
2039-03-26 Sat	41	—	unknown	04:05–05:40 (good, 1.58 h)	71.1° 09:05	8.42	5%	87.0°
2039-03-27 Sun	42	—	unknown	04:00–05:40 (good, 1.67 h)	71.1° 09:00	8.36	10%	95.4°
2039-03-28 Mon	42	—	unknown	03:55–05:35 (good, 1.67 h)	71.1° 08:55	8.31	16%	103.6°
2039-03-29 Tue	44	—	unknown	03:50–05:35 (good, 1.75 h)	71.1° 08:55	8.25	23%	111.4°
2039-03-30 Wed	45	—	unknown	03:50–05:35 (good, 1.75 h)	71.1° 08:50	8.2	32%	118.7°
2039-03-31 Thu	45	—	unknown	03:45–05:30 (good, 1.75 h)	71.1° 08:45	8.15	41%	125.1°
2039-04-01 Fri	46	—	unknown	03:40–05:30 (good, 1.83 h)	71.1° 08:40	8.09	50%	130.2°
2039-04-02 Sat	47	—	unknown	03:40–05:30 (good, 1.83 h)	71.1° 08:40	8.04	60%	133.5°
2039-04-03 Sun	46	—	unknown	03:40–05:25 (good, 1.75 h)	71.1° 08:35	7.98	70%	134.4°
2039-04-04 Mon	46	—	unknown	03:35–05:25 (good, 1.83 h)	71.1° 08:30	7.93	79%	132.5°
2039-04-05 Tue	42	—	unknown	03:35–05:20 (good, 1.75 h)	71.1° 08:25	7.87	87%	128.0°
2039-04-06 Wed	41	—	unknown	03:30–05:20 (good, 1.83 h)	71.1° 08:20	7.81	93%	121.2°
2039-04-07 Thu	38	—	unknown	03:30–05:20 (good, 1.83 h)	71.1° 08:20	7.76	98%	112.7°
2039-04-08 Fri	33	—	unknown	03:35–05:15 (good, 1.67 h)	71.1° 08:15	7.7	100%	103.1°
2039-04-09 Sat	30	—	unknown	03:55–05:15 (good, 1.33 h)	71.1° 08:10	7.64	99%	92.8°
2039-04-10 Sun	26	—	unknown	04:25–05:10 (good, 0.75 h)	71.1° 08:05	7.59	95%	82.4°
2039-04-11 Mon	25	—	unknown	04:40–05:10 (good, 0.5 h)	71.1° 08:00	7.53	89%	72.3°
2039-04-12 Tue	26	—	unknown	04:30–05:10 (good, 0.67 h)	71.1° 08:00	7.47	80%	63.0°
2039-04-13 Wed	28	—	unknown	03:45–05:05 (good, 1.33 h)	71.1° 07:55	7.42	70%	55.1°
2039-04-14 Thu	34	—	unknown	03:10–05:05 (good, 1.92 h)	71.1° 07:50	7.36	59%	49.2°
2039-04-15 Fri	44	—	unknown	02:45–05:00 (good, 2.25 h)	71.1° 07:45	7.3	48%	46.1°
2039-04-16 Sat	52	—	unknown	02:40–05:00 (good, 2.33 h)	71.1° 07:45	7.24	37%	46.0°
2039-04-17 Sun	59	—	unknown	02:35–05:00 (good, 2.42 h)	71.1° 07:40	7.19	27%	48.8°
2039-04-18 Mon	61	—	unknown	02:35–04:55 (good, 2.33 h)	71.1° 07:35	7.13	19%	53.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-03-20&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.